Early Reports for September and October, 2000
Testing the Equipment and the Seeing
The Seeing Improves
Testing the Limits of Magnification
Putting on the Cool Shades
Confirmation!
Detailed Filter Checks Deepsky and Jupiter
Will the Real Veil Nebula Please Stand Out?
One for Mulder and Scully
Shining Bow Star Arc Put in its Place
The Quest for the Crescent Begins
Don't Blink You Might Miss It
The Crescent Quest Continues
What a Difference the Seeing Makes
Reports for December, 2000

Testing the Equipment and the Seeing

Managed to setup the 150 MCT around 6:30 this evening, (just after Vega became easily visible high in the Fall meridian). Made a quick check of Epsilon Lyrae. (The famous "Double-Double" consisting of two pairs separated by about 3.5 arc-minutes. Each pair is again double. The wider pair consisting of a 4.6 primary and 6.3 secondary separated by 2.9 arc-seconds. The closer pair of magnitudes 4.9 and 5.2 separated by 2.4 arc-seconds.) Elongated at 70X, wouldn't cleanly split even at 180. -- Not a good sign.

Sighted on Vega -- lots of scintillation - even some transverse chromatic aberration. Quite bad. Re-aligned the finder, made a quick out of focus test. The image "roiled". I assumed this was mostly due to tube currents, but in reviewing my previous notes, its now pretty clear that the atmosphere was just plain unsteady, (Last Sunday I had a clean split of the double-double immediately after setup.)

Next I did an out of focus test. Once again lots of shifting bubbles of light and dark splotches in the defocused image. I noticed in doing this test that the brightest intensity of light kept shifting to the outermost defocus ring. (Need to look into this to see if it's normal.)

NOTE: Found a site on the web which showed graphics of various star images. An animated gif was used to show what good optics would display when seeing is poor. This is what I saw in my scope....

The moon was well above the treetops to the southwest. Decided to take a quick look at 70 & 180X. The moon "boiled" also. I hoped things would improve as the evening progressed -- and the scope stabilized.

As the sky darkened, I decided to estimate limiting visible magnitude based on stars in the Little Dipper. Donning my specs, I could make out the Milky Way through Cygnus, so I figured I could see down to about magnitude 4.5. But I could not quite make out all the stars of the dipper and handle. Thus I could not quite see down to magnitude 5 (at that time).

Time now around 7:15, (should I get a watch?) and I'm still not getting a clean split of the double-double. As usual I keep fiddling with the focuser in hopes of fixing the problem -- another bad sign...

With the moon still above the trees, I decide to look up M13 (M22 is late in season -- but "The Great Cluster of the North" is still well above the horizon.) M13 was easy to locate in the finder. I ran it up at 50X using the 35mm Ultrascopic. At 50X it appears "coarse" with only a suggestion of stars in the outer 15% of the globe. 120x (15mm Ultra) gives a very satisfying view -- but unlike M22, it takes the right kind of "looking" to resolve and get that 3D experience which comes from really "seeing" it. I'm sure that this "special way of looking" at M13 is not necessary in a 10 inch. Bumped the magnification up to 180X (10mm Ultra). M13 just wouldn't take it this evening. The sky is just too unstable...

I made no real effort to add stars to my M13 eyepiece impression, this will have to wait for when I have more patience and conditions are more supportive.

Luna finally dropped below the treeline. This would have little effect on the sky, but it certainly helped my visual adaptation. I could now just make out all the stars in the little dipper. So my visual, unaided limiting magnitude was now 5.0 (based on the photographic magnitude of Eta UMI the dimmest component of the familiar "dipper" shape). Knowing that the 150 typically adds 7.5 magnitude to my eye, this should give me a telescopic limiting magnitude of about 12.5 (while using the 15mm Ultra at 120X).

Decided to go ahead with in and out of focus tests on Vega -- despite the conditions -- if only to get somekind of experience. Vega was still unstable but the chromatic aberration was gone so I assumed that my scope finally stabilized (at least).

NOTE: Based on the examples shown on the website mentioned in an earlier note, the optics in my 150 Mak Cas are good to excellent. (This assumes that a full out-focus test would echo the in-focus results documented above.)

Using the 10mm eyepiece, I viewed the false image of Vega inside focus. Noticed a dimple of light in the middle, surrounded by a dark void (caused by the secondary obstruction) circumscribed by a bright, circular concentric ring of light. As I continued to push inside focus, I saw the annulus of light clone itself up to four times. The annulus of each clone was perfectly concentric to its siblings. The brightest rings continued to be the inner and outermost.

NOTE: Much later I downloaded a piece of software designed to emulate star tests. My brief experience with it suggested that an "unobstructed" scope (a refractor) should dustribute light outward with dominishing intensity. Therefore, an MCT probably takes a hit in contrast based on the size ratio of the secondary obstruction.

Based on the wonderful view of Saturn seen on (or about) October 11th, I have to assume that the above inside focus pattern is healthy for a Mak-Cas with a 34% central obstruction.

I next checked the outside focus effect, and quickly learned that it couldn't be done due to a lack of focuser travel. What I did see (two concentric rings) looked pretty much the same as the inside focus results. This, once again, suggests that the optical system is in pretty good shape. (Certainly much better than my first 150mm OTA which showed pronounced, uncorrectable -- un-collimatable-- coma and had to be replaced by the fine folks at Orion.)

NOTE: In a later observation, I simply slid the eyepiece out manually to extend the focal travel. While carefully observing the de-focus rings, I concluded that outside focus was slightly "mushy" compared to inside focus. I believe that this means that the focal cone of the entire optical path is slightly "under-corrected".

During my Vega tests, I was particularly aware of how much glare was visible in the eyepiece. As suggested above, sky transparency was none too good. I attributed the glare to some kind of reflective media -- thin clouds, ice? in the atmosphere. (In fact, as the evening progressed, I saw a great deal of "ground haze".) I also had to de-mystify the meniscus several times due to dew. The technique of de-mystification in catadioptics -- such as the 150 Argonaut -- is technically called "The Laying on of Hands". Basically the technique involves wrapping your hands around the end of the scope for about 15 minutes while you ponder the night sky. Obviously you don't want to make contact with the meniscus.)

NOTE: During a later observation, I made some comparison tests between my 25mm Plossl and Ultrascopic. The Ultrascopic seemed less susceptible to the kind of glare described above. Basically the Ultras have better immunity to internal reflections. (I also noticed that the Ultras had a slightly larger and flatter field of view.)

Decided to take a look at Albireo. In so doing I noticed that it could just be split in the 7X35mm finderscope. In noting this, I did a test with my 7X35 binoculars -- but as you might suspect -- it couldn't be split for lack of stability in supporting the instrument. Did a color check in the scope. Albireo-A appears rich, golden yellow. Albireo-B, aquamarine tending to blue... I hope this definitive observation resolves the "green/blue" controversy surrounding this most exquisite of double-stars.

While making a sweep along Cygnus' spine, I said hello to M29. Some refer to this little troupe of stars as the "Coathanger Cluster". What I saw was a "throne". As a deep-sky magnitude test, I counted the number of stars strictly within the base square of the throne. I saw one without dispute. A second was visible with averted vision. Perhaps others can also take this simple test and report back how many they see under what instrumentation and conditions. (Again make sure you use 120X or so to ensure that your darken the background sky enough and provide enough "retinal participation".)

Referencing my "Field Guide to the Stars" I located the North American Nebula. It's found in the direction of Deneb from Xi Cygni. It's very clear to me why so many of us have problems seeing it... There is no "it" to see. In a small scope it appears as a large expanse devoid of stars. Perhaps with larger scopes equipped with the right filters some emission radiation is perceptible. Am I wrong here or is this really the kind of thing that shutterbugs can point at and say: "Aha, now you know why I do astro-photography?"

NOTE: I later revisited this region. The real NA Nebiula (NGC7000) is actually "luminous". The region I described above is a rather starless expanse of space neighboring the luminosity. The nebula is so extensive that it can not be taken in all at once in my scope. At best you can scan across it, then note transition regions (such as that between "Mexico" and the "Gulf of Mexico".

In keeping with this spirit of nebulosity, I headed off to the region of 52 Cygni for a look at the various branches of the Veil Nebulae. I've seen the Veil through a 10" Dob at a star party. (Very delicate and filled with exquisite detail.) None of this fine delicacy was seen in my long focus 6". (To be honest the 10" had an OIII filter installed.) I could make out a hint of detail, but only near the brightest, most emissve regions of nebulosity. I need to pick up an OIII filter and determine how much impact this will have on revealing detail...

