~T's Most Generous Gesture.
Short Focus Means Low Power.
Just How Deep Should This Baby Go?
Setting Things Up.
Daylight Testing.
First Planetary Light.
Not So Deep Sky.
Some Expectations Layed Bare.
Ease of Use Concerns.
Fast Newt Alignment and Collimation.
Through a Marginal Sky...
Through a Decent Sky...
Some Authoritative Optical Quality Validation.
Preliminary Conclusions.
Summer Season Comparo: Argo Vs Lightsop.

~T's Most Generous Gesture

Several weeks ago, while theAstronomer and I chatted online I let slip that although I was very pleased with 150mm Argo in most respects, the six incher was a wee bit shy of photon-collecting potential. On the spot, ~T graciously offered to send me out an Orion SVD-8 as a loaner.

Last week, as I went about the business of upgrading my eyepiece collection (and acquiring a few accessories), ~T's scope arrived. Meanwhile, that dreaded Luna was on the wax and I figured it would be little use putting the eight incher through its paces until the lunacy passed. So I spent the week evaluating a number of relatively inexpensive eyepieces sold by Orion while the Gas Giants spun overhead and Selene gained waistline.

With the arrival of Northern California's long anticipated February overcast, I dis-interred the SVD-8 from its wrappings and went about the new business of setting up the scope and preparing for deepsky use. Of course one concern you have about a scope that has just travelled two thousand miles by common courier is whether it survived the experience. Happily that was the case.

The next issue pre-occupying my thoughts had to do with mounting the scope on Argo's Skyview Deluxe. Would the tube rings properly mate? Would the additional counterweights strain the mount head? Neatly, everything came together.

Another question was whether the assembled scope and mount would fit through the study door. And again surprisingly, I was able to hand carry scope and mount out the door as a unit. The upshot here is that I will have no problem making a "grab and go" out of this 8 inch photon-gobbler. It should also be pretty straightforward to port the entire unit around Backyard Boulder Creek.

But there is a downside to all this. I'll have to come up with a "name" for the scope. Already there's "the Pup", "Argo", and "Vicki". Given the scopes aspect ratio (4:1 length to girth) "Fat Bob" came to mind. So did "Stubby". (~T calls the scope "the little pig". No thanks ~T, I'd prefer something more descriptive of what the scope is about and not so much what it looks like.)

Contrary to what some might think, "Argo's" name is based more on the idea of the "Ship of the Skies" - and not the fact that the scope was sold by Orion as the "Argonaut" model. "The Pup", of course, refers to Sirius faint and diminutive white dwarf companion. "Vicki" has less lofty allusions. The 102mm achromat was manufactured by the Vixen Optical Company of Japan. But what of the SVD-8? Sure it is short and squat. And both "Fat Bob" and "Stubby" capture this. But the scope is here because Argo is photon-challenged. And the name should reflect the role...

But no name springs to mind. Perhaps a few observing sessions will bring inspiration.

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Short Focus Means Low Power

First order of business: Giving my current eyepiece set, what magnifications are available through an 800mm focal length F4 newtonian? And how should I plan on using them?

To be clear such a scope is unlikely to be a "starsplitter". In fact, I would be very pleased if the 8 incher is able to resolve Summer's "Double Double". Alnitak's 4th magnitude companion will probably prove beyond the scope's optics. So to be frank, operating at anything beyond 1mm exit pupil is out of the question.

And to get 1 mm of exit pupil the scope will have to support 200x. And basically, at 800mm's I have nothing in my kit that is up to this. Even the 10mm will only achieve 80x. Add to this the 2x Shorty (1.8x actual), and now I'm at about 150x. Something I consider to be the minimum magnification needed to view Jupiter at. - But of course, it is very unlikely that this scope has the optics needed to rival Argo (or Vicki) on Jupiter. Frankly if the view is comparable to the 80mm Pup I'll be impressed!

TheAstronomer tells me the eyepiece of choice for this scope is the 12.3mm ED2. This should give 65x and slightly less than a one degree field (50 arcmins). However, the exit pupil at this magnification would be more than 3mm. - A pupil that conventionally results in reminding me of the astigmatism in my observing eye. One nice thing about using the ED2 is the large eye relief. Another is the fact that the magnification corresponds to the 3mm of exit pupil seen through Argo when using the 35mm Ultrascopic.

And what of the 35mm? Is 23x really usable in such a large aperture? Can you say two degree fields? But won't the sky brightening at such a low power be intolerable. Not to mention that no one's eyes (short of a owls) has an 8.6mm exit pupil!

All right then. How about the 25mm Ultrascopic? 32x. 1.6 degree field. 6mm exit pupil. Sure that will fit in a fully dilated eye. But then, from Backyard Boulder Creek this is three times the exit pupil needed to darken the background sky acceptably. Still, the 25mm is "in" for sweeper use.

So what's the usable kit? 25mm as "sweeper". But what about a "navigator"? 15mm gives 53x. This maps well against its 52 degree AFOV - one degree field. Its a natch. Add the barlow and you are almost at 2mms. The point where neither astigmatism or skyglow is much of a factor. Of course the barlow on the 12.3 gives 120x. Close enough to call a "framer" for galaxies, globular clusters etc. Detailer? 10mm with barlow will have to do.

So here's the kit:

In looking this over I suspect that the 15mm with and without the barlow will prove most popular for me with this scope. Dropping the 10mm into the barlow will be very useful for examining most Messier class studies and some of the brighter NGC's...

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Just How Deep Should This Baby Go?

So what about magnitudinal reach? Assuming I use the 25, 15 & 10mm eyepieces regularly, the following limiting telescopic magnitudes are most likely possible from Backyard Boulder Creek:

FL	X	Use	LTM
25	32	Sweeper	12.3
15	53	Navigator	12.4
15 barlow	96	Darkener	12.6
10 barlow	145	Detailer	12.8

To see if I am really gaining anything here, let's compare this to the Pup, Argo and Vicki at the same magnifications:

X	200mm Newt	150mm MCT	102mm Achro	80mm Achro
32	12.3	11.4	11.2	10.7
53	12.4	11.5	11.2	10.7
96	12.6	11.7	11.4	10.9
145	12.8	11.9	11.6	11.1

Almost a whole magnitude at each magnification. As I said, Argo is photon-starved. That's the thinking behind the big newt. Fewer reflecting surfaces. We will see if this is borne out by actual experience under the night sky.

Oh yes, by the way, I assumed 6/10 seeing and unaided stars to magnitude 5.2 when running the calculations. In fact the entire scheme was chosen in anticipation of the fact that the fast newt will never show airy disks discrete from diffraction rings. But to be fair, all the other scopes tend to get 7/10 seeing skies regularly. This adds .2 to .3 magnitudes onto their reach. And the gap closes. Still the eight inch gathers twice as much light as the six...

