JUPITER in the big blue 7/2/06

Robert_T · #1 07-02-2006, 09:17 PM

Hi All, Jupiter's been playing hard to get, AGAIN. I'm losing count of the number of time I've set the alarm for 4am only to find cloud, rain, or worse, a clear sky that clouds up just as I get the neximage fired up

. This morning was no exception. Full cloud cover at 4am so went back to bed. Got up to yell at the dog at 5am, found a miraculously clear sky and fell over myself trying to get everything up (lucky the scope was well cooled) and running while the sky rapidly brightened into blue, rushing focus etc and snapping of four avis at a range of exposures. Seeing was good at 7/10.

Bit dissapointed when I processed though that while there's a reasonable amount of detail, there's an annoying onion-ring effect that comes out no matter what I do on each AVi. I'm aware this happens with under-exposure, but these weren't, at least by the light meter - the one here was running 225 on the light meter in K3CCD tools. All I can think is that with the sly brightness this created the same effect as under-exposure or something. Anyone got any ideas, doubt the avi's can be salvaged?

Anyway, pity as it would have been a decent enough shot otherwise.

cheers,

davidpretorius · #2 07-02-2006, 09:37 PM

i believe that the emerging daylight would not have helped.

http://www.iceinspace.com.au/forum/a...achmentid=9245

the after 6am ones in normal mode you can see onion rings and yet before 6, they are fine at 20 fps!!

iceman (Mike) · #3 07-02-2006, 10:30 PM

I agree with DP, the lack of contrast thanks to daylight probably didn't help. But normally I find the onion rings with underexposure.. What were your gamma and/or other settings?

There's some good data in the image still, well done!

Robert_T · #4 08-02-2006, 07:30 AM

Mike, I had Gamma set to around 60% and Saturation pushed to nearly 90% to try and get some colour (maybe that has something to do with it too). I tried exposures at 1/30th sec and 1/20 sec so varied gain to suit from arond 30% to 20%.

Will have to have a go "in the dark" and see if the problem goes away... don't want it happening when that 9/10 seeing night come along

cheers,

asimov (John) · #5 08-02-2006, 06:24 PM

Nice image anyway Robert. I had a quick play & there was no way known I could process the onion rings out.

Heres something to think about...How come I had no onion rings on my last lot of venus shots that were shot in broad daylight? Is it because venus was in phase or perhaps because theres no surface/atmosphere details present.

jjjnettie (Jeanette) · #6 08-02-2006, 06:34 PM

Excellent detail!

RB (Andrew) · #7 08-02-2006, 06:41 PM

Good image there Robert, like Ice said it's still got some good data.

Robert_T · #8 08-02-2006, 09:09 PM

Quote:

Originally Posted by asimov

Nice image anyway Robert. I had a quick play & there was no way known I could process the onion rings out.

Heres something to think about...How come I had no onion rings on my last lot of venus shots that were shot in broad daylight? Is it because venus was in phase or perhaps because theres no surface/atmosphere details present.

Thanks for trying DP. Not sure with Venus, but expect it's a contrast thing. Venus is so bright it still is very sharply constrasted even in a light sky?