NOTE: I later found that the star "52" mentioned above was actually "41". There is no nebulosity near 41 but there is a nice crescent of shining stars which looks like a parabolic reflector focusing on a point source receptor.

Finished the evening with a look at Saturn and Jupiter (at 180X). By 10:00 both were well above the horizon. Right off I could tell it was a mess. There was no way to get Saturn in focus. (It and Jupiter looked like they were in a "slow boil in oil".) Only two belts could be seen holding up Jupiters ample waist, Cassini was suggested -- but not definitive. It finally became clear to me why "deep-sky" is so popular. There's probably only a handful of days a year when you get the kind of seeing needed to really "knock your socks off" with the planets.

NOTE: Boy, was I wrong here! Since I began viewing the planets regularly, there are as many "good seeing" nights as poor ones.

Altogether a bad night for star tests and planetary observation. But, once Luna set a passable night for deep sky...

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The Seeing Improves

On this occasion, I repeated many of the observations done the previous night (documented above). However, the seeing was much better for planetary observation. And in staying up late (to view the planets over an extended period of time) I got a chance to view M42 in Orion. In addition to having first light fall on Argo from M42, I tracked down the double-cluster (NGC 884&869) between Perseus and Cassiopeia. Observations, once again, took place at the local elementary school grounds.

Since Saturn was higher in the sky than Jupiter, I spent about a half an hour confirming the details of observations done earlier in the season (under good seeing conditions). No surprises presented themselves, although I spent a great deal of time confirming the limb-delineation I'd seen earlier and came to the tentative conclusion that I was seeing the planets terminator along the extreme western-most edge.

Upon completing my Saturn tour, I turned the scope on Jupiter. Since I had yet to take the time to really "see" Jupiter (in as much detail as possible), I put in a lot of time acclimatizing to it. After a while I started to notice features previously undetected. For instance, I saw irregularities in the northern edge of the northern equatorial belt (the NEB). I also saw a much narrower (and fainter) belt running parallel to the equatorial just to the south. In scrutinizing the south equatorial belt, I saw that it was actually two belts in parallel very close to one another. In addition to the SEB and NEB, I noticed both a northern and a southern temperate belt. Both belts were widely separated from the corresponding equatorial belts. Finally the polar regions of the planet were visibly duskier than the bands between the various belts.

Of all these features, I would say that the SEB and NEB are most easily discerned (followed closely by polar darkening). Irregularities in the northern edge of the NEB were slightly easier to spot than the fact that a low contrast sub-SEB belt ran parallel to it. The splitting of the SEB, and evidence of the two temperate latitude belts were slightly more difficult to make out than the splitting of the NEB.

These observations of Jupiter all need to be confirmed at later dates. The low contrast of all features casts doubt on everything recorded above (with the exception of the general existence of the NEB, SEB and polar darkening).

NOTE: I have since purchased a barlow lens to extend my maximum magnification from 200, to 210, 360X (and beyond). In addition I picked up the Orion Telescope "Starter Pack" of filters. These tools, along with some excellent seeing over an extended period of time, should allow me to be more definitive about SEB and NEB splitting plus the appearance and positions of the two temperate belts.

With my planetary observations behind me, I decided to track down the famous "double cluster" in Perseus. In so doing, I found that the location of the cluster actually falls between Cassiopiea and Perseus. I also noticed the astounding fact that Charles Messier had not included them in his famous list of comet teases. How could he have possibly missed this pair?

I'd seen the double cluster before at a star party (through someone else's scope). The pair is quite popular with the deep-sky crowd. I myself prefer globular clusters, but this pair of open clusters has enough compactness and large enough stellar population to intrigue me -- so I decided to dote on them for awhile.

Obviously, the preferred approach to this pair is to try and get them both in the same FOV. My best shot at this is a 35mm Ultrascopic (50X with 60+ arc-minutes of apparent field). So I can take in about 1 degree circular with this eyepiece. After quickly tracking down the pair through the finder, I found that I could easily get the center of each cluster in the same field. (However this approach truncates their respective outer regions east and west.)

In viewing the pair it was clear to me that the two clusters are siblings. Both, no doubt, were borne of the same extended low-density nebular womb -- some time in the not too distant astronomical past -- far from the galactic core where the globular clusters prefer to roam...

The western sibling (NGC 869) seems to have a numerical advantage in both stars and magnitude. Two bright twin stars dominate its central core (separated by about 5' of arc). As I view other stars in this cluster it seems to me that "twinning" is a fairly common theme. Various stars similarly close (or closer) seem to pair up in brightness and location. (Perhaps this cluster should have been placed in Gemini? If so, I'm sure "The Comet Ferret" would have most certainly added it to his list.)

The eastern sibling (NGC 884) is dominated by a single bright star near it core. The twinning pattern is also seen here (yet without the presence of a pair of bright core stars) the mind is less likely to play the twinning game. This cluster gives the general impression of a wide arrowhead in flight. The tip of the arrowhead is pointed at the heart of its eastern sibling. The eastern cluster itself gives the appearance of a "swooping bird of prey", the arrowhead of the western cluster pointed toward its two bright eyes. Dark bands wend their way through both clusters. This suggests that the "birthing -twinning" process is not yet over. No doubt dozens of new stars will eventually give radiance from these dark bands -- adding to the several hundred magnitude 8 and dimmer stars that make up this splendid pair.

The Hunter was now well clear of the southeast horizon. It had been many years since I viewed M42 through a small telescope. Needless to say I was eager to do so.

Glorious! Now here's a nebula. No gauzy, ill defined gray patch this. Here was an obviously "bright, white" cloud. filling the entire field with radiance. Ensconced in this cloud was the trapezium (easily resolved at 50x). It's four stars of descending brightness giving a sense of angularity and depth. A short swatch of stars guided the eye toward them. The dark fringes of an intervening nebula below them and to the right. Surely, I'll have to revisit this sight and give it the kind of detailed attention that it deserves.

As Saturn approached the zenith I packed up the scope and went a homeward bound.

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There's a lovely open hillside about 5 kilometers away overlooking my hometown. From the yard I can train my telescope on it. Among the objects I can focus on is a snow fence. A snow fence has alternating gaps between wooden slats. At 180X the gaps are visible but nothing much can be seen through the openings. I planned to test what (if any) benefit I might have in seeing fine detail when bumping up the magnification using the snow fence as a target. The first problem I encountered was the lack of focuser travel in the Argonaut. This made it impossible to use the barlow in the normal 2x configuration. To achieve focus I was going to have to use it in the 3x configuration (before rather than after the star diagonal). Using 2x I would have had the following magnifications at my disposal:

Instead, I now I have something more like this:

Initially I was skeptical about ever pushing a 6" scope to 90X per inch aperture. However, to be thorough, I made a series of observations to get a sense of just how bad things could get. Conditions for my day light test (using the snow fence) were outstanding. Even at 180X it is obvious when conditions are poor -- the air "boils" around the fence making things quite indistinct in the background. This was not the condition I saw at this time. The air was still -- with only a hint of haze. Things were in place to determine just how much of a problem high magnification was in and of itself (as opposed to atmospheric conditions).

I started out with the 25mm at 3x and compared this to previous views with the 10mm at 180. First the 25mm at 3x was indeed showing larger images than the 10mm straight. So the configuration I was using probably was a true 3X. (Barlows are tricky. You can't assume that 2x and 3x are precision multipliers -- much depends on the distance of the eyepiece from the barlow lensing system.) Next, it was obvious that I was able to leverage off the better eye relief of the 25mm eyepiece. (Eye relief on the 10mm is poor compared to the 25mm. The barlow in itself did not improve the native eye relief of the eyepiece.) I also noticed some field flattening. Again, I noted that image brightness was slightly poorer (due to both the increased magnification and the additional three elements added by the barlow to the five already in the eyepiece.) Finally it was clear to me that an additional 16% gain in image size did allow me to view objects more plainly through the snow fence gaps.

I repeated the above tests using the 15mm and 10mm oculars. At no time did I see a magnification cliff. Things just kept getting larger and darker. The gap in the fence got larger, more detail was acessible to my eye. Wow! But would this hold up in the night sky?

NOTE: The next day I repeated the above test sequence. The snow fence looked bad at every power. There was a lot of atmospheric boiling. More power simply meant things got darker and murkier -- there was even a loss of detail above 210X. So once again, I confirmed for myself that seeing is the fundamental factor effecting the performance of excellent optics...

As the sky darkened, I took the opportunity to test night sky performance. I did this by turning the scope on Epsilon Lyrae. An easy split at 150, more gap at 210X, still more gap at 360X (with the beginnings of an "airy disk" quite apparent) and finally at 540X. Double wow, good optics plus good seeing rules!

NOTE: At 360X and 540X I was able to distinctly see two additional stars between the brighter four components of the double-double. Therefore, in addition to the 9.5 magnitude star forming a triangle with the two binary components, I was also seeing the 12.0 and 12.5 magnitude comes that turn this true double binary into a line of sight septet. At lower powers, I had only seen the 12.0 magnitude with hints of the 12.5 comes in the darkest portion of the night. Now here it was late dusk and I was confirming all seven stars. In this way I demonstrated that higher magnification does, in fact, reveal dimmer stars.

Unfortunately, before it got too much darker, low clouds were moving in. With the moon rising in the east, I began high power tests using my filter kit and barlow combination. Atmospheric boiling was visible at all three higher powers. The out of focus effect of increased magnification showed itself obviously. However, details visible at 210X were also visible at 360 and 540 so other than the annoyance of seeing things less clearly there was no real problem with using the higher powers (as long as you have a good clock drive...). I then brought out a succession of filters at 540X for testing. These consisted of the following types:

I started with the yellow. It did appear to allow additional foreground details to be made out -- but for some reason I did not particularly care for the aesthetic affect. The red seemed to make things appear "blurier" (aesthetics were even worse). The green allowed off-axis background features (such as lunar rilles) to get my attention. (I didn't even notice one particular rille until I dropped in the green filter although I could find it with all the other filters -- and without one -- once I knew what to look for.) The blue seemed to improve the sense of clarity and focus.

During the test I used the maria-filled crater Plato as a target. The only feature I could make out within it was what appeared to be a slight central dimple? crater? and even this not particularly well... (Plato was well away from the lunar terminator at the time of this test.)

With my initial Luna tests completed, I used the finderscope to penetrate the hazy clouds to find Saturn. It was kind of neat to see it so huge (dim, and blurry) at 540X. Cassini's division was suggested to my eye at all magnifications. But I never got to see the planet and ring system as anything other than a low contrast "glow" through the low clouds and made no real tests with the filters. Later in the evening I stepped out and found Jupiter high in the sky. Once again, I enjoyed seeing a disk the size of a quarter and on occasion I thought I saw some detail in the SEB. But once again, I basically needed more light to better exploit the high magnifications employed.

Conclusions: Use all the magnification you can get away with (on the moon and planets) depending on seeing conditions. If you can't see anything at all at 180X you probably won't see anything more at 360 or 540. Filters may be useful to enhance low contrast details. But more testing is needed to determine which filters, under what conditions, and amount of improvement possible.

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Putting on the Colored Shades

It's now 11:00 pm. I spent the evening continuing my experiments using high magnifications and colored filters. The method employed was to follow the planets as they rose higher in the sky. This emulated a continuous series of improved seeing conditions. With the planets low near the horizon my sense of "seeing" conditions was stability: 3/10 and transparency: 4/10. As the evening progressed, conditions culminated with stability rising to 7/10 and transparency perhaps the same. Some dewing of the meniscus occured (especially as the planets rose higher and water vapor could more easily deposit itself). So effective transparency probably fell off to less than 5/10 once stability hit it's peak.

Preliminary Checks:

NOTE: Unlike the evening before however, I could not see the 12+ magnitude comes of Epsilon Lyrae during my late dusk observations.

Planets Low / Poor Seeing Emulation:

I then stepped through all my filters. None of which did anything to improve the view of details. All basically "dis-improved" the image.

It took about 45 minutes to complete my Saturn series. Meanwhile, Jupiter cleared the trees to the east and was in a position to repeat the "poor seeing" Saturn test series. At both 210 and 360X the North and South Equatorial Belts were perceptible. Polar darkening and planetary oblateness were are also present. At 540x the SEB was difficult. The planets body was just too blurry. It also danced around in the eyepiece. The filter series offered no real improvement in detail. Only the blue filter showed any promise and that for aesthetic reasons. (The yellow of the planets body is filtered out and takes on a nice creamy white -- a good look for Jupiter.)

NOTE: The blue filter did nothing to improve Saturn's aesthetics due, no doubt, to Saturn's lower surface brightness.

Planets Higher / Fair Seeing Emulation:

In looking over my field notes I can't find anything definitive about Jupiter at this point. I recall that it was about this time that 210 and 360x would begin to show irregularities in the shape of the NEB. Occasionally, I would also see the NEB split in two -- but not the SEB. At 540x, the SEB was present and irregularities in the shape of the NEB were hinted at. Again only the blue filter offered any hint of improving detail (at 210 and possibly 360x) and, of course, aesthetics.

Planets Well Up / Good Seeing Emulation:

Turning to Jupiter, I found that, once again, everything visible at 210X was perceptible at 360 and 540x. The 210x view was the most aesthetically pleasing. Like Saturn, Jupiter was etched into the dark background of space at that power. The NEB and more difficult SEB were easily split into two bands each. No temperate belts were visible, however. (I am beginning to doubt that I have ever seen them at all now.) The use of the blue filter added nothing to the perception of detail -- but now, even more so, I liked the look of the "Blue Gas Giant".

Conclusions:

Finally, 180X is really not enough for Jupiter (although it works well enough on Saturn). The 210(?)X I'm getting with the 25mm / 3x barlow combination shows better contrast in surface details when the seeing is above average. It also offers far superior eye relief, a flatter field, and a darker sky background. This is the combo you would want in place during star parties featuring the planets. Otherwise, 360X is the "go to" default for this scope -- seeing conditions permiting.

NOTE: As a result of later experience (viewing both Jupiter and Saturn through the 150mm MCT), it became clear that Jupiter is far less forgiving of "hyper-magnification" than Saturn. I now tend to view Saturn at 540X and Jupiter at 210X during periods of good to excellent sky stability. If the sky also happens to be very transparent (dark) there is value going to 360X on Jupiter. (But the coincidence of both dark and stable skies is rare.)

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Confirmation!

It's now 12 midnight. Just finished observations of Saturn and Jupiter under almost perfect conditions (except it was cold out there, brrrr...). Transparency: 5.0, Stability: 9! Why 9? Because I was able to do this evenings observations at 90X / inch of aperture (540X!).

And under so much magnification what did I see?

Jupiter:

Initially all that was perceptible to me (other than the unusual steadyness and sharpness of the planet's limb) were the two equatorial bands stradling the central bulge of the planet's girth. After a few seconds I felt the familiar "shift" in my perception. (This shift is generally followed by a significant improvement in my ability to perceive low contrast detail.) With the shift I became aware that the Great Red Spot was very close to transiting across Jupiter's central meridian. I also saw that the opposing equatorial belt was accompanied by a low contrast and much thinner paralleling belt. I decided that this would be a good opportunity to solve a few personal planetary mysteries.

One question I had in mind was whether or not the north and south temperate belts were actually visible in this scope (as I earlier documented). And if the belts were visible, why wasn't I able to detect them during other times of good seeing?

The answer became clear after a few moments of detailed observation. The two temperate belts appear to mark the frontier between the brighter equatorial region and the duller polar regions of the planet. So, depending on the condition of Jupiter's atmosphere (its weather) - the temperate belts might simply "blend in" with the polar transition dropping out of my scopes ability to reveal low contrast detail.

A second question also needed explaining. When the two equatorial belts appeared to "split", was there really two distinctly separate belts or was there just a brighter region between two parts of a single belt?

Under the superb seeing I was experiencing, I got the sense that the non-red spot equatorial belt (NEB) actually consisted of two separate regions, while the red spot belt was a single region separated by a divide of lighter coloration. I drew these conclusions based on the following observations:

• Detail in the red spot embedded belt (SEB) was denser and more conspicuous further away from the equator.
• Detail in the NEB was more conspicuous closer to the equator.

It also appeared that the cause of the "sothern" split was the red spot itself. This became clear when I notcied that the Red Spot looks like an "island" of darker material surrounded by a narrow lane of bright material. The band closer to the equator actual sweeps down below the Red Spot (without touching), swoops around and joins up with the more robust portion of the SEB east of the Red Spot. Only before the Red Spot is the separation of the SEB perceptible. After it, I could see only a single "kneady" wreath of indecipherable texture continuing along toward the planet's eastern limb.

As for detail in the NEB (the non-Red Spot equatorial belt), I could make out a slight disturbance below and to the west of the Red Spot. Just before the Red Spot, the NEB narrowed up a little and resumed a more or less continuous line of termination. I also noticed that the gap separating the NEB from it's paralleling belt was about the same as the gap between that belt and the South Temperate Belt. (The gap between the SEB and the STB is about the same as that between the NEB and NTB -- basically much larger.)

All four of Jupiter's Galilean satellites show discs at 540X. However, the disk effect is somewhat obscured by irradiation into the night sky. No detail is perceptible on these disks -- absolutety none whatsover. However, the disks are perceptibly of differing sizes when compared with one another.

Saturn:

• Under detailed scrutiny, does Saturn's SEB split into two like the NEB on Jupiter? Or is it more like the temperate belts on Jupiter. Well the answer is inconclusive. I did, in fact, get a sense that the SEB (no NEB is visible due to the presence of the ring system) could be double. However, it appeared as though the SEB "blends into" the duller polar region. Since Saturn is colder than Jupiter, it has a less complicated system of belts, (I suspect only an NEB and an SEB.) Since Saturn is much more distant, what little detail in the belt system that exists is very difficult to makeout.
• The more important question in my mind about Saturn is whether or not the Encke Division in Ring A "exists" for such a modest telescope. In the past I have noticed what I called "striations" in Ring A (at 180X during exceptional seeing). Basically, Ring A gives the appearance of being "discontinuous". But is it possible to actually see a discrete "discontinuity" (like Ring B's frontier -- the Cassini Division)?

Well if there ever was a time to determine the answer to this question it would have to be tonight (or a night like it). Saturn is near opposition. It's ring system is in full presentation. The seeing was as good as anyone has the right to ever expect.

So what did I see?

Well, briefly during periods of greatest visual acuity, and atmospheric stability I saw a very obscure, and quite narrow echo of the Cassini Division some distance away from Cassini closer to the void of space than to Cassini's Division itself. This faint echo of Cassini was barely perceptible and only where Ring A was furthest from the planet on the western lobe of the ring system. To check my observation, I had my eagle-eyed son tell me if he saw any such "echo" and where its was located. He said he could see a short extremely narrow dark lane closer to the frontier of Ring A than it was to the far more obvious Cassini Division. But even with this agreement, I remain unconvinced that I saw it -- definitively.

NOTE: In double-star resolution work I tend to avoid claiming any particular split as a success unless I have a clear separation of primary and secondary -- no "guesswork" allowed.

Some colors: Saturn's sash is basically a duller version of the same brght yellow seen band seen on Jupiter. It's polar regions are also a duller version of the blue grey seen at Jupiter's poles, but Saturn's "poles" begin MUCH closer to the equator. The inner dusky ring (Ring C) is smokey grey transitioning to black. There is no visible division between Ring C and Ring B. Ring C is most easily made out where it crosses the body of the planet (to the south). In good seeing and at higher magnifications using an optically correct 6", it can be seen transitioning from Ring B to the black void separating the body of the planet from the ring system. Ring B is bright yellow. It appears solid and continuous to the eye. Even at 540X, Cassini's Division is very compact and black. It marks the break between the yellow of Ring B and the striated "lavender" of Ring A. Ring A does not give the appearance of abruptly breaking off into the void of space. It seems to "bleed" into it at the edges. The Encke Division is about 2/3rds of the distance across Ring A from Ring B. It, as described above, is notoriously difficult to make out, due to its narrow width and the lack of contrast generally seen in Ring A.

I could not see the shadow of the planet on its rings. I suspect this is due to the fact that it is very close to opposition (rising as the Sun sets). On previous occasions I've noticed a dark delineation between the eastern edge of the planet and the ring. (By eastern, I mean the leading edge of the planet as it rotates on its own axis, but visually the limb leading the planet across the sky -- due on the Earth's rotation.) There is no reportable detail visible in the planet's atmosphere which corresponds to Jupiter's Great Red Spot. Unlike Jupiter's moons, none of Saturn's even hint at a disk.

NOTE: Some glare was present around both Jupiter and Saturn during my observations. I had to frequently coddle my eyepieces in the palms of my hands to free them of dew. The meniscus on the OTA was also hampered by some dewing as well. The optics are not particularly clean -- especially the mirrored star diagonal. (The diagonal is not a better representative of its kind in any regards.) I was fortunate to have a clock drive -- otherwise I would not have been able to handle 540X without constant adjustment -- and frequent irritation at losing the detail. I also had to deal with flotsam floating around inside my observing eye fluid. Flotsam is especially distracting at high powers, and low contrast. I get the sense that not everyone is equipped to deal with planetary observations of the type I've discribed above. If you simply must view planets at high power and want good contrast between details spend big bucks and get a six inch refractor and build a small observatory to house it in. Shouldn't cost you more than 10 or 15 thousand dollars...

What I will always remember of this night is the way both planets looked in the eyepiece. I felt like I was looking down into a deep, dark, well of clear, cool, peacefully calm, water. Meanwhile, over my shoulder rose the glowing images of exotic luminous worlds which I could only see by reflection on the water's mirror-like surface. Of such experiences do we reconstitute ourselves in infinity.

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I had a definite plan in mind for this evening's observations. (And fortunately God didn't laugh.) Basically, the idea was to determine whether or not there was any real value in using "filters" to enhance the view of deep-sky objects (now that the moon isn't hogging up so much of the sky) and the planets.

Deep Sky:

I started pretty early (around 6:30pm while the sky was still darkening) and made a quick assessment of the seeing conditions. Turning to Epsilon Lyrae, I found that it could not be cleanly split at 120X but that it was most definitely a double binary. By experience I know this means that atmospheric stability is about average (5/10). Under such conditions I would expect to have a difficult (but not impossible) time making out Cassini's division in Saturn's rings and I would be limited to 210X when viewing the gas giants later in the evening. (When I would shift over to filter tests on Jupiter.) But first "deep sky" and the associated OIII filter test program...

After assessing the seeing, I made a quick check to roughly estimate how much limiting magnitude is lost when viewing the night sky through an OIII filter. I know from consulting star charts that the Epsilon Lyrae "double-double" actually includes 9.5, 12.0 and 12.5 comes within the same basic region of space. (There are others but these are good test subjects.) I found that as the sky darkened I could make out the 9.5 and 12.0 magnitude comes -- but not the 12.5 magnitude star. On installing the OIII filter, I could still make out the 9.5 magnitude star. (This looked slightly brighter than the 12.0 magnitude attendant had.) So under current conditions (with a naked visual limiting magnitude of 4.5), I could just detect 10th magnitude stars with the OIII filter in place and 12th magnitude stars without. (Generally speaking my 150mm 34% obstructed Orion Argonaut/Intes MK-67 gives me a plus 7.5 magnitude boost over naked eye visual limiting magnitude.)

With the OIII filter still in place I quickly located M57. Even at 120X (and during relatively poor sky transparency -- 4/10) I had no trouble locating it about 1/3 the way between Beta and Gamma Lyrae. I found it farirly straightforward to distinguish the darker interior of the smoke ring. I also verified that the roughly east-west ansae were darker than its north-south flanks (but lighter than the center). I could also detect the fact that the southern flank was marginally brighter and slightly wider than the north. Removing the filter made no difference to my eye in making out these same generalities as to shape and brightness. So far, the use of an OIII filter was not much of an advantage in a telescope of this aperture, focal ratio, and large central obstruction ratio.

My next test was to see if, with an OIII filter in place, I could still locate a moderately difficult object that was not expected to be enhanced in any way by selective narrow-banding. The obvious choice for this was M56, a relatively dim globular cluster of the 8th magnitude about 2/5ths the distance between Albireo and Gamma Lyrae. (M57 is listed as magnitude 9.7 but its smaller size suggests a surface brightness comparable to the larger M56.)

After some searching, I was able to locate M56 using my 35mm (50x) ep. Under current observing conditions (less than average transparency) it was just barely possible to make out M56 (as a fuzzy star) in the 7*35 finderscope. (And this only after I had found it by sweeping the star fields in the immediate area using the main telescope.) Since the light from globular clusters is broadband, there is no advantage (in fact appreciable disadvantage) to viewing it through the filter. So having found it, I switched over to the 15mm (120X) ep and gave it the kind of scrutiny I had just done with M57...

M56 is obviously larger than M57 (perhaps by a factor of 3 under the conditions I was viewing it in). It is also far more spherical. Unlike M57 it has no defined edges (although the north quadrant appears to more sharply drop off into the darkness of space than the "rounder" south quadrant). Globularity seems to extend a little further along the east-west axis (than the north-south).

Like most low surface brightness objects, the best views of M56 occur when you first acquire it with the eye, or when you flit the eye about in the eyepiece, or when you view it through averted vision. Unlike the brighter globulars (M13 & 22 for instance) no amount of patient observation will ever reward the owner of a 6" telescope with the much sought after 3D effect of resolution into hundreds of stars. At best you will see the scintillation effect of a dozen or so member (and brighter line of sight field) stars followed by an apparent "granularity" when the eye settles down to viewing it directly. Perhaps under excellent deep sky conditions two dozen or so stars may remain persistently apparent in a 150mm but "seeing" precedes believing for this particular object.

