Saturn Still in Taurus
Saturn Occultation: September, 10, 2001
Saturn - On the Edge
Crepe and Minima
Cassini In Fullness Challenge!
Its Like a Fence....
Details on Saturns Disk
Blue-Gray Mottling

Saturn Still in Taurus

Hi All,

While Jupiter's eastward motion has carried it out of Taurus and into Gemini, Saturn seems to be hanging out and enjoying the company of the Celestial Bull.

Got up early this morn - not by design but by happenstance. Decided to see if recent improvements in doublet spacing and optical train collimation would yield any benefits on planetary work. Couple days ago had my best view of Selene yet - through the 80mm Pup. But a couple days before that had some gawdawefull astigma-coma-chromatic aberrational views as well.

Thankfully the changes wrought over the last week didn't disappoint. Pup gave a fine view of both gas giants. The view of Saturn was fair - not crisp. But I only viewed it in 80mm mode so not sure how the aesthetics would have been aperture stopped to 43mm.

Basically the view of Saturn was comparable to 150mm Argo under 5/10 seeing conditions. Cassini definite - but blurry. Nor could it be traced entirely around the system. SEB also obvious. Shadow of planet on posterior ring nicely visible. Good clean distinction between globe, space and ring.

The aesthetics were really quite good - but that's about all I got - good aesthetics. For the Pup to really arrive need a sharper view of Cassini and more of Ring A to be really satisfactory...

Of the four possible satellites, only Titan was visible - but then it was dawn. Even with the ailing Pup of last week saw four satellites while at Crater Lake.

Not sure what seeing conditions were. Didn't have a chance to check any stars before the Sun blanched the sky. But if conditions continued from last evening - probably 7/10. Not sure what time Saturn clears the middle third of the sky but by 6am it was just past culmination. So I suspect 2am is probably the earliest you will get a good look at it now. Meanwhile, Jupiter had yet to culminate so maybe 3:30 or so will give a good view of the other Gas Giant...

Carpe Noctem,

jeff

to: top of page

Saturn Occultation: September, 10, 2001

Just got the new S&T and saw that Saturn will get behind the moon at the 10th of september . One of the better places to observe this is the west Coast of the USA (Jeff). Around 12:00 UT the planet will disappear behind the moons limb. The next event is november 30th 2001.

Cor

Hi Cor

Thanks for the heads up, can't wait....

Actually, using the reverse psycology theory I really don't want to see either of these events and I have no interest in clear skies - I want clouds and lots of them....

That should work.

Alistair

You could buy a new telescope, the bigger the better since that will cause rain/wind/storm/mayhem !

Cor

Hi All,

So at 12:00 hours UT on Monday, September 10, 2001, Saturn is going to get swallowed up (and later spit out) by the Moon. And that particular event is going to be best viewed from the Western CONUS region where I happen to live. So let's see if its 12:00 in England (that's in the afternoon right?) then it's -7 hours PDST which means some 5:00AM in the morning!

Come on folks! Is it really WORTH coming off the astral plane for? (To sleep, perchance to dream. To dream of Saturn being eaten by the Moon - perchance)...

Or to see the real thing?

Hmmm...

That is the question.

~jeff

Ever tried a full eclipse of the sun ? I did and I would immediately wake up for another one. The advantage of sun-eclipses is that they have to happen during daylight

~Cor

Hi All,

Woke to the quiet insistence of the alarm clock at 3:45 am. Since I'd set the thing, there were no recriminations on my part...

Crawled out of bed (tempted to dawdle - but no I was doing this for me compadres!). Headed straight out the back door. Looked up to see a middling veil of overcast occasionally broken by night sky But, Luna could be seen. Clouds moved across her face, quite dramatic - for a Grade B movie!

Returned to don a full set of clothes. Night air chilly and I 'd be out for at least the next hour. Even wore socks and sneakers!

Had Argo setup in no time. Strategically placed to catch both Selene and Jupiter. Frankly, more excited about seeing His Royal Hugeness than a silly occultation! Made a quick finder check of Saturn's position before dropping in... Saturn sat well north of the Lunar equator and almost a moon's width from the western edge. - Plenty of time...

Jupiter had yet to enter the skies middle third. Slewed Argo over for a bit of a visit. Had the 25mm Ultrascopic in place with 3x configured barlow. Planet was huge - but ill-focused... Suspected this had more to do with my eyes than the seeing. Accommodation was poor. Made out two equatorial belts and that was it... Clouds made detail quite indistinct as well. During thinning, focusability improved considerably. Figured to come back after viewing Selene - bright Moon would probably be an improvement under the circumstances...