And where will that light really matter?

No, not on Moon, or planets surely. Double stars too will be out of the question. It all comes down to galaxies and allowing for half way decent optics - globular clusters. Already Argo does a sterling job on open clusters. You really can't beat those dozens upon dozens of pin pointy stars arrayed about the 70x field of view. And nebulae? Sure, some of the large fainter ones like the Rosette could be intriguing. But planetaries with their small angular sizes, high surface brightness and the demands they place on quality optics such as Argo's are already well covered.

No doubt the improvement will be seen in the galactic realm then. But I'm crossing my fingers that the optics are up to resolving globular clusters.

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Setting Things Up

Right out of the the box, one of the things I noticed about the newt is the "peculiar" observing position. For me, one of the beauties of an SCT, MCT, or refractor is the fact that you do the majority of your celestial viewing "seated". And of course, the seated position is enabled by a 90 degree diagonal - a device allowing for simplified eyepiece postioning as the scope is re-oriented during use.

With a newt, the "diagonal" is built into the scope. This "diagonal" however, is "fixed" in placed on the outside of the tube. To "rotate" this diagonal, one must turn the entire optical tube assembly in the tube rings. As it stands now, I am rather intrigued by the idea of adjusting the scope (and mount) in such a way as to minimze - if not entirely eliminate - tube rotation.

My first step was to stack the barlow and physically longest eyepiece (the ED2) into the focuser, orient the mount toward Polaris and point the scope toward the southern horizon. I followed this by loosening the tube assembly and rotating the entire tube until the focuser was parallel to the ground. Of course, this was also a nice opportunity to shift the entire assembly laterally in the rings until the scope was balanced fore to aft. Now while viewing studies within 10 or twenty degrees of the horizon I should be able to sit - not that such occasions are frequent from Backyard Boulder Creek...

I then re-oriented the scope skyward placing the extended eyepiece-barlow combination in the most unreachable position possible. (This is not overhead but toward the northeast or northwest.) In so doing, it was plainly revealed that the tripod legs were over-extended. So I had to go about the business of shortening them - severely! After several attempts I was finally able to get the eyepiece at just the height where leaning over the tube would allow comfortable eye centering.

Now all these efforts took place indoors. Rain and optical tube assemblies do not make for good associates... So I imagined myself outside under the night sky variously orienting the scope. One time toward Iota Cassiopeia to do a "seeing check" northwest. The towards the Great Nebula in Orion just south of the celestial equator. Or taking that first - no doubt dissappointing look - at a post-oppositional Jupiter hanging over the mountains to the east...

In so doing, noticed that somehow Orion's Taiwanese manufacturer had assembled the scope "left-handed". For instance, focus knobs were found on the far side of the focuser. And the finderscope was mounted such that right-eyed use would place the left temple against the optic tube. - Peculiar, but livable...

And what about that finderscope? 6x30mm! Why even at 150mm, Argo deserves its 7x35 achromat. A scope of eight inches really deserves 7x50 at minimum. Of course, I have such a finder - but now I am placed in a bit of a moral dilemma. That finder has been packed with Vicki for inclusion as part of the Astro Geekjoy fundraiser. (Skyview Deluxe mount, F9.8 Vixen 102mm achromat, 9x50 finder, and pair of decent plossls for 700 dollars shipped to the right astro-phile.)

But of course, once Vicki actually has found a home, I can always run down the road to pick up a replacement. Hmmmm...

So as it stands now I have done all I can do with the scope. Poor weather - and low-flying clouds makes even daylight testing an impossibility. (My favorite targets - a distant hillside meadow and cell phone tower are currently "veiled" by mists loitering at the ridge to the west.)

But that opportunity is sure to come - and things are ready...

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Daylight Testing

If Sunday, February 16, 2003 did not actually bring clear skies, it did, at least reveal the distant cell phone tower and high meadow used for daylight testing. So after morning coffee and bagel at Boulder Creek's very own "Blue Sun Cafe", setup the scope to take advantage of the partially clearing terrestrial viewing.

And learned a thing or two...

First, the scopes collimation was a wee bit off. In fact, after centering the cell tower in the field of the main tube, I ran out of travel with the finderscope. This in my estimation is a serious sign of mis-collimation.

Thankfully ~T had sent along Orion's version of a collimating eyepiece. This device fits into the focuser. At top it has a small aperture used to center the eye over the secondary. It also includes a crosshair illuminated by light entering an aluminum cavity. The idea of its use is to superimpose the collimator's crosshairs over the reflection seen off the secondary in the main mirror. Made no effort to adjust the secondary on this occasion - just the primary. Adjustment complete, had no trouble centering the cell tower in both main tube and finder.

Later as I cycled through all my eyepiece-barlow combinations, noticed a certain "twinning" and "offseting" of the defocused cell tower image as focus was traversed. Also noticed that precise focus was not achievable at anything above say 50x. So, followed the "rough collimation" done using the collimating eyepiece with "fine collimation". The method used was that used by most opticians when developing an optical formula for a set of spectacles. - The old "tell me which looks better" approach.

In performing this test, shifted each primary mirror adjustment individually first one way and then another. Made a note of which shift of the tower "improved the image. After each shift I'd recenter the tower in the field and try the next adjust. (Three in total.) There was a definite "handedness" to all three adjustments. On completion, used all three knobs to place the tower at the point in the field where it appeared best during previous shifts.

Then ran the focus traverse method to verify that "image twinning" no longer occured and that there was a certain "symmetry" to the way the afocal image expanded as it blurred in each direction of focus. A definite improvement was seen and I re-oriented the finderscope.

As I did the actual eyepiece series test, re-acquainted myself with a second phenomenon. As the Sun climbs and the earth warms, thermal refraction becomes obvious when viewing studies near the ground. This "heat wave" resolution effect is more definitely seen outside focus than in. Found that with a little precision focusing, I could effectively nullify higher frequency heat waves by going more inside focus than out. However, the net effect of such unperceived waves wa still to "blur" the image. What is avoided is the annoying, high frequency oscillations that easily distracted the eye when visible.

As mentioned, getting precise focus was difficult with this scope - even after correcting the alignment. Clearly its optics are less than "diffraction limited". (Orion makes no claim to this desideratum in its advertisement for fast newts.) But looking at the image, I'd say at best the scope is corrected to maybe 1/3rd wave and probably closer to 1/2. Based on this estimate (say .40 LSA) thought I'd give the scope the kind of Aberrator treatment done for Argo, the Pup, and Vicki.