Now on to my final test of OIII enhanced perception: The Veil Nebula(!?). There is so much "nebulosity" in the area south of Epsilon Cygni that every time I attempt to find the famed "Veil Nebula" I am completely afflicted by doubt about identifying it! (Will the real Veil Nebula please stand out?) Meanwhile, tonight's "Veil Nebula" was a lovely arc of stars interspersed by obvious reflection nebulosity somewhere in the 52/41 Cygni area. To help others in finding what I am referring to here let me provide a brief description...

Once you find the southern tip of the Cygnus cross, locate the first 4th magnitude star that drops down from Epsilon Cygni (parallel to the backbone of the cross). Center this star in a low power ep and look east until you identify a parabolic arc of stars some half-degree in length. You can verify this particular "Veil Nebula's" identity IF you also notice a 7th magnitude star taking up a position that corresponds to the end of an arrow's shaft, if that arrow was placed against a string connecting the two ends of the parabolic arc of stars comprising the bow.

If you find this configuration, you will see that many of the 7.5+ magnitude stars making up the "bow" display a wispy nebulosity around them. Under poor transparency conditions (like I experienced this evening), little of the nebulosity actually interconnects the two dozen or so stars together in the parabola. UNLESS you install an OIII filter! With the filter in place, most of the stars are interconnected by pale luminosity. $100 narrow band OIII filter vindicated!

Jupiter:

I wrote the above while waiting for the Saturn and Jupiter to ascend. Around 9:30 I headed out into the "Northern California Cold" to resume my filter checks -- this time on Jupiter.

Took a quick look at Saturn -- strictly for stability-checking purposes, of course. Cassini and the SEB were clearly visible. Things had improved over earlier. I mentally ticked up the stability rating by a notch (to 6/10). Some of the haze had dissipated so I indexed the transparency rating up to 5/10. Nice solid, slightly than better average for the Jupiter series.

Broke out the 3x Ultrascopic barlow along with the 25 (210X) and 15mm (360X) Ultrascopic eps. I find that two eyepieces are essential (not for filter tests) -- due to dew. (One ep can be de-fogged by ensconcing its cold barrel in your not so warm hand while the other remains in the OTA for viewing.)

First views of Jupiter were sans filtration. The SEB and NEB were easily visible. Irregularities in the edge of both equatorial belts (but especially the SEB) were noticeable. Hints of intra belt turbulences were suggested but not explicit. Both the SEB and the NEB were seen as clearly twinned. Four belts were accessible with no hints of the two temperate belts. Polar darkening also visible. The four Galileans were queued up linearly in groups of one and three along the equatorial plane. Tiny disks of various sizes besmirched with "skyglow" were perceptible.

Based on this Jupiter view I mentally broke my observational goals up along the following lines:

• Which filter(s) (if any) would assist in showing the two temperate belts?
• Which would tend to better display irregularities in the outlines of the two equatorial belts?
• Which would improve the sense of texture and detail within the more distinctive regions of the equatorial belts?
• Which would tend to better separate the two divisions of the twinned equatorial belts?
• Which would display the texture of the polar regions to best advantage?
• Which would give the most pleasing aesthetic view of the planet as a whole?

Under the 6/10 stability conditions of the evening, it was obvious that the 25mm/barlow configuration (210X) gave the best views of the planet. 360X was not showing very good limb delineation or contrast on this particular occasion. (There would be no 540X observation this evening.)

I started with the yellow filter (#15 Deep Yellow) 210X. Aesthetically the view was poor. (Too much yellow already in Jupiter -- all I could think of was lemons.) In addition to the aesthetic, the yellow seemed to deprecate the detail visible within the EBs. Overall, yellow was a dis-improvement. Another observing session will be needed to determine if it has anything worthwhile to offer as a Jupiter image enhancement tool...

Before switching over to #25 Red, I reviewed the appearance of the planet without filtration. By this time I began noticing a hint of the NTB in the ep. (This was not suggested during use of the yellow filter just previously.) Use of the red filter immediately reduced the surface brightness of the planet. Because of this the equatorial belts stood out fairly dramatically. However, there was little additional detail present to the eye. (Although my scribbled notes indicate a possible improvement in making out the outline of the EBs with another possible improvement in perception of intra-belt texture.) The red filter also seemed to improve belt contrast even more at 360X under the current observing conditions. The red filter did not reveal the NTB so it did not appear to bring out elusive detail.

Overall seeing of the planet began to peak just as I began the #58 Green filter tests. The NTB was more readily apparent (without a filter) and hints of the STB were also seen occasionally.

The use of green cleaned up the edge of the planet. (It was not possible to fully relieve the eyepieces and barlow lens of condensation, so internal light diffusion was a constant problem.) Although green reduced surface brightness considerably (like red) it did a better job of revealing general detail. Green was the only filter that enabled views of the NTB. It also enhanced the sense of surface "mottling" associated with the planet's piolar regions. So Kermit, Be Proud!

By the time I moved on to #80A Blue, the filterless image of the planet began to deteriorate due to condensation on the OTA meniscus.(Even with a dew cap.) Previous observations had already proven that blue gives, by far, the most pleasant aesthetic look. This it does this without undermining the visibility of any particular feature type.

Conclusions:

Owners of 150mm telescopes may consider adding some filters to their observing kits. Those with smaller scopes may want to consider the fact that filters do not add anything to what is already present in the native image. (Theoretically, we all recognize that filters block some frequencies of light so that other frequencies can better impact the eye.) If native luminosity is already low, there is no advantage to using a filter as an image enhancer. The value of filters does seem to increase as light gathering capacity improves. Larger apertured scopes will no doubt profit more from filters than smaller ones. However, filters may still be of advantage while using imagers or long period photographic exposures even in smaller scopes.

For those of us using 150mm reflectors (or 125mm or larger refractors) certainly the filter types described above may offer some visual advantages. Personally, I'm pleased with the effect of an OIII filter when viewing reflecting nebula. The aesthetic effect of the medium blue filter on Jupiter can be satisfying, while green is probably best overall (even if less aesthetically pleasant) at enhancing low contrast detail and "sharpening up" images.

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With Lyra and Cygnus beginning to dissappear to the west, I'm feeling the need to finish up my initial round of observations of this lovely portion of the sky. Soon, I'll also need another close binary to consult when determining seeing conditions. So before losing Epsilon Lyrae, I wanted to find a candidate for the role and get a sense of how well the two star sets compare over several observing sessions.

Hitting the books, I came up with Iota Cassiopeia. This fine tight triple consists of 4.7, 7.0 and 8.3 magnitude stars with separations of 2.5 and 7.3 arc seconds. The separation distance of the AB pair is roughly as tight as the average of epsilon 1 and epsilon 2. However. the brightness differential is greater, so I expect that splitting AB will be slightly more difficult than Epsilon Lyrae.

LATER NOTE: Since my scope was packed from a Saturday star party, I took it up to Boulder Creek Elementary School on Sunday evening the 19th. While at the school, I made some more or less "definitive observations" of both multiples. On that occasion, I was able to get a "clean split" of the Double Double while having a slightly "dirty split" of Iota Cassiopiae. Even allowing for the possibility of differing seeing conditions across the sky, it's pretty clear to me that a clean split of Iota indicates slightly superior sky steadyness to a similar split of the Double Double.

I had several goals for this weekend's observations. First, I hoped to determine the actual location of the "Bow Nebula" I found during Thursday evening's filter testing. I also wanted to revisit M56. I especially wanted to explore the "Veil Triangle" region (between Epsilon, Zeta and 52 Cygni). Finally, I planned to take a quick look at Jupiter and Saturn, make an assessment of the seeing, and begin paying more attention to their respective moons.

I started out (as usual) by assessing the seeing. From my backyard viewing location (in town) I am fortunate to be able to make out the Milky Way band through Cygnus. This is about what I experienced this evening (although things began to deteriorate when a nearby heating system kicked in and started spewing exhaust). Earlier, however, I was able to get a clean split of the Double Double, so at least the sky was reasonably steady. In addition, the 12.0 magnitude star (come) between E1 and E2 was also directly visible, so some "deep sky" reach was available.

On Sunday evening upon returning from my elementary school viewing session I made a quick check of backyard seeing conditions. Essentially, when viewing out of my backyard, I am losing at least .5 magnitude in threshold visual magnitude. This is primarily due to light pollution, but also because the school is several hundred feet higher in altitude.

