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Jupiter 9.11.2012 - first time seeing oval BA

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#26 Sasa

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Posted 14 January 2013 - 03:28 AM

It is probably not worth starting new thread, so here is a short update. Finally, I was able to observe Jupiter through AS110:

Posted Image

Following the discussion about thermal effects, it looks like, unfortunately, that this old lens (from 1924) has serious problems at low temperatures (it was -9C at the time of observing). During summer, the optics was almost perfect (with only mild traces of undercorrection). In last autumn session, I already noticed very faint brightening in the first diffraction ring which was a little bit confusing when I was observing close unequal doubles stars. But two days ago, Jupiter moon's were accompanied by two relatively bright stars. Star test showed clear signs of pinched optics. Still, Jupiter was very nice and clean. I could observe a lot of details.

#27 Asbytec

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Posted 14 January 2013 - 11:58 AM

You have a lens that old? Wow. :)

In any case, yes, it's a nice observation, Sasa. I've been hitting some doubles lately, too. Tight unequal pairs. They are interesting and challenging...and taking up all my time.

#28 ericj

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Posted 23 January 2013 - 10:16 PM

Hi Sasa,

Very nice sketches, you recorded a lot of fine detail.

Here is some background information on oval BA.

In the late 1930's, three white ovals formed in Jupiter's South Temperate Belt (STB) and were designated as FA, BC and DE. Ovals BC and DE merged in 1998 formed the oval BE. These two ovals merged in March 2000 and formed oval BA.

Since 2000 BA has remained white in color, but at the end of 2005 oval BA began to change to a brown color, and on February 24, 2006 Filipino amateur astronomer Christopher Go noted that its color changed to that of the Great Red Spot. Dr. Tony Phillips gave it the name "Red Spot Jr." or "Red Jr." although professional astronomers still refer to it as oval BA.

Here is a link to my Jupiter Nomenclature page that shows BE and FA before these two ovals merged in March 2000 and formed oval BA:

http://ejamison.net/...menclature.html

And here are two sketches I made of oval BA in 2006:

http://ejamison.net/jupiter052806.html

http://ejamison.net/jupiter061606.html

Hope this helps.

Best,

Eric Jamison

#29 azure1961p

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Posted 24 January 2013 - 09:10 AM

Eric nice of you to mention the history on the white ovals leading up to BA. Unlike the white ovals we have now that trio was far more conspicuous and was seen even in average seeing. It was fun to watch how they shuttled about. Even a few nights passing and they were noticeably rearranged. The spots now though - wow - tinier and far less conspicuous. They'd morph into a specked muddle then smooth out into nothing leaving the surrounding grey spaces between the spots as the greater albedo. Those older pre BA spots, fat and bright. Small still but definately bigger than these micro spots we have now.

Pete

#30 Sasa

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Posted 25 January 2013 - 05:30 PM

Eric, it is very interesting. I had no idea about the origin of the "Red Jr.". Thanks for the story.

#31 ericj

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Posted 29 January 2013 - 10:35 PM

Hi Pete and Sasa,

Glad to hear you found the information helpful.

Best,

Eric

#32 Rich (RLTYS)

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Posted 30 January 2013 - 09:32 AM

Here's an image I took of Jupiter last evening, 1-29-13, using the Slooh Remote Observatory. Oval BA is clearly seen.

Rich (RLTYS)

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