So here goes:

Focused Star	Disparate Double	Extrafocal Startest	Planet Saturn	Planet Jupiter

Aberrator Simulation of Projected SVD8 Performance Under Perfect Seeing (-.40 LSA, .15 coma & astigmatism)

Aberrator Simulation of Argo's Performance Under Perfect Seeing (-.14 LSA, .003HSA)

Aberrator Simulation of Vixen C102HD Performance Under Perfect Seeing (1/4th wave SA undercorrected)

Aberrator Simulation of the Pup's Performance Under Perfect Seeing (-.17 LSA, .08 HSA .20 coma, .10 astigmatism)

In reviewing the above aberrator images the sense is that the SVD8's planetary and double star performance is considerably "overrated" by aberrator. It may be that even .15 wave coma and astigmatism is not achievable with such a fast scope. Meanwhile, there are other factors effecting starsplitting and lunar-planetary performance besides spherical aberration. Things like light scatter, optical surface roughness and zones come to mind. I'll know better once weather and sky conditions permit astronomical use of the scope. But based on the above simulations, the 8 incher should perform better than the Pup (I'd be surprised!), and possibly as well as Vicki...

But of course, today was about "daylight testing". In particular, on-axis clarity and and off-axis field flatness. The clarity issue has already been addressed. On this occasion things didn't seem to hang in there too well with magnification. I need better "seeing" to determine at what point additional magnification simply begins to degrade the image. But suspicions are that the scope will manage to support all the eyepieces (plus barlow) focal lengths currently available to me.

So with scope "rough collimated" (as described above), ran through the eyepiece series with an eye to the above parameters plus effect of central obstruction. In terms of this last parameter: "the central obstruction shadow", found that use of the SVD8 with 35mm eyepiece was unacceptable. Why? Because the CO shadow was obvious, well-defined and moved conspicuously throughout the field as the eye moved across the large eyelens. In fact severe field darkening appeared wherever it was allowed to dominate the eye.

With 35mm installed, went ahead and measured exit pupil. A whopping 8.5 plus mms! Certainly a huge factor when it comes to revealing the central obstruction!

At what magnification did the CO shadow become tolerable? This was seen with the 1.8x shorty barlow was installed between the 35mm Ultrascopic and the virtual image. Effectively some 20mm of focal length, 40x magnification and 4mms of exit pupil.

And at what point did it become negligible? Installing the 12.3mm ED2 rendered it still visible but innocuous. Therefore 3mm's of exit pupil and 65x seems to define the point where the shadow was diffuse enough for respectable daylight use of the scope.

All this says that the CO effect should be minimal under the night sky while using the 25mm Ultrascopic as a sweeper.

HOWEVER!

Field flatness testing on the cell towers nearby meadow revealed something of especial usefulness about the use of a shorty barlow. For you see, the scope's off-axis performance visibly improved by incorporating the barlow into the optical path. For instance, there was no example of an "unbarlowed" field showing anything approaching edge to edge flatness. The 12.3mm ED2 provided a relatively "flat field" only within the central third of the field - slightly more than than 15 arcmins in extent. Meanwhile, with 1.8x barlow installed, the "flat field" region took up some 80% of the total. Effectively, flatness increased to more than 20 arcmins through the same eyepiece. And only using the 10mm Ultrascopic and barlow combination did field flatness appraoch the "edge to edge" ideal.

All this suggests that best results with this scope require use of the shorty barlow to extend focal length. As such, eyepieces of choice now become the 35mm Ultrascopic plus barlow for navigation (40x, 5mm exit pupil, 72 arcmin field, with almost 50% flat field - 35 arcmins). 15mm Ultrascopic plus barlow as "darkener" (96x, 2mm exit pupil, 35 arcmin field, 75% flat field - 25 arcmins). And finally 10mm plus barlow as framer/quasi-detailer 1.4mm exit pupil, 21 arcmins of field flatness.

Now all that remains is to bring on them "clear and steady" skies...

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First Planetary Light

Clear no. Steady enough, yes. This very evening clouds over Boulder Creek thinned enough to get a sense of how well the SVD8 can perform on the Gas Giants. Saturn was up first and the view was surprisingly good - but for short stints. Like most scopes operating on the optical margins, more susceptible to changes in seeing than those of better alignment and more refined components. Add to this the additional photonic mischief seen with larger apertures and the almost impossible task of perfecting a fast newts collimation and you end up with what I saw. - A quivering planetary body oscillating into rare moments of almost Argo-like definition.

Cassini, occasionally ribbonlike and detectably encircling the planet's globe (but not above the south pole). Anterior ring shadow on planet. Planet shadow on posterior ring. Encke's minima, exceedingly well defined northern and southern frontiers of the SEB. Blue gray mottling in the south polar region. All very nice, unsteady early on and by 10:00 solid. This scope is a winner on the Ringed Wonder!

Later on, after gaining sufficient altitude, the Moon too -despite its fullness- gave a very promising view. Sharp contrasty limb demarcated by the profiles of easily discernable mountain ridges. Only the slightest amount of visible edge tremble. Two brightenings seen in Plato. Vast ray complexes radiating for hundreds and hundreds of miles from Kepler and Copernicus. And of course brilliant Aristarchus!

The real test of any scope of course is the ability to reveal low contrast features embedded in Jupiter's cloudtops. Would any dark barges be seen? Or perhaps even the more difficult white ovals? As I awaited Jupiter's ascent, took a chance on Orion through the thick atmospheric haze. Great Nebula unspectacular but whatever would pass for "skydark" had yet to arrive. As Jupiter ascended to the east, had a look at Rigel (whose companion was obvious.) Bright semi-disparate Alnitak though was problematic. Thought the fourth magnitude companion could be seen, but it lay in the typical star foo yung emitted by its comatic second magnitude primary...

Then at last Jupiter. And I must admit, it gave a better view than I had any right to expect. Certainly better than those seen through the 80mm Pup achromat. Around ten o'clock, caught two Galilean's passing within a few arcsecs of one another west of the planet's globe. Meanwhile, a third Galilean's shadow transited the NTB from the east. Occasional glimpses of the faint equatorial belt were seen. NTB edge irregularities also evident. Overall detail in Jupiter's cloudtops rivaled Vicki's - although like Argo, the brightness of the planet diminished contrast. But alas, the newt definitely has the collimation blues.

Early on I spent more than an hour tweaking both primary and secondary. The hope was to find that "sweet spot" where all signs of coma and astigmatism are banished. Progress was slow. Newts are different. Found that inside focus I could do a fair job on the primary by simply tweaking whatever knob drove the image in the direction of the coma. But secondary behaviour mystifies me and it will take more careful tweaking to arrive at an algorithm.

I'm hoping that, like MCT Argo, I can adjust the secondary extrafocally and primary intrafocally to balance the resulting images and nullify the astigmatism. But tonight I was just getting my feet wet with a newt. What I did learn was that I sure could make Jupiter look simply aweful by screwing with the knobs!