After splitting Epsilon Lyrae at 120X, I quickly turned my scope on Iota Cassiopeia. As expected, all three stars resolved (at 120X). I made a quick check of colors: Gold, blue, and lavendar (in order of magnitude). So far, so good.

I then turned the scope on M57. My hoped for 12.8 magnitude field star was just visible (by slightly averted vision). (This foeld star extends from the northern side of the "Chalice of the Ring" toward the Ring itself. The "chalice" asterism itself shares the center of the field with M57 at low powers (50X). It looks like a broad "Y" consisting of 6 or 7 stars with the mouth of the "Y" facing the planetary nebula.)

From the school locale Sunday evening, the 12.8 magnitude field star was directly visible, while a still closer (on the opposite side of the ring) 13.1 magnitude star was detectable with averted vision.

M56 was easier to find this evening. I decided to see if my 10mm 180X eyepiece offered any advantage in resolving stellar components. Whether due to the additional magnification -- or perhaps a slightly darker sky -- I immediately noticed that both the "scintillation effect" and "granularity" were more directly visible than the night before. In addition, averted vision pretty much guaranteed some resolution. Based on this, I am now better able to anticipate star resolution in globular clusters. Generally speaking, any reasonably well positioned globular cluster with a magnitude of 8.0 or less should be resolvable into at least some stellar components (in a 150mm scope). Slightly dimmer clusters (such as M56) may show some stars on dark nights (or using averted vision). If true, there should be at least a dozen globular clusters accessible from north temperate latitudes that will reveal member stars to a 6" scope. While viewing M56 on this occasion, I also confirmed the basic shape of the globular as discribed in the previous evening's notes.

On Saturday the 18th, I attended the Santa Cruz Astronomy Club (SCAC) Star Party at the Bonny Dune observing site. At an altitude of 650 meters -- and an initial 5.5 limiting visual threshold magnitude -- I was able to directly view at least a dozen M56 components in the 6". This more or less confirmed speculation with respect to resolving dimmer globular clusters under dark and steady sky conditions.

This evening (at the school locale), with a limiting unaided stellar threshold of 5.0, I was able to make out a dozen or so M56 stellar components by simply shifting my vision slightly away form the cluster. It's pretty clear that limiting threshold magnitude has a big impact on whether or not and just how you will be able to resolve any particular globular cluster.

On Thursday evening I found a nice area of stars and nebulosity near the "Veil Nebula Triangle" in Cygnus. At that time, I used the nebulosity (which I call the "Shining Bow Star Arc") to determine how effective an OIII filter could be at bringing out detail. At that time I wasn't quite sure where the arc was located. On Friday evening, I carefully aligned my scope to 41 Cygni. 41 Cygni definitely lies near the western foot of the bow. Once found, I pulled out the OIII filter and made a brief inspection. It appeared to me that in larger scopes -- or on darker nights -- the nebulosity surrounding the star arc would probably "connect up". So I now look forward to revisiting the arc on an ongoing basis in hopes of getting a better sense of its shape and detail.

At the SCAC party, I revisited the Shining Bow Star Arc and inspected it under the better conditions there. Some nebulosity appeared to be associated with the arc. I asked a more experienced member of the club to look it over on the off chance that I had mistaken "star glow" for nebulosity. That member (Derrick) tentatively agreed that some nebulosity was present. More observations are needed before this deep sky gem can be fully characterized.

At the school this evening, I made a quick check of the arc at 50X with an OIII filter. The nebulosity did not appear as extensive as I thought it was. Perhaps more magnification is needed. This issue is going to hang around for a while...

Veil Nebula Triangle:

I began my exploration of this region by aligning my finder on Epsilon Cygni. I then slewed due south about 3 degrees until my crosshairs intercepted 52 Cygni. With 52 Cygni centered in the finder all I needed to do was inspect the view in the main telescope and voila -- no nebulosity. OK, so install the OIII filter, then look. Nebulosity!

The Planets

Despite the promise of good seeing (inherent in a clean split of the "Double Double"), my first views of Saturn (at 210X) later on Friday evening were uninspiring. Cassini and the equatorial belt were present -- but the division was not nearly as razor-sharp as I had seen it in the past. After admiring what could be seen, I made a quick count of "attendants" (5 close to the planet, 1 more distant) and turned the scope on Jupiter, (knowing there would be little of note there as well -- but still looking forward to whatever could be seen).

At Saturday's star party, high thin clouds started moving in and made continued deep sky activities futile. (This occured about an hour after dark.) Air steadyness was not effected so we turned our scopes on the planets. With 1500 more feet of the Earth's atmosphere below me than in Boulder Creek (altitude 500 feet), planetary views were outstandingly stable, (although some contrast was lost to thin clouds). During observations of Saturn, all three scopes (150, 200, and 250mm) were able to reveal the Encke gap at the ansae of Ring A about 2/3rds the distance away from the Cassini Division. This was only possible at 350-400X in the various scopes (but not at 200X). All experienced observers agreed that we were in fact seeing a small portion of the Encke Gap.

On Friday, Jupiter displayed it's ever-present two equatorial belts along with some hint of edge-irregularities and embedded detail -- but the split into two sets of EB's was not as obvious as in past views, and neither of the temperate belts were even hinted at. Checking the moons, I noticed a 1 to 2 configuration (with the two brighter moons trailing Jupiter across the sky). All moons displayed small disks at 210X, but some boiling was present over the satellites and on Jupiter's limb. From the lack of lunar shadow along the equator, I suspect that the fourth moon was behind the planet at the time of observation.

On Saturday (at the star party) it was again made abundantly clear to me that good optics and excellent seeing conditions are the quid pro quo of planetary observation. In cycling through the 150, 200 and 250mm scopes (all catadioptic) the main difference in the various views (all at approximately 400X) was the brightness of the image -- not actual detail seen. For example, the 150 and the 250mm scopes were both able to display the NTB. (None revealed the STB.) Jupiter's view in the 250 was visibly brighter and more contrasty than in the 150. (The view in the 200mm was not appreciably brighter however.) Festoons and irregularities in Jupiter's equatorial belts were visible in all scopes. But other than image brightness and contrast, there was no real advantage of one scope over the other. (The eye just had to work harder in the 150.)

Conclusion:

I now have a clear sense of how to find and what can be seen of the Eastern and Western Veil Nebulae. The expense of an OIII filter is now justified based on the observations leading up to this clarification. The location of the "Shining Bow Star Arc" is now confrimed. At magnitude 8.2 (and 7 arc-minutes angular size) M56 has proven that at least some stars are resolvable in a 150mm scope. (Because of this, it is likely that there are at least a dozen or so globular clusters that will reveal something of themselves to a 6".) I now have a new test double to consult for determining air steadyness. Head to head comparisons with 8 and 10 inch scopes of good optical quality has shown that a 6 inch scope of diffraction-limited optical quality can hold its own for both deep sky and planetary use.

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One for Mulder and Scully

Last week I developed an observing plan intended to complete a tour of several deep sky objects in Lyra and Cygnus. At this time, both objects in Lyra (M56 & M57) have been treated. While for Cygnus, I have detailed observations recorded on the Eastern and Western Veil Nebulae and a potentially nebular region associated with an arc of stars near 41 Cygni. Objects as yet untreated include NGC 6888 (the Cresent Nebula -- near the center of the Northern Cross), and NGC 6826 (the Blinking Planetary near the west wing of the Swan), I had also hoped to revisit the site of the North American Nebula and identify the Gulf of Mexico region.

Since I had yet to unpack my scope from Sunday's elementary school session, I packed it into the car and returned to that scene around 5:30 PST. As the sky darkened, I made a quick check of seeing based on views of Epsilon Lyrae and Iota Cassiopeia. (Epsilon split cleanly, Iota was a little dirtier but still certainly a triple.) I also verified that a threshold magnitude marker star near Iota was, in fact, roughly of the 12th magnitude (possibly less) by comparing it's visibility with a known 12th magnitude marker come between Epsilon 1 and Epsilon 2. (The 12.5 come was hinted with eyes averted, while the 12.0 star was barely directly viewable.)

On the basis of the last few observations, I now find my self feeling that the unaided threshold limiting magnitude (UTLM) of the sky is around 4.5 when either of the 12.0 marker stars are just directly visible. I also feel that the sky is of fair stability when Epsilon can be cleanly double-split and fair to good when the Iota triple is cleanly separated.

Just after completing the above checks, high, patchy clouds rolled in. As the sky drew even darker, it was quite obvious to me that, but for the clouds, a night of superlative dark sky seeing was in the offing. (Possibly 5.5 UTLM.) Oh well. C'est la vie.

