Io with shadow and red spot

Quopaz (Nick) · #1 20-07-2020, 05:00 PM

Another one from last night. Conditions were tricky, there was some very good seeing around, but the clouds kept getting in the way and it was a bit windy. Very frustrating to get half way through a video and then suddenly have the image go dark, then light, then dark again. I couldn't get a good full 3 minute video until the transit was almost over, then there was a patch where it was OK for a while. Managed to get this one:

Quopaz (Nick) · #2 20-07-2020, 08:34 PM

This pic was taken a bit earlier. Taken from a short 30 second video, the first 20 seconds were good then it went dark (clouds). So all I got was a 20 second gap in the clouds. Lost the next half hour or so due to total cloud cover, right when I wanted it to be clear. Not as many frames as I would have liked, but still made a pic out of it:

Saturnine (Jeff) · #3 20-07-2020, 11:18 PM

Thanks for posting Nick, you are still getting better seeing than I'm getting, has been crap for weeks here. Wanted to catch the Io transit last night but the one video I did take was too horrible to bother processing. Was struggling to see the 2 main Temperate Belts let alone shadows and Red Spot.

Quopaz (Nick) · #4 22-07-2020, 01:54 PM

Yeah it's hard this time of year in the middle of Winter. The last 2 nights have been no good with total cloud cover. Hoping tonight might be better, meant to be about 50% cloud. Here's a couple more from this session- the first just a plain one before the shadow and red spot came around. The second after the moon was past the edge, but with the shadow still there.

Merlin66 (Ken) · #5 22-07-2020, 03:43 PM

Nick,
Very impressive result! Well done.
What scope etc did you use?
[edit] I see from a previous post: Using Skywatcher 10" dob, Canon 60D DSLR camera.

Quopaz (Nick) · #6 22-07-2020, 03:55 PM

Hi Ken, thanks, it's a Skywatcher classic 250P (10 inch solid tube) dobsonian. I modified it by getting the dobsonian upgrade kit, so it now has the goto/synscan tracking system. I also replaced the standard focuser with a 10:1 dual speed focuser. Camera is a Canon 60D DSLR. Using PIPP, stacking with AS!2 and Registax to sharpen.

Merlin66 (Ken) · #7 22-07-2020, 03:58 PM

Thanks Nick.
How to do handle the video file format from the Canon?

Quopaz (Nick) · #8 22-07-2020, 07:03 PM

The video file format from the Canon is .mov. I run the videos through PIPP (Planetary Imaging Pre Processing) and this converts them to .avi format, which can be handled by Autostakkert!2. PIPP also does several other things. I normally do cropping so that AS!2 runs faster, also center the planet in each frame and enable quality estimation- I generally select 90%.

Merlin66 (Ken) · #9 22-07-2020, 08:52 PM

Have you considered ImPPG to tweak the images?

Quopaz (Nick) · #10 22-07-2020, 10:11 PM

Haven't heard of it but I'll look into it, thanks. I've just started trying to use Winjupos to de-rotate, but don't fully understand how to use it yet.

Tulloch (Andrew) · #11 23-07-2020, 09:36 AM

Nice images, but have you thought about your color cast? Jupiter looks a little green to me ...

Have you tried using AS!3? It's apparently a significant improvement over AS!2, don't be put off by the comment that it is in beta mode, it's been like that for 5+ years. Emil is also currently working on AS!4, due ??? When I was using my Canon DSLR for planetary, I also used PIPP for cropping and centering the frames, but I let AS!3 work out which were the best frames - each to their own

Again when I was using my DSLR, I de-rotated my videos to remove the field rotation in WJ but eventually I stopped since I couldn't see much difference. Christophe Pellier has a great presentation about imaging the planets with an alt/az Dob and WJ, see link below. He also has some great tips about planet colours on his website.
https://www.planetary-astronomy-and-...zimuth-dobson/

Andrew

Quopaz (Nick) · #12 23-07-2020, 12:33 PM

Thanks Andrew, I should mention that I am colourblind (red/green) which makes it hard, so I try not to alter the colours too much anymore after I showed my sister some pics and she said she liked the pink saturn!

Haven't tried AS!3 yet, but am finding AS!2 to be better than stacking with Registax, which is what I used to do.
I also haven't been able to see much difference with WJ yet, but it might be something that could make a difference with more practice. I'd like to be able to join 2 or 3 x 3 minute Jup vids together and de-rotate, but not sure if it can do that. Thanks for the link.

Tulloch (Andrew) · #13 23-07-2020, 01:12 PM

Aah, that makes a difference

AS!3 is (by all accounts) much better than AS!2 so well worth upgrading to.

Registax has a very good Auto-RGB tool which works well for Jupiter (as there is a good colour range and some nice white points), I hope you don't mind but I have taken the liberty of taking one of your images (using a simple screen grab) and applying the auto-RGB tool in R6 to it (see attached). You may not notice the difference, but it looks better to me. Maybe it's a little pink, but you should be able to do better with the actual captured image, not just a screen grab from my monitor.

I have found that with my system, once I have found a good colour balance for my images (and the auto-RGB settings for Jupiter is a good start), I apply the same colour correction to all my images. So in your case, maybe a similar colour correction (r1.07 g0.95 b1.08) could be applied to the other planets as well. You could look at a number of your Jupiter images and see if they all give similar colour shift values and find a typical result.

I find it very difficult to combine different captures together in WJ, primarily due to the field rotation between sessions. Unless you align the images perfectly, the resulting de-rotated stack in WJ is worse, not better. I used to take 10000 frames (at 20fps under Backyard EOS) over about 8 minutes, link them together into 1 long video in PIPP, derotate in WJ (both field and planetary de-rotation) and stack the result in AS!3. It took a long time in WJ, and the result really wasn't much different from when I stacked 5000 frames directly in AS!3. You may have more success than me however ...

Hope this helps,

Andrew

Quopaz (Nick) · #14 23-07-2020, 05:15 PM

Thanks heaps for that Andrew, I can see the difference but what I see would be different to what people with normal colour vision would see. I have noticed that your Jupiter pics have a different colour to mine, to me yours look a bit more blue and I'd like to get mine that colour. Hopefully those colour settings work on all my Jupiter pics, thankyou.

Quopaz (Nick) · #15 23-07-2020, 09:35 PM

How's the colour on this one now after a RGB auto balance, better or worse?