At 4:10am, not possible to fit both Saturn and Luna in the same 15 arc-minute field of view. Saturn, like Jupiter, was difficult of focus. Began scanning Selenes comely 3rd quarter form. Very rare for me to see the third quarter terminator. My impression was that the second quarter is superior Selene-north and inferior south. Historically paid little attention to Clavius, for instance, during waxation, but this morning found Clavius to be most intriguing. Of especial note is the "cochlea" of interior craters that sweep down from the south and west - each smaller than the previous. Also took a look at Plato - single brightening could just be held at center. Accommodation was improving. But clouds still piled up across the surface, and contrast went to hell. Moon turned into a huge "goop melange" of garbled structure...

By 4:21 clouds thinned up a little. Could hold both planet and lunar limb in the same field. South Equatorial Belt (SEB) and Cassini's Division, though less than "well etched", could be seen more or less consistently. Stability was probably 6/10. Decent enough - transparency remained quite variable.

Next stop was to guesstimate where on the Moon's limb Saturn would occult. Followed a line of craters - Anaxagoras, Philolaus, Carpenter and Pythagoras. All on the far side of Mare Frigoris from Plato. Westernmost Pythagoras would probably be south of the actual landing spot - but at least I had a reference. Interestingly when I first noted the relative positions of Saturn and the Moon almost looked like they would miss entirely! It was only after observing for a while that it became clear the major axis of the ring system pretty much pointed to where the planet would "touch the Moon"...

Around 4:30, clouds really began thickening up. From my notes: "Amazingly swift progress of the Moon towards Saturn". This stimulated me to think about just how fast the Moon moves against the starry highway of the ecliptic. Figuring 360 degrees in 28 days (roughly) means progress of more than 12 degrees per day. At that rate it gobbles up its own apparent diameter per hour!

By 4:36, some clearing. Noticed Titan preceding Saturn west and south. Clearly, Saturn's main satellite would be hidden by Earth's only Satellite first.

At 4:40, Titan lay roughly equidistant between Luna's limb and Saturn. Moonglow off variable clouds obscured it frequently. Never did see it "touch down".

At 4:52, notes say that "the Moon trembled with anticipation" at engulfing Saturn. Made a mental effort to see the planet as far more distant from the Earth and larger than the Moon. This was a fairly easy mental gymnastic and I had no trouble staying in touch with the notion of relativity this implies.

At 4:54 (alarm clock time) Saturn's western Ring A made contact with the Lunar limb. In another minute, the planets western limb makes contact and the ring ansae is gone. Another minute later and Saturn's disk and the eastern ring ansae also disappear. Locale of occultation was adjacent to a small, hugely elliptical, dark basin between craters Harding and Naumann west of Sinus Roris.

Spent the next fifteen minutes getting the occasional impressive view of Jupiter. After all the straining after Martian detail of the last few months, Jupiter seemed a wonderland of visual delights.

5:15am: Put Argo away. Felt no special call to try and catch Saturn's probably far more dramatic re-emergence from the dark side of the Moon...

~jeff

to: top of page

Saturn - On the Edge

Hi Folks,

The Gas Giants have turned the corner. Early risers like Otto and theAstronomer are now posting emails regarding their observations of these two stunning worlds.

Most amateurs list three very difficult aspects of Saturn that make for very challenging views. Each is a ring phenomenon and two are within reach of high quality optics beginning at about 150mm. The first is the innermost ring of the planet: The Crepe or "Dusky" Ring. This is an extremely dim enhancement of dark space within Ring B that is generally only visible in front of the planets body (as a dimming) and sometimes east or west of the planets limb (as a vaguely "brightening"). One difficulty with this ring is that Ring B naturally shades inward at the margin. There is no clear line of demarcation between middle Ring B and the inner Dusky Ring. So if you are like me, it's easy to believe you've seen the dusky ring when you see the dimmest parts of Ring B. (And in fact you may very well have seen it!)

The second "Saturn on the Edge" is the Encke Minima. The Minima is not an actual "division" like Cassini's. It is a contrast phenomenon about half-way out from Cassini's to Ring A's frontier. There is a vague "dimming" of Ring A in this location. I have seen this with 150mm Argo unequivocally at 540x under 8/10 seeing - so it is much easier to see unambiguously than the Crepe Ring.

Finally Ring B itself has its own feature - besides Cassini. Observers using larger, optically correct apertures, report seeing "spokes" or radial variations in surface brightness emanating outward from the core of the ring structure. It is very unlikely that those of us with 150mm scopes will see this phenomenon. However, it makes sense to begin looking for any kind of variations in surface brightness in Ring B.

Carpe Noctem,

jeff

Hi

Seeing features like the minor rings-minima on saturn is depending also on the size of the planet. . During the end of november/beginning of december the planet will be two arcseconds bigger than currently. The Major axis will be 46.5" and the Minor axis 20.3" in diameter at that moment.

greetings

Cor

Hi All,

Last Saturday night attended a star party at the Santa Cruz Astronomy Club's Bonny Dune observing site. By 2am the sky had gotten superbly stable and transparent. Saturn had yet to reach the skies middle third but was giving simply audacious views through 150mm Argo at 120 and later 180X. The ring system is incredibly well presented. Certainly the tilt is such that the minor axis extends as far as the planets own 18 arc-second disk.

Saturn's globe was tack sharp. The southwestern edge was rimmed with sumptious shadowing. The South Equatorial Belt (SEB) pronounced - though lacking in fine detail. What I consider to be the most engaging aspect of the planet's body itself was supremely evident: Beginning slightly south of the SEB there is a blue gray mottling that extends alll the way to the south pole. The mottling is intricate in pattern and beyond all description. It is simply a texture - like a finely knit rug or carpet. The blue gray coloration most subtle and engaging.

As mentioned, the ring system itself was gloriously aspected. Cassini was sharp - but only occasionally razorlike. Outside Cassini (in Ring A) I was astonished to see the Encke Minima. (But only under the moments of finest seeing.) Why was I astonished? Because I was only viewing the planet at 180x!

Turned my attention to the transition region inside Ring B. Got a very substantial sense of a "milk-chocolate" region inside Ring B's frontier. Thus, to my eye, the Crepe Ring (Ring C) was also susceptible. Because I was also doing a great deal of "Deep Sky" at the time, elected not to install the barlow and run up the magnification.

Besides, there will be plenty of time to dote on Saturn as the season progresses...

Clear and Steady,

jeff

to: top of page

Crepe and Minima

OK guys and gals,

I don't get it. I look at photos taken with a 150 mm deluxe mak cass and I can see the crepe and clearly see the minima. I look at it on very fine nights with my own eyes and I don't see either. Then I look at the 14 inch photo Jeff has on the "On Edge" thread and I can clearly see the crepe and not see the minima. And finally, there are the NASA voyager photos which show crepe and encke division and striations....but no minima. So what gives? Are my eyes bad? Are there two Saturns? Is this magic?

- Otto

Hi Otto,

The minima is a feature on Saturn that is less obvious in nasa-pictures probably because of its nature. I have not seen this myself too but from what I read it seems to be a low-contrast zone that appears like a darkening band. Read more about it and its discovery on this page:

http://users.metro2000.net/ericj/encke.html

Cor

10/28 3:30 to 6:30 EST, clear, still, deep (zulm 5), low humidity, cold (below freezing), very steady. Saturn was crisp up to 450 X (3X per mm) and showed no significant degredation of image up to 900X (6X per mm; 150X per inch), with the cassini still nicely visible. I am seeing something where the crepe should be, but only on one side (anse). There is a definite graying on the inside of the bright ring on one side only. I don't understand this. This observation is consistent night after night. Perhaps a hint of the minima, but I still think the minima is some type of linear diffraction optical illusion. The seeing was so good that the cassini was not a black thin pencil line, but actually a very black ribbon. One other interesting feature, on the ball of the planet, nestled up to the ring passing in front of the planet and occulting the bottom of the planet, is a band of whitishness-about the width of the ring occulting the planet.

- Otto

Hio Otto,

Just got in and decided to write up a few notes before settling in with Jupiter for a while. (It's now midnight and the sky down low -though pretty decent - can be improved on).

There is no question about the ability to physically see a faint, dark, "line" at BOTH the eastern and western ansae of Ring A. In fact I can tell you that this particular feature lies about 2/3rds the way out from Cassini toward the Ring A frontier. There is a feature there - though, as Cor says, higher resolution photographs fail to reveal it! (Forest for trees effect.)

As for the Crepe Ring. That too was evident this (as on other) evenings. There are two methods to locate it:

1. Start with Cassini near the Ring A ansae and move inward with the eye along the plane of Ring B, You then see the bright yellow of Ring B begin to fade toward a duskier golden brown. When the brown becomes "chocolate brown" you've found the Crepe Ring. It is most certainly "slightly different in luminosity" from the dark of space between Ring B and the body of the planet.

2. Again start with Cassini - but this time due north of the planet's central meridian. Shift the eye south until you see a thin translucent region where you might expect the NEB to be found. (I believe this "veil-like" band in front of the planet is in fact the Crepe Ring filtering some of the northern EZ's light.) Now begin at this veil and move the eye laterally - see if you can pick out the "chocolate brown" described above. Personally I consider the Crepe more of a challenge than the Minima (because of its subtlety). Happy to be able to report that tonight under 7+/10 stability (and high humidity!) was able to see both using 210x on up. I am confident that once you catch sight of these features you will be able to see them with frequency.

Clear and Steady,

jeff

to: top of page

Cassini In Fullness Challenge!

Let there be no doubt, Saturn is in wonderful presentation this apparition. In fact, this very evening I noticed that posterior Ring A actually exceeds the SPR limb by a significant degree. One so significant that I offer up this challenge: Can anyone definitive tell (at the eyepiece) whether Cassini can be seen "all the way around" the ring system? Surely it can be seen all the way along the anterior edge. But can it be seen above the southernmost pole of the planet?

Ah Carumba - even through 150mm Argo at 540X and 7+/10 seeing I could not definitively determine if it does or does not! This one is very close and will take the very best equipment and night of seeing to get a satisfactory answer - especially with the shadowplay seen at the pole!

Have at it then! And may your contemplations of the Ringed Wonder be gratifying as well as enlightening.

Carpe Noctem,

jeff

Hi Jeff,

I just had a short peek at Saturn (about 20-30 minutes) before a halo around the moon started to spoil the whole sky. I am confident that the division is visible as a broken ring, in my view it dissappears behind the Southpole slightly below the top of the globe. I can see it running against the planet at both sides. I had more trouble seen the ring as a complete ring in the part that passes in front of the globe. But this evening things where easy enough. Crepe again visible and at times I saw that darkening we call encke minima but .... it just feels like a optical illusion. I can definitely see a darker arc that is diffuse in appearance and not as wide as cassini about halfway the A-ring or so. I need more time to study this.

Cor

Hi All,

At this last SCAC Star Party (12/15/01), had a chance to examine Cassini very closely (540x). At the planet's current ring plane presentation it can be seen all the way around the ring system but IS occulted by the very tip of the south polar cap (as Cor had previously noted visually and as displayed in Andrea's photo).

SCAC club president Dwight believes that the modulation in apparent brightness seen on the inside of Ring B is in fact evidence of "unresolved spokes" of gravitational interference radiating outward from the planets gravitational well. Those unresolved spokes were also very obvious at the star party and showed a rich diversity in apparent brightness.

I was also able to resolve Cor's "Frosty the Snow" anti-division on the far side of Cassini in Ring A. Dusky and Encke were obvious at all magnifications used. 9/10 seeing combined with high quality six inches of aperture simply has to be optimal for studying the planets ring system. However, the planets disk itself is less than satisfying and requires more inches. I'd say a 12 inch under the finest seeing MIGHT just show enough to make it ALMOST as engaging as Jupiter through an 80mm scope.

One thing to look for in the future is whether the planets north polar region can be seen through Cassini anterior to the planet. Just didn't think to dwell on this question on this last opportunity... (But its always nice to have something fresh to look forward to!)

So if anybody ever asks you "Why Saturn?" the answer is simple - "It's the Rings, Man, the Rings."

jeff

to: top of page

Its Like a Fence....

Ah guys and gals...it was a postcard night. Absolutely spectacular. Saturn revealed new detail up to and including 360X, and held magnification very well up to 720X and even at 900X (a silly 150X per inch). Though, I doubt I will ever see the crepe at the ansae and the minima directly as say one sees the cassini division...this evening I had the very definite impression of clear glimpses of the crepe and the minima. The crepe is a dirty brownish gray aura within the main ring all around. But, and you all can crunch the numbers on this one...I believe I saw the disk of the planet bleeding through the cassini division at one tiny swatch of area at the bottom of the planet.

Looking for the disk showing through the cassini reminds me a great deal of your study of magnifications through the MK67 by using a distant fence line Jeff.

- Otto

Kudos on a fine night Otto. I think its great that you got to be the first one to start "peeking through Cassini" like that. Makes sense to me that you should be able to see the planet through it - especially when it takes on that "razor sharp" appearance during spectacular seeing.