Pack it up. Take it home. Set it up in the backyard and wait. Occasionally during the course of the evening things did clear and I had a chance to recap observations of both the Eastern and Western Veil (Yup, right where I left 'um.) But I was unable to search for "first light" objects due to the variability in sky cover. So on to the planets...

Jupiter:

Since I had not gotten a clean split of Iota, and both planets were still relatively low in the sky (around 7:30, I had no expectations here. And such expectations were easily met. Cassini and Saturn SEB were just visible at 180X. Jupiter only displayed the two unsplit EBs. So while waiting for the planets to rise I came inside and surfed the web. (Visited the ALPO site and a few other links). Around 9:00, I resumed my observations. Still a masking cloud layer so I lost some brightness, but stability had improved with apparent altitude. The EBs were splitable on Jupiter plus a short central section of the NTB. I experimented with filters and decided that the blue filter displayed more detail than the green (influenced by low surface brightness conditions perhaps) and about the same as no filter whatsoever. Experimented with magnification (540 dismal, 360 acceptable, 210 fine -- but no "festoons"). Found myself wondering why I could never seem to get definitive detail within Jupiter's main belts. At one point I decided to remove the star diagonal and observe staright through the barlow (with everything stretched as much as possible to acheiev focus). But just as I configured the scope in this way, the clouds heaped up and dimmed the planet beyond recognition. (C'est la vie redux...)

Before my experiment removing the star diagonal, I noticed a satellite approaching the backside limb of the planet. In the midst of swicthing eyepieces, it scooted around back and disappeared from view. That's just the kind of tantalizing evening it was.

NOTE: While observing the planets, (around 8:15) I saw something traverse the sky I am unprepared to explain. Essentially, for roughly 2 seconds, a point of light moved from the south-southeast to the north-northwest at the speed of a meteor (covering perhaps 45 degrees of the sky), directly overhead. What was unusual about it was the rather erratic way it moved and the fact that it did not perceptibly change in luminosity. (It's motion rather defied the laws of trajectory as I understand them for any type of body either mundane or artificial.) The only possible explanation I can come up with is a tightly coherent beam of light reflected off thin clouds at a high altitude. There was no associated sound as the "object" moved across the sky.

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Shining Bow Star Arc Properly Placed

The sky started out quite transparent this evening (even from my backyard). ULTM was probably close to 5.0. Stability fair to poor (E2 is a dirty split.) I began my observations with an inspection tour of M57, M56, The Shining Bow Star Arc (near 41 Cygni) and the Eastern and Western Veils.

My scrutiny of the Shining Bow Star Arc this evening led me to believe that there is little, if any, nebulosity associated with it. The apparent "nebulosity" may actually be an artifact of the 6" telescopes inability to resolve a large number of dimmer stars. (The star arc is more likely an open cluster of an unusual shape.) One reason I believe this is based on experiments done using the OIII filter on the Veil components. Both Veils are rather difficult to "enform" visually (without the filter) and become recognizable as true nebulosity (showing definite shape and extension) only with the filter in place. The "Shining Bow Star Arc", however, is totally indifferent to the use of a filter. "Nebulosity" is suggested with or without it's installation. Regardless of nebulosity, I plan to continue referring to this asterism by the same name.

I then revisited the Western Veil. As I did so, I noticed that its northern component extends more than 1 degree from 52 Cygni. (This is at least 30 arc minutes greater than I first noticed.) This additional extension is not as perceptible as the 20 arc-minute segment described in an earlier report. (Although the "shawl-like" like shape is still perceptible.)

Had a few things to take care of, then resumed observations about 8:30. By this time the traditional "high thin clouds" started rolling in from over the Santa Cruz Mountains. Spent a half an hour attempting to locate NGC 6888 (the Crescent Nebula) located about 3 degrees southwest of Gamma Cygni (along the spine of the Northern Cross towards Nu). Due to the clouds - even with nebula filter use -- I was unable to get a positive ID. This particular quest will have to resume after the Thanksgiving visit with family...

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The Quest for the Crescent Begins

Devoted this evening to tracking down the illusive "Crescent Nebula" (NGC6888) near 34 Cygni. After an hour or so of continuous checks and counter-checks (using both the binoculars and the finderscope), I finally realized that I was always landing on the same "W" shaped group of stars. By carefully comparing an eyepiece impression from the book "The Deep Sky" (by Phillip S. Harrington) I was able to positively conclude that the Crescent Nebula (such as it was) location was found.

As far as I could determine, the surface brightness of this nebula is so low as to be virtually indistinguishable from the normal amount of "star haze" visible throughout Cygnus (and the Milky Way in general).

To find this "W" group of stars, begin by centering Gamma Cygni in the finderscope. Shift gamma to the northeast and look for three 7th magnitude stars forming a line perpendicular to the shift just made in the finderscope. If you think of Gamma Cygni as the top of a "cross", these three stars form the arms. The fifth magnitude star at the base of the cross is 34 Cygni. Two 6th magnitude stars are also visible between the arms and 34 Cygni. One lies on the spine of the cross. A second angles off from it and points the way to the "W" asterism. Center the finderscope on this line away from the cross by slightly more than the distance between the two 6th magnitude "angling stars" (toward the west from the cross described above). When you check the main scope (at 50X) you should see a squat, extended "W". Inspect the W for signs of nebulosity. If you can't figure out where in the "W" the "C" (Crescent) nebulosity is stationed, then it isn't visible to you under current sky conditions. (The nebulosity is supposed to be visible in a 4".) Under backyard viewing conditions -- 4.5 LTM -- I have yet to conclusively see any nebulosity.

Now that I can, in fact, identify the star group associated with this nebula I hope to get a view of it from a deep sky location and a better, more palpable sense of its shape, extent and surface brightness.

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Don't Blink You Might Miss It

After a quick check of Epsilon Lyrae (clean split / 12.0 magnitude come barely visible averted), I turned the scope on the "W" asterism associated with NGC 6888. Once again, no definitive declaration is possible concerning this "C-shaped" nebulosity. (It will take darker skies to reveal any nebulosity conclusively.)

However, I had much better luck finding the "Blinking Planetary" (NGC6826) located near the 5th magnitude star 16 Cygni. I started my search (as is my usual practice) using the 35mm (50X) ep. Due to the low LTM conditions (4.5 magnitude), 16 Cygni itself was not visible to the unaided eye. Under such conditions, I find that binoculars make it easier to identify a particular stellar configuration (based on star charts) then use the finderscope to hone in on the desired guide star. (Of course, binoculars give you the natural view of relationships between stellar components and you have to mentally flip everything around when you switch to finderscope view...)

In the case of 16 Cygni, the process is fairly straightforward. First find Deneb, then follow the northern cross to Delta Cygni. From there, locate the first 4th magnitude star about 6 degrees to the north. (That star -- Iota Cygni -- is part of the "Swans" wing.) Center Iota in the finderscope and look for a wide 5th magnitude optical double (Theta Cygni). Scan east one degree to 16 Cygni and center it in the finder. Then shift to the main scope view. There you should see a wide optical double of two 6th magnitude stars. Shift the two stars to the west by one half degree. You should then see what looks like a bluish, out of focus, star. To make out this "planet-sized" nebula, switch to the highest power ep conditions will allow.

At 200X (in a six inch scope), the "out of focus star" effect is transcended. The 10th magnitude star at the nebula's core begins to stand out on its own while a hint of dark sky is suggested around it. The nebula appears brighter just outside the darker core then blends off into space. (There is no clear sense of boundary as with M57 for instance.) I had no difficulty seeing both the nebulosity and the central star in the same direct view. Perhaps the most intriguing aspect of this planetary is its color. A pale soft blue gently announcing itself to the universe.

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The Quest Continues

Cygnus is now clearly below the central meridian after astronomical dusk. The new moon is waxing. It's unlikely that I'll get another dark sky opportunity to finish up observations planned for it (until the end of next summer when the Swan will once again glide above the eastern horizon).

Tonight I made another stab at viewing the Cresent Nebula. Just previous to making this "last gasp" effort to really "see" nebulosity, I spent some time reviewing the Eastern and Western Veil. I also made checks of Epsilon Lyrae. (Dirty split but both the 12.0 and 12.5 comes between E1 and E2 visible with averted vision at 180X.) Backyard seeing conditions were certainly better than the last few evenings, so I felt this was my last best chance for the Cygnus viewing season.

I found that I could definitely see the Eastern Veil (but not the Western) at 50X without the OIII filter. (Filter required to clearly make out the Western Veil.) This once again proved the value of an OIII filter on reflecting nebulae. Most definitely my run on the Cresent would incorporate the use of the filter...

