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Green planets

Posted: Tue Aug 25, 2020 3:59 pm
by Pete
Monday, 24 Aug 2020

Jupiter and Saturn are brilliant in the early evening, and although a bit low hopefully the seeing will be typical of a slightly humid summer night.

The SBIG’s stripped from the 14 and Altair’s centered using an illuminated reticle eyepiece. The eyepiece’s than moved to the 80mm long-tube guidescope and the guidescope’s centered as well. (With the tiny planetcam chip it an be challenging to put a planet in the FOV at 3550 mm FL.)

Slewing to Jupiter and carefully centering on it, the Celestron NexImage 5 is mounted on the 14. Several 3,000 image AVIs are run later processed thru Registax. Jupiter has a green cast to it. As to why, I’ve no clue.
Image
With heavy PhotoShop processing the color is a bit better. And the great red spot is red. On the left, Europa (higher) and Io (lower) look like they’ve been run thru a prism  Of course, making the images smaller would help a whole lot.

Saturn is a good bit dimmer and even with gain maxed out exposures are only 1/32 or 1/50 second whereas Jupiter was imaged with 1/72 second exposures.
Again 3,000 frame AVIs were subsequently processed thru Registax. Garbage in, garbage out.
Image
Color was strange. Processed the green tint out but this is not accurate either.

Conclusions & lessons learned:

Although stars weren’t twinkiling seeing wasn’t good.

Not sure that I learned much tonight, other than that the Celestron planetcam seems to be off-color and that R, G & B seem to be misaligned. Unable to use the Registax color alignment tool to correct things.

Re: Green planets

Posted: Tue Sep 01, 2020 12:18 pm
by TimW
Are you using the correct bayer pattern?

Re: Green planets

Posted: Tue Sep 01, 2020 12:23 pm
by NGC7000
That's what I was wondering. I'm pretty sure ZWO cameras are generally RGGB.

Re: Green planets

Posted: Tue Sep 01, 2020 12:26 pm
by TimW
I have a ZWO camera with bayer pattern GRBG.

Re: Green planets

Posted: Tue Sep 01, 2020 12:37 pm
by Bruce D
Tim was over with his camera and i had my new ZWO camera (different model) and i was having fits trying to get an image until Tim suggested trying different bayer patterns, bingo! Not all ZWO cameras use the same pattern

Re: Green planets

Posted: Tue Sep 01, 2020 2:43 pm
by NGC7000
Do you remember which one yours used, Bruce? It might be the same as mine.

Re: Green planets

Posted: Tue Sep 01, 2020 4:01 pm
by Bruce D
Haha Tom, being a bit dyslexic i can't tell one from the other. Every time i use the camera i have to try the 3 options until I get a usable image. Generally when it's wrong i don't get anything recognizable, just a weird cross hatch pattern. Do we both have the same camera?

Re: Green planets

Posted: Tue Sep 01, 2020 5:32 pm
by Pete
Good call on Bayer matrix. Suspect you're right.

The AVIs on these green planets were stacked and processed in Registax 6, because I hadn't yet figured out how to use AutoStakkert. In Registax 6 there is a little button called "Show Prefilter" that allows the selection of "Bayer method". And this may have been the problem. Accidently erased the green planets. Too bad I can't check the original AVIs as that'd answer the question. But then again, the question's probably answered as I didn't notice the discoloration when imaging and probably would have.

In AutoStakert there is also a Bayer selection. Didn't see a big problem with Luna and Mars from Sunday night so the "auto select" probably worked. I can force it to RGGB and I have.

Thanks for the help Tim.

Re: Green planets

Posted: Tue Sep 01, 2020 5:46 pm
by TimW
I use PIPP for debayering, then Autostakkert for stacking, then Registax to adjust the wavelets.
Jupiter with spot.jpg
Jupiter with spot.jpg (23.63 KiB) Viewed 406 times

Re: Green planets

Posted: Tue Sep 01, 2020 6:04 pm
by Bruce D
Great image Tim!