- jeff

Hi Otto,

Glad to hear things went "fine" this evening. Seeing the globe through Cassini is only possible at moments of good seeing. How much "light" did you have left after pumping up the photon-magnifier to 150x/inch ?

regards

Cor

That is an interesting question you ask, Cor; "how much light was left after pumping the magnification up to 150X per inch." To be honest, I didn't notice any difference. Although I am sure there is a difference. I think this is an example of the mind filling in what the eye doesn't see. What convinced me that magnification does in fact make things dimmer was when a non scopist friend looked through a scope at two magnifications, c. 20X per inch and c. 60X per inch and commented on the great difference in brightness.

I can't honestly say I see that frosty edge. Maybe my eye does good on contrast but not on colors. Jupiter looks like a set of pastel whites or various grades of plaster of paris.

- Otto

Greetings To All,

Yes...I am BACK..had Nice Clear Skies last night

What a Joy to get back into the Yard and look up an around.

Saturn:

One of My Favorite Planets was clearly on Show last night , Stunning as usual. Pointing the ETX due west , She Rose in Formidable Fashion and Shining Brightly with Aldebaran Virtually Underneath. Maybe it is me , but Aldebaran looks Positively Brighter than Saturn.

Anyways....Racking up to 210X (9mm) , Saturn Looked Splendid rising from the East , was able to make out the Cassini Division No Problem..Once again I thought i had a Fleeting Glimpse of Titan....kind of a Shadowy Blob.

Was Just please to get out and look at My Fav Planet and at least welcome some Clear-Skies.

Clear-Skies to All

Bill

Yo Bill,

Way to go! Now that you are seeing Cassini regularly check out the SEB on the planet itself. Curiously, sometimes you can see it as a "distinct" belt and sometimes only the northern frontier. Check it out next.

Clear Skies, Ft Worth,

jeff

to: top of page

Details on Saturns Disk

Hi All,

A consensus has emerged among the Makscopers amongst us that the major components of the Saturnine Ring System (A, B, C, Cassini Division, and Encke Minima) are truly visible through "optically correct" 150mm scopes. (Certainly better nights of seeing and moderate to high magnifications are required.)

As we continue to scrutinize the Ring System for other mysteries (spokes and shadings) we may also want to spend a bit of time attempting to resolve features on the planetary disk proper. In so doing, one goal might be to carefully follow the SEB and look for signs of edge delineation and shadings. Another is to look for discrete brightenings and darkenings within the temperate region.

You never know about such efforts. Who'd a thought last year (when many of us resumed serious observing) that seeing the Encke Minima would become a commonplace!

As T says, "practice, persistence, patience"

Carpe Saturnum,

jeff

to: top of page

Blue-Gray Mottling

Hi All,

Sure, Saturn's Ring system is the toast of the solar system - but there are other treasures to be found on Chronos proper. The most obvious feature on the planets disk is the currently presented South Equatorial Belt (SEB). Careful contemplation of the SEB can sometimes yield variations in color and contrast of most subtle and engaging virtue. But as the eye travels south of the SEB, the planets South Polar Region (SPR) is seen. Proximate to that polar region and possibly including it is a fine blue gray mottling or texture. This "texturing" of the planets surface is simply indescribable - or so I think.

But does the word "indescribable" really capture the essence of this region? Can't we do better than this? Surely those of us who choose to observe this planet regularly can begin to "detail out" what we are seeing.

Thus this thread. As the planet moves once again toward evening skies, let's see if we can't take the "in" out of "indescribable" of this particular aspect of the planets globe.

Let's also see if we can't get a better sense of the conditions and equipment needed to show this phenomenon well.

Of course, to accomplish this we will somehow have to manage to pull our attention away from the planet's ring system.

That's the real challenge...

Carpe Noctem,

jeff

Greetings All,

To my great pleasure and astonishment the 80mm Pup revealed the beautiful blue grey mottling texture in the NPR this evening. (Formerly a 150mm Argo perogative only.)

Sky was inordinately still and despite the fact that the planet lay less then 20 degrees above the horizon the view was a sharp a one as I've ever seen through the Pup. Fine edge focus. Pencil thin Cassini. Planet and ring shadows. And now the "Blue Gray Mottling" in the south temperate and polar regions...

Another first, the view through the Pup at 80mm was the equal of the view at 67mm - possibly finer... Made a number of focus traversals - perfect proportionality both sides of focus at 120 - 240x.

Best view of the planet this night seen at 200x. 15mm Ultrascopic, plus 3x and 2x configured barlow lenses.

Thats a lot of glass for 80mm diameter and 400mm focal length.

Clear and Steady,

jeff

to: top of page

to: AstroSpeak Index Page

to: Astro.Geekjoy Home Page

Email: Astro.Geekjoy