Focused Star	Disparate Double	Extrafocal Startest	Planet Saturn	Planet Jupiter

Aberrator Simulation of Projected SVD8 Performance Under Perfect Seeing (-.20 LSA, .40 coma & astigmatism)

Surprisingly, and aside from the unpleasant astigma-comatic issues, this particular SVD8 gave a remarkable startest. With Capella well overhead, traversed focus slowly and as carefully as possible. Kept the focus travel to the bare minimum. Watched as first in one direction and then the other a bright outer torus formed and bloomed as though near identical extrafocal images. Certainly the scope is undercorrected - but not by much. Watched the telltale starpoint go into abeyance just a few waves inside focus. Meanwhile, the same starpoint migrated extrafocally and expanded into a brightish inner ring. But that inner ring never got nearly as bright as the outer torus. For me this is the sign of "defraction-limited" optics. To be clear, and aside from the astigma-comaticism, the startest is superior to either of the achromats and almost rivals Argo's. Who'd a thought 1/5th wave spherical aberration - or better - from a 300 dollar optical tube assembly! But keep in mind most all such primaries are manufactured by automation these days. And quality assurance is the name of the game...

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Not So Deep Sky.

Contrary to the expectations of our local "weathermeisters", the last few nights have offered at least the possibility of trying out ~T's eight incher astronomically. As documented above, the evening of 16 February, dominated as it was by full moon and thickish clouds, demonstrated to my eye that the scope gives better than casually good views of Selene and Gas Giants. But the fast newt's optics, though fundamentally sound, will require a great deal of patience to properly collimate.

Last evening, the thickish clouds abated but Luna still dominated. Stability fell from the previous evening's 7/10 to something closer to 5/10. Ice crystal's in the upper atmosphere compounded the problem by intensifying Jupiter's native brilliance. The result was an overbright image that washed out everything but the two main belts. Saturn's Cassini Division lost its definition but still remained plainly visible.

I spent no time observing the Moon. The lack of feature contrast during the current phase offers little of interest to my eye and what little that can attract suffers all too much under marginal seeing...

As the sky darkened, turned the scope on Iota Cassiopeia - an especially arduous process given the scopes girth and the triple's northerly disposition...

Despite lingering astigmatism, found I could resolve the AB pair at 96x. AB as I recall, is separated by 2.5 arcsecs and as many degrees of magnitude. Certainly a disparate - but one easily resolved through the 80mm Pup achromat under similar conditions.

Of particular interest to me was the attempt to "hold direct" Iota's nominally 12.2 magnitude field star. Certainly every magnification from 40x up could show it with the least aversion. But it was only at 150x that it could be held direct under the conditions.

And what were those conditions? At best 4.5 ULM (near Iota). Assuming 6/10 seeing (at the time, later things degraded), the eight incher did precisely what it should have: i.e. held the 12.2 star direct at 150x through 4.5 ULM - 6-10 seeing conditions. Something that Argo needs 120x to accomplish through 5.3 skies of 7/10 stability.

But what really impressed me was the fact that the scope revealed an even fainter star in the region - one never previously suspected through 150mm Argo. (That star lay between the two 8th magnitude guide stars that point toward the "test" star.)

But from a "deep sky" perspective the Iota locale was the highlight of the evening. For in rounding up of a number of other studies - M31, 32, 110, 74, 76, 42, 43, 41 - none gave views that approached those of Argo under half magnitude deeper skies.

A fair test? Absolutely not - although it would have been nice to have definitively located M74 - even under the poor transparency conditions that prevailed at the time...

Of course, being the "optical perfectionist" I am, spent the bulk of the evening attempting to rid the scope of its astigma-comaticism. Found that with some effort I could eliminate the coma. This was possible using an algorithm deteremined the previous evening. "Drive the image intrafocally using the primary in the direction of the comets tail. And do the same extrafocally using the secondary."

But not the astigmatism.

This later appears to be an issue with the placement of the secondary along the length of the tube - towards and away from the primary. And it will take "daylight" collimation to work out the particular variables associated with this issue - followed by another evening of startesting to validate the method and fine tune the results.

NOTE: I later learned that astigmatism is not correctable by secondary position along the optical axis. What is correctable is a species of "vignetting" that behaves in some respects like astigmatism.

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Some Expectations Layed Bare

In writing up last evenings adventures, it strikes me that I should probably record some of the views I hope the eight incher will provide once sky conditions improve. Should for instance, it fall short of meeting these goals, it will not be that there is something inherently wrong with it as an instrument. No, it would simply prove that I am not an accurate enough prognosticator of performance! However, should the scope fail to meet these goals, then it also follows that there really is not enough improvement in deep sky performance to warrant going from six to eight inches of aperture either.

One hope is to get regular views of M31's main dust lane. Add to this little difficulty picking out star cloud NGC206 in the Great Galaxy's southeastern spiral arm. Nearby M110's frontier should be seen well defined. Faint satellite galaxy NGC147 should be as easy to locate as brighter 185 is now. Decent low power views of both M33's spiral extensions should be had. It would also be wonderful to definitively locate NGC891 from Backyard Boulder Creek. Dust lanes bisecting the M104 (the Sombrero) and NGC4565 should be obvious. Likewise that little curl associated with M65 in the Leo Trio. Finally, the spiral arms of M51 should be seen with the slightest aversion. - All this through Backyard Boulder Creek's nominal 5.3 ZULM, 6/10 stability skies...

On the planetary front, I'd like to hold the Little Dumbbell's frontier without aversion - ideally without use of nebula filter. During summer, I expect the interior of the Ring Nebula to "light up" a little. The expansive Helix Nebula in Aquarius should show definite structure. Planetary NGC2438 within M46 should be held without aversion.

Of the nebula, winter's Rosette should show a good deal of low power structure. Faint NGC2071 near M78 should be easily identified. M43, adjacent to the Great Nebula, should require no aversion to see its full expanse. The two main lobe's of summer's Trifid should give hint of a frontier - rather than simply blend into space as they typically do through Argo. The Eagle Nebula should also give a splendid view -especially through the Ultrablock filter.

As mentioned, Argo does a fine job with open clusters. I expect that the addition of stars within brighter clusters will go relatively unnoticed. However, there is a class of dense and distant open cluster that should "come alive" with another .8 magnitudes of reach. Several now spin overhead. Near M38 in Auriga lies faint NGC1907. And M35's distant line of sight neighbor NGC2158 should prove well resolved. Both these clusters reveal members through Argo. However, the eight incher should show the same stars without aversion.

Once collimation is "perfected", I hope to resolve Trap E regularly and have no trouble holding at least a dozen or more outlying globular cluster members in winter's M79 and summer's M56. Of course, the brighter globulars - spring's M3, summer's M92 - are expected to resolve as well through the eight incher as M13 does through 150mm Argo. The key to globular's is a certain combination of optical virtue and light gathering. Although Argo has the optics, the six incher simply lacks the ability to hold the many thirteenth magnitude stars that populate the finer globular clusters.

Add to all the above, the surprisingly good views of Moon and Gas Giants seen thusfar (plus what might be expected should collimation fall in) and I do believe this particular scope is a winner. Already I begin to suspect I'll have no small difficulty shipping the scope back to its rightful owner...

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Ease of Use Concerns

Despite the "glowing" comments already made about ~T's SVD8, I do have some grievances. Certainly difficulties collimating the scopes F4 optics head the list. However, I've also found that using the scope on a regular basis is somewhat problematic.

For one, the addition of a second counterwight to the SkyView Deluxe plus weight of scope itself pushes the limits of what I am personally willing to carry out of the study and shuttle between various Backyard Boulder Creek observing stations.

Add to this the fact that the large girth of the eight incher makes accessing right ascension and declination manual controls difficult.

Then of course, there are difficulties putting eye to finderscope in most sky orientations.

Finally, eyepiece position can be a bit unapproachable at times.

In fact, I have found myself on more than one occasion rotating the optical tube in the tube rings to finalize a good compromise eyepiece finderscope orientation. Ultimately, I may have to abandon any hope of optimizing tube position for use everywhere throughout the sky. In the end, I may have to plan observing sessions in such a way as to limit tube rotation from study to study or from night to night.

None of the above grievances apply to Argo. Certainly the SCT / MCT, fast refractor configuration - short tubes and behind the primary focuser position - is the most convenient possible for the visual observer. A position only made practiceable when using a suitable 90 degree diagonal. And one that allows for sit-down observation on a regular basis.

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Fast Newt Alignment and Collimation

Yesterday (February 18, 2003), pushed the limit of collimating the scope a tad. One step was to remove the the three (well-worn) phillips headed 5mm screws and replace them with slightly longer bolts. In so doing, I am now able to implement "tool-less" adjustment of secondary planarity. Certainly a great boon when making fine adjustments under the night sky.

The second step was to baseline the position of the primary by setting up a constant gap between mirror-back and alignment collar inside face.

Finally, removed the secondary, cleaned the diagonal mirror, and re-installed it with an eye to precision placement along the optical axis.

Employing the collimating eyepiece in the usual way, was able to get everything back into a semblance of "rough calibration" - as accomplished on earlier occasions.

Last night brought opportunity to check results. And after fine adjustment using the new "tool-less" method, was able to reduce astigmatism to the point where Capella collapsed into a single un-distorted virtual image. Oh sure, it could be very "flarey" at times of poor stability, but it looked like a bright star - as it can be seen through Argo.

But unfortunately, residual astigmatism means that achieving this view requires very adept use of the focuser.

So more work needs to be done.

Meanwhile the way is now clear. By day, make small adjustments to the position of the secondary along the optical axis. And by night?

Fiddle with the knobs!

Oh yes, and by way of validation: Under 6/10 stability, 4.5 ULM transparency, and at 120x using the ED2-barlow combination, Trap E required no aversion and Trap F hung right at the point of positive detection.

And the Great Nebula itself? Superb.

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Through a Marginal Sky...

Friday, February 21st, 2003 gave me several solid hours using "Lightsop" to tour a variety of "test studies". These I mentally compared to the remembrance of views past through 150mm Argo under a variety of seeing conditions. While making the tour, I hoped to definitively answer a number of questions for myself related to the "virtues" of aperture.

Given, for instance, the kind of skies I observe through regularly (especially from Backyard Boulder Creek) would another 2 inches of aperture and 90% percent more collecting area really make much of a difference?

And if so, on what kind of studies?

The answer on the Gas Giants only came with the culmination of Jupiter just before putting away the scope for the night.

For you see, even with limitation imposed by a significant degree of astigmatism, Lightsop revealed details in Jupiter's equatorial zone only rivaled by six inch Argo under the very best of seeing conditions - and with the MCT consummately collimated. For that wispy little equatorial belt bisecting Jupiter's equatorial region which just begins to reveal itself under 7/10 seeing, and starts to hint at variations in contrast and thickness at 8/10 through Argo, in fact displayed considerable structure through the eight incher.

But what about deepsky?

OK, not so fast. First back to the optics. I keep finding it very difficult to believe that a large fast newt can throw up such a startest. But for the still residual astigmatism, very comparable to 1/6th wavefront Argo. Bright outer tori both sides of focus. Excellent!

But I could be wrong. The test for spherical aberration is very sensitive to focus travel. So I try to keep that to a minimum and continue to get the same results: Bright, well matched outermost diffraction rings both sides of focus.

So OK, let's attack this from another angle... Tonight I devised a test so heinous I didn't believe Lightsop had a prayer of passing. It involved a certain very small planetary nebula - NGC 2022 - in Orion. No way this scope was going to pick a 15 arcsec size planetary out of a field of stars at a mere 40x. Right?

Wrong. And even better - the view of the planetary at 120x was excellent. Resolved both outer annulus and inner condensation. Very fine planetary for an eight inch. Add planetaries to the list of deepsky favorites this scope is capable of rendering...

So what's the hap? The optics on this particular scope are remarkable. But F4 is hell on collimation and it remains to be seen whether or not it can ever be perfected.

Now for more deepsky...

Not a great sky for the faint stuff. At best stars to 5.0 unaided could be held overhead. The usual Iota Cassiopeia check required 150x to cleanly distinguish the AB pair. So seeing outside the skies middle third just 5/10. Meawnhile, it also took 150x to hold the 12.2 field star. This calculates to 4.4 in San Jose's ever-sprawling lightdome to the north of Boulder Creek.

Later, ran a check against the 12.7 mag test star in Praesepe. 150x had a hard time holding without dissolve. So lets say 12.5 magnitude at 150x. Seeing maybe 6/10 in this region well within the skies middle third. 4.8 ULM calculated.

So figure the following observations were done through a nominal 4.5 sky. Tough seeing folks. And about as bad as I am willing to manhandle a scope for...

OK, at 7:10PDT, started out with M74 well outside the skies middle third and heading west. At 40x, no trouble turning up this low surface brightness galaxy. Vague sense of condensation against a gauzy-grey sky. Flared to all directions on eye movement - most especially south. At 96x, got the occasional sense of a starlike nucleus. Much flaring and no frontier. My best guess, this scope will certainly pick Messier's most difficult out of the sky early in the evening during a Messier Marathon.

Shifted to M31. First dark lane held direct. 2nd lane suspected. Like M74, M31 lay outside the skies middle third - so not bad. Not bad at all.

Quick check of M110. Well-condensed at 40x, but no sense of frontier. 96x brought out a highly elongated core region surrounded by nebulous mantle. No sense of frontier. No, not the optimal view here under these conditions either.

For the heck of it, headed north of M110 and took a west turn at Omicron Cass. Much to my surprise had no difficulty making out M110's fainter sibling - NGC147. In fact this large faint M31 satellite showed visible condensation even. Continued west to "suspect" the presence of even lower average surface brightness satellite galaxy NGC185.

