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Jupiter 2-7-13

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#1 yock1960

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Posted 07 February 2013 - 10:52 PM

Balmy night tonight and even better...the Red Spot is visible and collected about 80 gigs of data! I want to say the seeing was better tonight than last night. Here is a quick process from about the middle of my session. I will be working on this data for a while I think!

50% of 4865 frames @ 40FPS, stacked in As!2 and processed in Pixinsight using ATrousWaveletTransform, UnSharpMask and CurvesTransform.

Steve

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#2 Tassydevil

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Posted 08 February 2013 - 12:49 AM

Very nice Steve.

#3 Freddy WILLEMS

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Posted 08 February 2013 - 01:00 AM

Great, Steve try to resample 3X.

#4 Kecktastic

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Posted 08 February 2013 - 01:48 AM

Looking good Steve, some nice detail in there.

Cheers
Trevor

#5 yock1960

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Posted 08 February 2013 - 05:25 AM

Thanks all!


Freddy, The other day I tried the 1.5x drizzle option in As!2. It turned out reasonably well I thought. I may try that tonight, it was too late last night.

Steve

#6 Eddgie

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Posted 08 February 2013 - 10:25 AM

Thanks for posting. I was out last night viewing Jupiter and was hoping someone would post a picture so I could use it to confirm my visual observations.

Nice imgage, and confirms my observations nicely. I was lookng for ovals in the south but could not find any, and was disappointed. Your image shows though that none where really prominent enough to see.

The eddy structure following GRS was fantastic, and your image captures it well.

Thanks again for posting.

#7 yock1960

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Posted 08 February 2013 - 11:15 AM

Thanks Eddgie!

Not sure if you're talking about the whiteish ovals sometimes seen. I've not been able to bring them out very well to this point, even when they are easily seen in other images; not sure why.

Steve

#8 Eddgie

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Posted 09 February 2013 - 02:26 PM

The little oval train that has been sliding along below the Oval BA are pretty small and have pretty low contrast My estimate is tha they are only about one arc second or so. This makes them pretty difficult even in a C14, and I don't think I have ever seen ovals this small in my 6" APO.

Even when they are well positioned, they can be be difficult for me in the C14. Well positioned means on the meridian. If they are to far off to one side or the other, they get foreshortened and get even smaller and just loose to much contrast (the more oblique the are, the more contrast is lost because contrast transfer is a function of angular size... The narrower you make it the more contrast is lost).

In the C14, ovals generally have to be maybe 1.5 to 2 arc seconds to see well. A bit bigger for the 6" APO. 2 arc seconds or a bit bigger and they come into view.

But so much depends on the contrast.

Notice that an observer using a a fairly small scope can easily see the small dot from a shodow transit of Io even though it is only 1.1 arc seconds..

But the difference between Io's shadow and an 1.1 arc second oval is that the shadow starts with much closer to 100% contrast against the bright background of Jupiter's cloud tops than an most ovals start with. A small scope might loose 75% of the contrast from the shadow, but with 25% contrast difference, it will still stand out from the background.

But an oval that starts out the same size, but with only 20% contrast will loose the same 75%, and that will put its remaning contrast at 5%. This is below the contrast sensitivity threshold of the dark adapted eye for most observers.

The bigger the scope though, the less contrast is lost for small details, and the more likely it is to be seen.

But a 1.1 arc second oval with 20% contrast is a very difficult target visually even in a C14. Seeing has to be just about perfect, and the oval has to be well placed.

I have seen occasional large ovals in but a C11 and a 6" APO, but they had to be pretty big and pretty well placed.

Camera's (and maybe more importanly software) make it easy to detect things that are very hard visually.






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