In looking over my observing plans I noticed that I had also hoped to track down NGC6979 (located about 1.5 degrees west of the northern tip of the Eastern Veil Nebula). While viewing the Eastern Veil, I made several attempts to find it by slewing over to the expected location. But once again, I could find too much "apparent" nebulosity throughout this region to ever feel like I had found the nebula in question.

With preliminary checks made, I shifted over to locating NGC6888. I had little trouble quickly finding the "W" asterism. (It always amazes me how much more efficient we human beings are at doing something once we know what we are about.) As I turned my eye toward it, I noticed hints of thin line nebulosity between the northern and western stellar components. But the effect wasn't always reproduceable. "Star glow" continued to afflict the view. Certainly this large "aura" (not an airy disk) around stars is a bane to reflecting nebula detection. To offset it I ran the magnification up to 180X. Once again, I confirmed that higher magnification reveals dimmer stars and significantly darkens the background sky (as well as the star glow effect). But even this trick didn't reveal the nebulosity definitively. With or without a filter, there was no way to claim that anything other than the darkest seeing conditions can plainly reveal this nebula (in my 150mm).

NOTE: I have known for a while that I have an "optically incorrect" star diagonal on my scope. I have reason to believe that the diagonal is largely responsible for the abnormal amount of "skyglow" seen around stars. (See planets discussion below.)

Another Cygnis observing plan goal was to receive first light from NGC6940. I had better luck here. (Despite the fact that this compact open cluster was too dim on this occasion to be reliably identified in the finderscope.) After triangulating 2 degrees southeast of 41 and 3 degrees southwest of 52 Cygni then doing a little one degree FOV slew I picked up the view in the main telescope.

NGC6940 is rather strangely shaped for an open cluster. (Or shall I say, it is embedded in an asterism of a rather unusual shape.) The open cluster itself probably consists of 75-100 9-13th magnitude stars. However, surrounding it (in the shape of shark, dolphin or whale) are a number of brighter 7th and 8th magnitude stars within a one degree field. (The cluster is embedded in the belly of this sea creature. So a good name for it might be "The Jonah Cluster".) The whale asterism itself is oriented north-south. (The creature's head is to the north, and its dorsal fin points to the east.) Shooting straight up out of the cluster (to the south of the dorsal fin) is a column of dim stars. -- A rather unlikely location for a blow hole, but a plausible harpoon shaft!)

Using the OIII filter I briefly inspected the cluster for nebulosity. None was seen. (Until I solve the "star glow" problem I have my doubts about being able to make any confident declarations as to the presence of nebulae in the vacinity of stars...)

Planets:

To test my theory that the star diagonal is the root of my "star glow" problem, I pulled it out of the scope and made a quick check of Jupiter and Saturn using the barlow in the 2x configuration. Sure enough, I got the cleanest view of the planets and Jupiter's satellite disks that I have yet seen (with respect to limb curtailment). There also seemed to be an improvement in belt contrast and brightness in Jupiter's cloud belts. Unfortunately, before I had a chance to compare the view with the diagonal in place, high thin clouds moved in and that, was that.

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What a Difference the Seeing Makes

Arrived at the elementary school a little too late this evening to set up in time to use Epsilon Lyrae in determining seeing conditions. Fortunately, I had previously characterized Iota Cassiopeia and was able to determine that the seeing was unusually stable (based on a very clean split between the 5th magnitude primary and 7th magnitude 2.5 arc second companion). Unfortunately, as it usually goes, transparency was not particularly good. (Iota's 12th magnitude field star was visible using slightly averted vision.) Therefore, I would say that (initially) the unaided LTM was about 4.5. (Haze started moving in within an hour and things became impossible for deepsky observations -- even M42 was "unexciting" to view later in the evening.)

Before the haze kicked in, however, I did manage to review one planned deepsky object (M27: The Dumbbell Nebula in Vulpecula). Unlike previous occasions, finding M27 proved very simple. I had noticed in a star chart that the nebula formed a clean right triangle with Epsilon Cygni and Albireo. So I just pointed the scope at the desired point and used the nebula's relative brightness (magnitude 8.0) to pick out its dim, hazy glow in the finder.

First thing that struck me was how bright and large this nebula is. At 50X it took up about 10% of the 1 degree FOV. It had no trouble competing with neighboring field stars for my attention. To me it looked like a marshmellow "pinched at the waist". In examining surface brightness, I noticed that the nebulosity brightened to the southwest. In addition there were no edges to it. (It's frontier simply blends into the black of space.)

Framing the nebula are four 8th to 9th magnitude stars. Each star roughly takes up one of the four cardinal points (NEWS) arround the dumbbell. The brightest star oversees the eastern face of the nebula. This star lies near what I observed to be the most obviously "pinched in" portion of the dumbbell shape.

Viewing the nebula through an OIII filter is an experience. This thing must really be radiating in the hydrogen alpha and oxygen forbidden bands. Wow! I bumped the magnification to 120X but, to my eye, there was no particular value in doing so. 50X is fine.

About this time I started to notice a little more haze in the sky around me. I made a quick check of Cassiopiae and could barely make out Kappa (magnitude 4.2) -- the star that turns the "W" into a throne for the queen. So things were definitely spiraling down for deepsky...

NOTE: I also made an effort to locate the 6.5 mag globular cluster M15 in Aquarius (for first light). However, Aquarius was sinking toward the west and haze was becoming so thick that the ULTM magnitude headed towards 3. Because of this, there was no way to locate the globular in the finder (as I had earlier with M27).

Fortunately, when you have a 6" f12 Maksutov-Cassegrain telescope (MCT) there's always the planets!

Jupiter:

I started my Jupiter session by installing the barlow lens without the star diagonal. (Basically, this makes it a "straight-through refractor" viewing position.) The planet was about 60 degrees into ascendency and the viewing angle was excruciating -- but I wanted to see if there was any improvement in brightness or contrast when I eliminated the diagonal. In light of what I saw once I re-installed the star diagonal, I can make no claims in this regards. But the prospect of better contrast remains when you eliminate another optical surface from the light path...

Without the diagonal I could see that there was a lot of potential for pushing the detail limit this particular evening. But even one half-hour of on again/off again kneeling was enough for me.

With the diagonal in place, the viewing position was better but nothing like staying home, lounging on the couch, and listening to music...

What I saw:

As usual, both equatorial belts were easily split into northern and southern components. What was unusual, is that three of the four equatorial belt components (the exception was the northern NEB component) displayed irregular edges, and showed clear variations in surface texture. (I had never noticed this before.)

Textural variations (festoons) in the southernmost NEB component were also clearer than I had seen them in the past. (Typically, NEB details are visible in flashes, but tonight I could stare at them for minutes on end.)

The NTB was also clearly distinguishable. While an "echo" of the NTB was occasionally seen in the north polar region. (A part of the globe that often seems to begin at the NTB and darkens toward the polar limb without hinting at any kind of edge between NTB and polar region.)

In examining the southern component of the NEB, I noticed an especially large area of exceptionally dark detail progressed roughly 1/3rd the way across the disk. Other discernable detail was also possible to make out. (Typically, detail is suggested but not explicit.)

In all, I viewed Jupiter for over an hour, slack-jawed with appreciation.

By 10:00, Orion was well clear of the horizon. But before examining the Zeta Orionus double star, I briefly turned the scope on Saturn. At 360X, all the features I have come to admire were visible (Cassini, crepe ring, SEB etc.). (I didn't view at 540X, but I'm sure the Encke gap wiould have suggested itself if I had.)

Zeta Orionis:

Zeta is the southernmost of the three belt stars in Orion. Under tonight's superb sky stability, I was able to get an absolutely clean split between the 2.0 primary and 5.7 companion. The secondary's position angle was about 170 degrees. A 9th magnitude come was also apparent -- near position angle 0 degrees. The come was perhaps 45 arc seconds or so distant. The primary's color appeared bluish white while the secondary seemed to give off an "orangish" tint.

M42:

As mentioned earlier, haze rendered this magnificently bright nebula hardly any more interesting than M27 (viewed under better conditions early in the evening). In fact, it was not even possible to see the 7.9 magnitude "B" component of the Theta Orionis multiple (Trapezium).

All in all, this viewing session gave me the opportunity to fully characterize the Dumbbell Nebula. Views of Jupiter added another level of documented detail. The clean split of Zeta Orionis (under very good seeing conditions) provides me with a third double star to consult when attempting to evaluate seeing. The effect of atmospheric mist on deepsky objects was made quite clear to my perception.

End of November 2000 Reports

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