But the fact is that neither of these galaxies are possible from Backyard Boulder Creek through 150mm Argo unless the sky is unusually transparent. And here the eight incher had to contend with 4.5 ULM skies. And Argo just shows 'em both through 5.5. Looks like that "plus .8 mags" for the eight inch is holding - irrespective of sky conditions.

Impressive. Very impressive.

Already mentioned that Lightsop did a prodigious number on planetary NGC2022. Any scope that can distinguish between stars and small planetaries through a 5/10 sky and under 4.5 ULM transparency gets my respect.

But what about M76? Could Lightsop do a good job revealing the "dumbbellity" of this faint Messier planetary?

At 40x, the usual "hazy rectangle" of luminosity - but easily picked out against the skyglow. At 96x, two lobes apparent joined at the hip - frontier flarey and ill-defined. The southwestern lobe obviously brighter however - along with a strong sense of central condensation. Use a bit of aversion and voila! Frontier.

Or if you choose, add an Ultrablock filter, and the dumbbell shape leaps out at you.

So, lets say a 5.5 ULM sky and this baby does a heavy lifting job on the "Little Dumbbell".

Time to head south to Lepus and drop in on Winter's main globular - M79.

Easily picked out at 40x. Even a sense of resolved components on eye movement. Up it to 96x, and a handful of brightest outliers - well away from the core - come out of hiding. 150x brings out a few more.

Very respectable. Should resolve decently under optimal seeing - lets say from Bonny Doon...

On to the nebulae:

M42 spectacular. Expansive and nicely structured. Plenty of tufts and folds at all magnifications. Unable to turn up Trap E this evening but seeing limited here. Need local 6/10 stability to get that definitive look.

The really important test was M43. Would I be able to "hold" the full extent of this largish star-embroiling nebulosity at 40x?

No. But it took but the slightest aversion. While examining the Trap region at 120x though, I swung over and there it was. Unmistakable and direct. That characteristics "nautilus" shape stepped right out under the spotlight and took a bow. I'm sure anything above 40x would have accomplished a similar view.

So being in the region had to swing by NGC1973-5-7. Expansive and obvious. Onto Alnitak for a look at the Flame. Would the burners be turned up? Sure, the eight incher had no trouble showing two lobes of NGC2024 even with 2nd magnitude Alnitak dominating the center of the field.

By this time Orion had entered the darkest region of Backyard Boulder Creek's southern sky. Say 5.0 ULM.

Headed up to M78. Easy. Great sense of extension to the southeast. This gave the nebulosity a "Caspar the Friendly Ghost" appearance. Something, I had never noted from Backyard Boulder Creek through 150mm Argo.

And what of M78's fainter twin - NGC2071? Clearly associated with the eastern 9th magnitude star - not the western. Gave that same sense of extension southeast that M78 does. Is there a "cosmic zepher" blowing in that region of space?

Well that wraps it for the evening's observations through Lightsop. The scope gets good marks for globulars, galaxies and nebulae - even planetaries under some very marginal conditions.

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Through a Decent Sky...

Clear skies continued into Saturday. So I dragged self, Argo, Lightsop, the Skyview Deluxe EQ, new accessory case and observing stool off to Bonny Doon for the one and only February 22nd, 2003 SCAC Star Party.

Managed to arrive not long after sunset. SCAC astrophotog mavin Dean preceded me. Chatted about things politic while waiting for access to the airfield. The owner stepped out of the hanger to open the gate just as SCAC club president Dwight turned up. Gate open, we drove to the edge of the airfield. Dean, to set up his G11 mounted 200mm Meade SCT. Me, to mount Argo on Skyview Deluxe.

By the time Argo was up and about, several other SCAC members joined us. Ralf and Troy brought along their LX200 250s. Jack, his Orion XT-10 dob. Andrew, an Intes-Micro 5 inch MCT on bogen tripod. Later El Marko arrived and elected not to setup his TV-85. Club VP Chris also made it. Certainly there were plenty of views to go around. We had a foreign visitor too - very intent on sampling each sight the various scopes threw up.

Saturn and Jupiter were spectacular - especially early in the evening - before upper atmospheric winds stirred things up. Dwight and Dean super-collimated Dean's 8 incher. Before and after views with Jupiter and Saturn were like Dr. Jeckyl and Mr. Hyde. Saturn: No problem at all tracing Cassini all the way around the planet (where actually visible). With Argo, takes a very steady "eye" to follow it completely. And it was an "Argo-like" view Dean got before collimation.

Jupiter's EZ showed only the vaguest hints of an EB before collimation. Afterwards? Fine variations in thickness and contrast across the EB's length. A view slightly superior to Lightsop's of the previous evening.

Dean's scope is now fully worthy of its G-11 ride!

As Dean did his astro-photo thing, made a tour of Messier (& friends) heading west. M74, was tough early on. Some core condensation seen later after skydark. M77 bright and sassy. Nearby NGC1077 detected but difficult. M31, 32, 110, NGC147 gave good views. NGC185 tough. M76, lowering M52, NGC7789, Double Cluster. - Especially that Double Cluster - just love that troupe of sharp 10th magnitude stars near the western cluster's core (NGC 869).

Orion entered that wonderful dark sky region due south of the airport. I started at Alnitak. Fine views of the Flame, NGC 1973-75-77, M43, and 42. Nebulosity simply exploded everywhere. Transparency 5.5+ ULM in that region - comparable to the zenith overhead. At 120x, Trap E held direct. Trap F came and went with aversion. Overall, under these fine conditions, six inch Argo - at best - just matched those thrown up by Lightsop under marginal conditions the previous evening.

Wasn't satisfied with Argo's views of the Gas Giants, so before mounting "Lightsop", tweaked the secondary collimation. This helped, but again not the view Dean had earlier through the 200mm. By this time, conditions had deteriorated, but frankly Argo would have been outmatched by the super-collimated 8 inch SCT anyway.

Mounted up 200mm SVD-8 Lightsop. Intriguing how so much aperture can settle on such a light equatorial mount. But working the manual controls is like trying to unbutton a matronly opera singer's bra - from the front!

El Marko, Dwight and I spent a good deal of time collimating the fast newt. Dwight explained that the scope's astigmatism could only be caused by some kind of mechanical stress on the primary or secondary. We eliminated the coma using Polaris but much astigmatism remained. Turning the scope on Jupiter was dissapointing - compared to views I'd seen the previous night from Backyard Boulder Creek. So I did what I always seem to do with this scope - tweaked the primary. Things cleaned up nicely. When it comes to low contrast detail, collimation rules - not aperture...

From this point on, mostly a "deepsky" occasion. The eight incher gave wonderful views of everything nebular. We turned the scope on M43 and confirmed that the "nautilus" shape seen at 120x from Backyard Boulder Creek could be held direct at 40x. El Marko, Dean and I, marveled at how we had ever failed to notice the peculiarities of the nebula's shape before. Of course, M42 is a hard act to follow and easily steals the show...

Also toured other scopes. Troy's 10 inch gave a decent view of edge-on NGC891 in Andromeda. Ralf tracked Jupiter at 300x through his 250mm. Andrew showed off a few doubles and several open clusters with the five inch. Nice stars. Good flat field.

Later, M81/82 looked spectacular through the two eight inchers. M51 showed spiral arms - a bit indistinct but manifestly there - San Jose light dome's efforts to the contrary.

Solid views of the Leo Trio. Saw far more extension to M65 than I'm accustomed to. However, that little "curl" associated with M66 not readily observable.

"Lightsop's" most memorable view was the innumerable thirteenth magnitude stars resolved across M3 - and the expansive spiral extensions of edge-on M98.

Things wrapped up 'round midnight. With scopes packed, and airport reactivated, headed out as a group. Another grueling night out doing "peace work" amongst the stars...

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Some Authoritative Optical Quality Validation.

While attending SCAC's February 23, 2003 star party at Bonny Doon, El Marko, club president Dwight, (an ATM of long-standing in the Bay Area), and I "ganged up" on Lightsop to give the ol' boy a going over. El Marko and Dwight brought their considerable expertise to bear in collimating the primary. But more significantly, Dwight (by chance) had also brought along several ronchi test gratings useful in examining Lightsop's optics for zones, and spherical aberration.

As I understand it (and on this occasion), a "ronchi test" may be done by orienting a scope toward a fixed "point source" of light. In this case, we meticulously centered Polaris in the 150x field. Removing the eyepiece, we placed the grating on the focuser lip and positioned the eye just above the grating. This was followed by adjusting the focuser until four or five of the visble grating lines came to focus. By inspecting the spacing of the lines for regularity. along with individual widths and definition, you can get an idea of how "well formed" parallel rays of light from the distant star are at focus. By shifting the grating around a little, I found I could cover the entire field of view. This, in essence, is what you might call an "in situ ronchi test" in a nut shell.

Of course the ability to use the above technology well wholly depends on the experience and sensitivity of the "inspector". And I personally lack any real expertise in this area. So it was amateur telescope maker (ATM) Dwight, that we relied on to make any "pronouncements" about the optic virtues of the various scopes - including Lightsop - that we tested. And the results please... Lightsop's primary is for all intents and purposes impeccable. At some 150 lines per inch - no visible zones, turned edge, or spherical aberration. Zilch. This 300 dollar fast newt, sourced by a company known more for value than optical virtue is a true "sport" for his kind. "Best of Breed".

Dwight also explained to me that no effort on my part to reposition the secondary will eliminate the astigmatism that hampers Lightsop's performance. For it is an established optical fact that astigmatism is caused by something mechanically stressing the primary or secondary mirror. And this stress will have to be removed for the scope to achieve it's full potential as an "APO-eater"...

Fair enough, but I don't get it. Why doesn't the Ronchi grating show the effect of the stress? Puzzling... And another question, why was I able to fix astigmatism shown by the 80mm Pup achromat by better planarizing the elements in the primary lens? Surely when you get two optical elements at odd angles to one another astigmatism can occur? Oh well, it is clear that I have much to learn when it comes to grasping the subtleties of "reflected and refracted" photonage...

Earlier, Dwight also ran the ronchi test on Argo. In fact this test was previous to Lightsop's. Amazingly, even I could make out the slight "bend" of the parallel lines around the central obstruction. Meanwhile, Dwight's finer eye detected some slight evidence of a "turned edge".

One question I had for Dwight was whether or not the central obstruction actually causes the slight bending seen around it. After all, photons swinging around the edge of the obstruction are literally "deflected" to a different point of focus than those away from the obstructions lip. Dwight opined that the obstruction would have no effect on the ronchi lines. I rermain baffled. Astigmatism messes with light. Defraction messes with light. Yet neither of these two are factors when it comes to a "Ronchi test". Stranger and strangerer...

But it's OK Argo, I still love ya. And its OK to be mystified by something that is both particle and wave at the same time too...

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In Conclusion

So OK, I've had to face some tough realities here. And several personal myths have imploded. Let's list 'em:

• Fast optics means bad optics: Not necessarily. It just means the manufacturer has to be more careful about shaping and assembling them steeper curves. And given the lower production costs of newtonian's (compared to all other archetectures) achieving these curves is more than feasible on an aperture for aperture basis.
• Fast optics means impossible to collimate: Perhaps not impossible - just more tedious, time consuming, and frequent. But after awhile it becomes second nature to tweak them knobs everytime you go out observing. But them knobs better be present and in good working order!
• Fast optics means unacceptably poor field flatness: Sure there is some fall-off, but certainly much better than anticipated! In fact, I am as pleased with the one degree fields shown by Lightsop as those of MCT Argo. Well, except for that drat astigmatism,
• Cheap optics means poor lunar-planetary performance: Probably, but there are exceptions. Individual variations in optical quality are more likely in an inexpensive line of scopes. You just need to be "choosey". (Or perhaps's lucky as in ~T's case.)
• Aperture is waisted under marginal skies: As documented above, a good eight incher will reveal through 4.5 ULM skies, what takes 5.0 plus to see through a six inch instrument.
• Two inches of aperture doesn't really matter: Right and wrong. It depends on your baseline. Even under optimal seeing, six inches of quality aperture is just not enough for a fine spread of globular clusters, galaxies, and nebulae. But going from an eight to a ten may not give the same incremental hint.

• Newtonian's are the "weak sister" of scope archetectures: In fact, due to smallish central obstruction's, the newtonian design probably has finer on-axis optical performance than comparably apertured catadioptics costing two to three times as much.

I also learned a few new things along the way:

• Newt's are hard to use: The virtue of a newt is it's low cost to aperture ratio. Even a three foot, F4 eight-incher is a bear to orient by hand, finderscope, or slow motion control. This is especially problematic when equatorially mounted. Such scopes need electronic drives on both axis, a line of sight unit finder, and two finderscopes flanking the focuser. Otherwise the tendency will be to simply take out the "grab and go" achromat or six inch MCT.
• Eight inches admits to a whole new level of deepsky revelation: There is a divide between six and eight inch performance. A new tier of galactic revelation becomes possible at 8 inches. But, I suspect it takes 10 inches to finally allow globular clusters to be resolved in all their glory.
• A fast eight incher is at the limits of portability on an equatorial mount: Yep. That's it for me. Much more and my back is done for...

But it wouldn't be long before I'd add a pair of electronic slow motion controls to the SkyView Deluxe. And somebody would be loaning me a ten incher for a scope review.

jeff's astrofeet are now perched precariously on the "slippery slope" of "aperture fervour".

