Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Saturn and the Seeliger Effect

  • Please log in to reply
8 replies to this topic

#1 David Gray

David Gray

    Vanguard

  • *****
  • topic starter
  • Posts: 2,023
  • Joined: 06 Aug 2012
  • Loc: Ower Yonder 01.5ºW. 55ºN (UK)

Posted 02 August 2021 - 07:46 AM

True to the weather forecast last week we had a good clear night (and with very good conditions) – even if they had backtracked on that forecast the preceding 12-hrs........time and again this happens  - what is wrong with them.....??!!

 

The sketch, c.1 hour before opposition, shows the Seeliger Effect with the Rings.  The extreme contrast with the Globe dullness often gave me the impression that there is an inverse Seeliger going on in Saturn’s atmosphere....??  Such is how the eye-brain reacts to relative contrasts; and to render that I cannot show the brightness any higher than the whiteness of an already very white paper.  The only recourse is to dullen the Globe; and that seems to offset somewhat with the tinting procedure.

 

Interesting how that bluish South Hemisphere seems to have taken on a more bronze cast! 

 

Again one of several, it seems around the planet, EZ(N) intensifications/w.spots,..... Dave.

SAT 2021 August 2 0110.jpg


Edited by David Gray, 02 August 2021 - 08:06 AM.

  • Special Ed, gfeulner, John Rogers and 18 others like this

#2 niteskystargazer

niteskystargazer

    Cosmos

  • *****
  • Posts: 8,736
  • Joined: 05 Oct 2009
  • Loc: 41-43'-28" N 87-42'-39" W

Posted 02 August 2021 - 10:01 AM

David,

 

Good sketches of Saturn (And the Seeliger Effect) smile.gif .

 

CS,KLU,

 

thanx.gif ,

 

Tom



#3 frank5817

frank5817

    Hubble

  • *****
  • Moderators
  • Posts: 17,146
  • Joined: 13 Jun 2006
  • Loc: Mesa, Arizona

Posted 02 August 2021 - 10:16 AM

David,

 

The Seeliger Effect is clearly demonstrated in your sketch comparison between June and August.

Superb sketching.

 

Frank :)


  • Aquarellia and flt158 like this

#4 astronz59

astronz59

    Apollo

  • *****
  • Posts: 1,356
  • Joined: 15 Sep 2010
  • Loc: Auckland, New Zealand

Posted 03 August 2021 - 03:00 AM

Outstanding Dave! love the color matching! bow.gif waytogo.gif



#5 Uwe Pilz

Uwe Pilz

    Gemini

  • *****
  • Moderators
  • Posts: 3,346
  • Joined: 16 May 2008
  • Loc: Leipzig, Germany

Posted 03 August 2021 - 05:07 AM

It is not too late to see the opposition effect. Even a small scope will do it.


  • David Gray and flt158 like this

#6 Gregrox

Gregrox

    Vostok 1

  • *****
  • Posts: 134
  • Joined: 14 Oct 2020
  • Loc: Peidmont Triad in NC

Posted 03 August 2021 - 08:13 AM

Now that you mention Saturn seems duller rather than the rings brighter... on July 31st around 1-2 AM EDT, I observed Saturn. It did seem to have a duller color, like darker mustard rather than pale butterscotch. How obvious is the Seeliger effect just a few days before opposition?



#7 Special Ed

Special Ed

    Voyager 1

  • *****
  • Posts: 11,406
  • Joined: 18 May 2003
  • Loc: Greenbrier County, WV 38N, 80W

Posted 03 August 2021 - 09:28 AM

Dave,

 

I agree with Frank--you show the Seeliger Effect nicely with these drawings.  It's also interesting to note some other differences between the two observations, e.g. the globe shadow on the rings is gone and the ring shadow on the globe is much diminished.  Nice work!

 

When I last saw Saturn on July 28th, the seeing was poor and wildfire smoke from the fires out West and Canada affected the transparency substantially so the brightening of the rings was subdued (and I could only detect 3 moons).  I might get another look tonight--hope so.

 

To try to answer Gregrox's question--I have heard that the rings appear brighter for a few days on either side of opposition--don't know if that's true, but it makes sense.  Btw, your view on the 31st might have been affected by wildfire smoke, too. 


  • David Gray likes this

#8 David Gray

David Gray

    Vanguard

  • *****
  • topic starter
  • Posts: 2,023
  • Joined: 06 Aug 2012
  • Loc: Ower Yonder 01.5ºW. 55ºN (UK)

Posted 03 August 2021 - 10:11 AM

Many Thanks All for the Comments and Likes.....smile.gif

 

Now that you mention Saturn seems duller rather than the rings brighter... on July 31st around 1-2 AM EDT, I observed Saturn. It did seem to have a duller color, like darker mustard rather than pale butterscotch. How obvious is the Seeliger effect just a few days before opposition?

Pretty sure the ring effect is real.  In particular as I spend a deal of my observing (>5 decades) noting colour and tonalities and the changes in the rings becoming more marked as opposition approaches.  Also it is the worst time to seek those minor divisions.

 

https://en.wikipedia...pposition_surge

 

As to whether the Globe/atmosphere does a sort of Inverse Seeliger – not seen any professional comment/studies on that; but can’t help wonder the relative comparison being so marked. 

 

With Jupiter I’ve seen a similar effect of the globe looking similarly drab – dull shades of olive browns etc.(almost looking grimy!)  – when adjacent to the bright side of the Moon during occultations.

 

As Uwe says the effect will be a few days yet (my old 3-inch refractor shows it well); but it seems (other apparitions) that the relative Globe-tonality vs the Rings ‘recovers’ more quickly.  If it is a real effect with Saturn’s atmosphere the Sun-Earth-Planet angle must be more critical.......??!


Edited by David Gray, 03 August 2021 - 10:13 AM.

  • Quinnipiac Monster likes this

#9 Asbytec

Asbytec

    Guy in a furry hat

  • *****
  • Posts: 18,831
  • Joined: 08 Aug 2007
  • Loc: Pampanga, PI

Posted 13 August 2021 - 06:21 PM

David, your observation is nothing short of amazing. 




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics