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Saturn 3.22.09

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#1 Sol Robbins

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Posted 21 March 2009 - 02:56 PM

Hi,

I'm so glad this forum exists. Since I haven't had good weather for a really long time, I can observe through the eyes of everyone that posts here.

Anyway, I finally had the opportunity to get out last night with my 6" refractor to observe Saturn under reasonably good conditions.

Seems like the SEBs has gotten lighter than I last remember.

I believe that the dark ring feature crossing the globe is actually the Crepe Ring. Recent sketches I've seen show this dark line as being north of the northern edge of the rings crossing the globe. To me it seems to actually be south. Its also only slightly darker the SEBn. A ring shadow usually appears darker than this to my eyes.

Some darker segments appeared on the borders of the NEB, but nothing as intense as my last observations under better sky conditions.

Other equipment details are embedded in the sketch.

Sketch was executed using a 4H pencil. I used my fingers for blending.

Best,

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#2 Sol Robbins

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Posted 21 March 2009 - 03:30 PM

Here is the template I made for the sketch above showing the most recent ring tilt.

Feel free to print it out for your own use.

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#3 CarlosEH

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Posted 21 March 2009 - 03:51 PM

Sol,

An outstanding observation of Saturn showing much detail. The South Polar Region (SPR) appears thin and mottled with thinner bands to the north. The South Equatorial Belt (SEB) appear bisected with the northern component (SEB-N) thicker than the southern (SEB-S). The Equatorial Zone (EZ) appears bright. The North Equatorial Belt (NEB) appears broad containing thin white (bright) rifts. The North Polar Region (NPR) appears dark to shaded and mottled. Thank you for sharing it with us all.

Carlos

#4 Sol Robbins

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Posted 21 March 2009 - 04:24 PM

Carlos,

Thanks very much.

#5 mike bacanin

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Posted 21 March 2009 - 05:07 PM

Sol,
a beautifully drawn and interesting observation of saturn, i really enjoyed seeing it!

Regards
Mike

#6 frank5817

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Posted 21 March 2009 - 07:20 PM

Sol,

Always a pleasure to see your sketches here. The details are exquisite. :bow: I never thought about what you mentioned above; the ring shadow in late February was clearly on the north side of the rings. So a shadow like gray on the south margin must be the C-ring.

Frank :)

#7 Sol Robbins

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Posted 21 March 2009 - 07:47 PM

Mike & Frank,

Thanks.

Its hard to see if the C Ring and/or ring shadow in front of the globe lies north or south of the foreground until high magnifications were used. That said, still not very easy to ascertain.

Thanks again,

#8 varmint

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Posted 21 March 2009 - 08:12 PM

Sol,

Your sketches, as always, are amazing.

Is it just from years of experience, seeing, or what magic are you doing to see that much structure and detail in the planets? :grin:

I've spent an entire evening doing nothing but staring at Jupiter to try and pull out more detail than just the usual 2-3 belts, and only once have I been able to see what I thought was a single festoon.

I've always felt the seeing has been the limiting issue for me. I don't often get above 4/9 here.

Do you have an example of a sketch from a poor seeing condition?

Thanks again Sol, and for the template too.

#9 Sol Robbins

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Posted 21 March 2009 - 08:45 PM

Jim,

Doing this for a lot years does go a long way. My first sketches were not anything like what I am able to do now. Being able to pick up on details comes with time. There are also what I would call telltale signs that would lead you to see festoons at least initially. You eventually learn to see what festoon you think you see actually looks like.

I also have evolved the way I draw that is somewhat friendly to my scanner so the details I draw actually reproduce in this format. This makes for a more heavy handed approach. If I sketched in a way, which I do at times, that was more true to the contrast range of what I actually see the details would be more subtle. Jupiter and Mars are better for this and still remain scannable. Saturn sketches are much more of a problem. For example, the 2 rift features, 1 north of the SEB and the other south of the NEB on the following side of the globe, extended all the way across. The scanned image shows them as segments. This and other stuff I put into this sketch also "dropped out".

Seeing conditions plays a very big role, but so does transparency. I usually don't note transparency in sketched notes. That's what makes details look so different from sketch to sketch even if the air stability reads the same. This is especially true for Saturn observations.

I most always use some kind of filter for planetary. In the above sketch I used a specially coated star diagonal that I believe acts like an interference filter.

I never sketch if the conditions are bad. I won't even observe planets for very long if conditions are not favorable either.

Thanks again Jim.

#10 markseibold

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Posted 21 March 2009 - 08:50 PM

Sol

Beautiful sketch work! :bow: :bow: :bow:

I hope to observe soon as weather improves. I just wish I could push my short focal 10.1" f/4.5 Coulter Dobsonian to 300X. With a 5mm super plossl (I have not a barlow) I can produce 240X if seeing is at or near a 10. But my best views have always been with an old 6mm Orthoscopic eyepiece at 192X.

Thanks for posting and your generous offer of your great and useful template.

Mark

#11 Sol Robbins

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Posted 22 March 2009 - 08:59 AM

Mark,

Thanks very much. I hope you get to observe Saturn soon under good conditions.

#12 TenthEnemy

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Posted 22 March 2009 - 09:19 AM

Wow! That's an amazing sketch. Much thanks for the template as well, I'll try to use it if my skies ever clear up...

#13 varmint

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Posted 22 March 2009 - 09:32 AM

Thanks Sol, I may have to try next time with my Yellow/Orange and Orange filters and see if there's much of a difference, though you did mention seeing and transparency play big roles and I'm not in the best position to have good to great conditions for either of those...

Next time I'm out at a dark site...

#14 Tommy5

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Posted 22 March 2009 - 08:47 PM

Great Saturn sketch,good detail across the globe,i though i saw a thin dark line north of the rings the last 3/16/09 i looked but it can be hard to tell as the rings are at such a small angle and saturn sometimes can seem to reverse its orientation as i look at it. Anyway i find a #11 yellow-green filter increases contrast on saturn's globe but this filter always seems to improve images in my colorful achro.

#15 cildarith

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Posted 22 March 2009 - 11:04 PM

Nice work Sol! I'm glad you got a bit of clear weather.

#16 contrailmaker

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Posted 23 March 2009 - 03:05 AM

Sol:

Great sketch as always. I have been observing Saturn quite a bit lately and am also a little perplexed by the dark band which to me also appears to be on the north side. I would have thought that the C ring would not show against the disc because it is so tenuous. However, the current angle can obviously make it more visible. Another possibility is that it may be the shadow of the C ring. There is a good image taken by Bird on May 15 (solar system imaging and processing) that clearly shows the feature but does not shed any more light (so to speak) as to its origin.

I am also curious as to why you did not show the cassini divission in your sketch. I figured it would surely show with your refractor. Cassini is easily seen with my 8" SCT.

cm

#17 Sol Robbins

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Posted 23 March 2009 - 05:50 AM

Thanks again to everybody,

I was hunting for Cassini. Maybe it was the star diagonal I was using. Its dielectric coating acts like a filter and cuts light transmission down to ~60% overall. The good thing is that it seems to work well on Saturn, especially any possibility of discerning NEB rifts.

I reinstalled my Chromacor/regular star diagonal assembly last night. Next time out I'll see if this makes any difference.

Bset,

#18 contrailmaker

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Posted 24 March 2009 - 02:08 AM

Sol:

There are some new pictures posted by chris go on the solar system image section and it looks like the dark band is a shadow of the rings on the globe.

cm

#19 markseibold

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Posted 24 March 2009 - 02:33 AM

CM

Not to detract from Sol's great sketch here but I accidentally drew Saturn that way when its rings were nearly edge on in mid December. Several local friends who looked at the original sketch asked if the cloud band (below the rings here) was a shadow from the rings- Mark >
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#20 Sol Robbins

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Posted 24 March 2009 - 05:46 AM

Hi,

Thanks for pointing towards Chris's image. I guess it may very well be a very thin shadow.

Mark-

That's definitely ring shadow due to the orientation of your drawing. In my sketch south is up.

Thanks,

#21 darkstar528

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Posted 24 March 2009 - 06:29 PM

Great sketch!

These awesome Saturn sketches are pushing me to get a better night scope...I can't settle for a slightly orange disk with wings!...






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