Jupiter 9.11.2012 - first time seeing oval BA
Posted 14 January 2013 - 03:28 AM
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.
Posted 14 January 2013 - 11:58 AM
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.
Posted 23 January 2013 - 10:16 PM
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:
And here are two sketches I made of oval BA in 2006:
Hope this helps.
Posted 24 January 2013 - 09:10 AM
Posted 25 January 2013 - 05:30 PM
Posted 29 January 2013 - 10:35 PM
Glad to hear you found the information helpful.
Posted 30 January 2013 - 09:32 AM