2 Saturns, 2 sizes & 2 times..!

[Kokatha man 1,462]

Hi, I thought whilst playing with RV6 and (still!) waiting for the weather to give us an opportunity to image I'd have a look at how Saturn presented itself in my C11 over 2 seperate imaging sessions: one image from the 15th Jan and the other from 28th March.

Discrepancies will arise due to using different capture settings now than then apart from seeing etc, principally I use much more gamma and lower histo settings now.....and I wasn't going to repro them again so, I just took the psd files I had and made adjustments for apparent diameters.....so there are also some processing differences also.

On 15th Jan Saturn was 17.7 arcsecs and on 28th Mar it was almost at its opposition diameter of 19.3 arcsec.

I've approximated their relative sizes reasonably accurately and their visual renderings aren't too different for the purpose of this thread.

The "Seeliger Effect" is one very noticeable aspect in the later (rhs) image.....I thought it interesting to post these side-by-side comparisons 72 days apart!

Edited April 5, 2011 by Kokatha man

[brianb 23]

Very nice images and a most interesting comparison! Thanks for posting.

[Kokatha man 1,462]

Thank you Brian.....here's another showing Saturn on 24th Feb (local date) sandwiched between those other 2, but I had to reduce the filesize & sizing correspondingly....!

Just set your screen resizer to 125-150% before clicking on the image for best viewing - the Seeliger Effect (Saturn's rings brightening as it approaches opposition) shows a progressive increase in brightness/whiteness across the images from left to right!

Edited April 5, 2011 by Kokatha man

[AztecastroMcJ 14]

great comparisons KM

easy to see size difference

also noticeable is ring angle tilt change aswell

14th Jan tilt was 10.2degrees 27th march tilt was 8.9 degrees,

thx for posting

James

[Kokatha man 1,462]

also noticeable is ring angle tilt change as well

14th Jan tilt was 10.2degrees 27th march tilt was 8.9 degrees,

thx for posting

James

Thanks for bringing that to my attention James.....of course you're right, that was one of the ring aspects that had completely slipped my mind..!

[luis 15]

EXCELENT !!! Incredible detail

[Pete Presland 10,101]

lovely sharp images!

[oldfruit 126]

Great images and very informative, especially about the rings brightening. I had read about this but was unable to get out with the scope at the time so am glad you have posted this so i can see what i was missing. Thanks for sharing.

[Kokatha man 1,462]

Thank you Luis, bg1 and o/f.....this thread was a bit old until Luis dug it out of the vault, but I think that the 28th March image is one of the best I have been fortunate to capture, even if I wasn't overly rapt in the seeing.

I only say that because I'd have put the seeing at around 8/10 for a very brief "window' around that particular image's capture: I'm still waiting for one of those "special" nights where it definitely goes above 8/10.....or even just stays at that quality for a little while to maximise the capture possibilities - but wishing and reality are often 2 different things....!

One of the problems I've encountered in all my captures of Saturn this apparition is that there have allways been 1 or 2 channels where the capture is of high quality, usually red being the best, but the remaining 1 or 2 channels are somewhat lesser in quality...but that's imaging for you..!