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Summer Season Comparo: Argo Vs Lightsop

So OK, its the late summer observing season. A wide variety of fine studies visible overhead from Backyard Boulder Creek. Why not just set up 150mm MCT Argo and 200mm Fast Newt Lightsop and do something definitive???

Had both scopes positioned early under some late afternoon shade. Argo won "hands up" in the shlepping department. The 8 incher on EQ-3 mount takes some "mental prep work" before lift off...

By 8:15 PDST, Vega could be picked out of the early night sky overhead. Quick 150x defocus showed both scopes free of tube currents - so no issue here. Later in the season and with both scopes in "cool-down mode" Lightsop's open-air archetecture would no doubt achieve thermal equilibrium quicker than self-contained MCT Argo. Something to consider when comparing design types...

Made a quick check of collimation. The newt, about as good as it gets - given the astigmatism. Argo? Spot on. Needless to say Vega looked tighter in Argo than Lightsop. Lightsop also threw up those distracting diffraction spikes - all six of 'em.

Even through early evening skies, both scopes revealed that 10th magnitude come some 2 arcmins south of Vega. Little fellar sat there fat and happy in Lightsop - but required a wee bit of concentration through Argo. Argo's background sky appeared visibly darker than Lightsop's.

Neighboring Epsilon Lyrae was only an eye shift away in both finderscopes. So with the night still young, turned to the Double-Double. Both scopes resolved the pair at 150x. (F12 Argo loaded with 12.3mm ED-2 eyepiece, and F4 Lightsop pairing up the 10mm Ultrascopic and 1.8X shorty barlow.) Argo's view much more satisfying. First diffraction ring seen through Argo, while Lightsop showed "emanations" from Epsilon-1 primary tickling the secondary - not clean at all. Also visible "image twinning" afflicted both pairs through Lightsop. Seeing stability through Argo 7/10 while through Lightsop 6/10 at best.

Both scopes easily revealed the 10th magnitude come of the Epsilon multiple. While at 8:25PDST, Lightsop caught the 12th magnitude come near Epsilon-2.

Should give some idea how light the sky was at 8:30, when I tell you that I had to use the finderscope to locate 3.2 magnitude Albireo. (To be clear, I wasn't wearing glasses a fact that knocks about .5 magnitude from my unaided discernment of things stellar.) Through the main tube of both scopes, this gemlike beauty gave very satisfactory views. Lightsop the brighter, and Argo the cleaner. As for color: Argo's Albireo was golden yellow and azure blue, while Lightsop's, golden yellow and aqua.

At 8:35, time to swing over to the Ring. Maintaining 150x in both scopes, found the planetary's annularity better defined in Lightsop than Argo. Meanwhile, Lightsop could waiveringly hold a 12.8 magnitude field star while Argo required the slightest aversion with a 12.3. So maybe .7 magnitude delta between the two. Running the numbers in Astro.Geekjoy's Limiting Magnitude Calculator, assuming Argo looked through 7/10 stability skies, ZULM 5.1 at the time. Through Lightsop's 6/10 stability, calculated ZULM 5.0. Visually at this time wasn't quite able to catch all stars in the Lyre-parallelogram - so the unaided ZULM for uncorrected vision was closer to 4.0 than 5.0.

Really wanted to get a galaxy into the program - but the summer season holds very few noteworthy examples. Noticed the handle of the Big Dipper sinking northwest, dropped magnification down to roughly 55x. (Argo: 35mm Ultrascopic, 25mm Ultrascopic with 1.8x barlow). Turning Lightsop on Whirlpool and companion, able to make out both starlike nuclei direct plus the expansive - though unresolved - mantle of M51. Through Argo, NGC 5195's starlike nucleus, and M51's mantle required moderate aversion but M51's nucleus could be held direct. So basically it takes moderate aversion through Argo to get Lightsops view without aversion - no surprise here...

Time 9:00 PDST. Sunset 7:25. Skydark fast approaching. Maintaining low magnification, swung Lightsop over to M13 and was astounded by the profusion of 12 plus magnitude stars threwn up for my delectation! Meanwhile, Argo's view was comparatively dissappointing - full aversion needed to get anything similar... Bumping magnification to 150x, Argo gave a familiar view: Several dozen resolved members - some across the bright glow of the core. Star chaining evident. But it took concentration to see through Argo what Lightsop made easy and direct.

You know eight inches of Newtonian light grasp may be just enough to give globular satisfaction...

Well maybe not...

For you see as skydark fully descended. turned both scopes on 8th magnitude globular M56 in Lyra. Lightsop revealed about a dozen stars direct while Argo showed the same view with moderate aversion. Overall a modest view of numerous unresolved stars in a rich Milky Way field. Usable Globular buster really needs to do better on 8th magnitude clusters than those provided by 8" Lightsop...

Ah well...

Tracked down the Dumbbell Planetary (M27). Nice 55x views both scopes. Through Lightsop some extended luminosity and frontier definition. This only hinted at through Argo. Add a few stars embroiled in the planetary and Lightsop's view was completely satisfying. The view Argo gives from Bonny Dune - but conveniently offered up from Backyard Boulder Creek.

Left both scopes setup on the back deck. The wait was on for a culminating 25 arcsec Mars. 11:30PDST brought views through both scopes at 150x. Small but intense South Polar Cap, obvious Mare Erythraeum, and indistinct Sinus Sabaeus in Lightsop. But too much of image twinning and ill-defined focus through the fast Newt. Lightsop needs the stablest of skies to do the planets any justice.

Argo stepped up and delivered. Despite occasional image swim, edge focus quite achievable. Ran magnification all the way up to 325x without loosing detail. Toured from the south pole and walked the Red Planets central meridian: SPC extremely well defined within a contrasty Mare Australe. Argyre I tough, but Pyrrhae Reggio more straightforward. Mare Erythraeum, continental in proportion and separated from a somewhat diffuse Niliacus Lacus by a lackluster Chryse. No distinction between Niliacus Lacus and Mare Acidalium - so essentially Achillus Pons unresolvable.

Rotating in from Mar's west, Solis Lacus descried as a small projection from Mare Erythraeum. Meanwhile to the east, a phallic Sinus Sabaeus fully resolved north of a diffuse Noachis. Occasional spikey projections seen raying out from Mare Serpentis. Zen Lacus made occasional appearances as a faded and forshortened white eye rotating southeast.

On this occasion, had little patience with Lightsop's optics for planetary or close double star viewing. The fast newt, as shipped by Orion B&T (now no longer available), is in no way competitive with the similarly orphaned Orion Argonaut optically. To be sure, without the field flattening effect of the Shorty barlow, the scope would be unsatisfactory even for deep sky use by the optically correct. By adding the barlow however, the scope merits consideration as an aperture-optimized, (barely) portable backyard scope.

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