Imaging Jupiter: Lots of dots in my images

Discussions of using SharpCap for Planetary Imaging
Candieman
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Imaging Jupiter: Lots of dots in my images

Post by Candieman » Fri Jul 31, 2020 11:13 pm

I started my post-retirement hobby of astrophotography a couple of years ago, and while I've done pretty well at imaging DSOs, I admit I need some help with planetary imaging. The issue I seem to have over and over again is that my images come out made up of many fine-scale dots, making for a very splotchy pattern. I've seen others do this type of imaging successfully, so I'd like to know if someone can at least give me a clue as to what I'm doing wrong. The latest example is from last night. I used my C925 EdgeHD, TV 2.5x Powermate, and ZWO ASI224MC to image Jupiter (focal length: 5874 mm). The collimation was very good, and I focused on one of Jupiter's moon with a Bahtinov mask, and that looked very good, too. I captured a 60-second video (RAW8, .ser) using SharpCap, fixing the exposure time to 10 ms, and then adjusting the gain to 317 to get the histogram to ~70%. That gave me just over 100 fps. I've seen videos on-line and read discussion forums that indicate that this is the way to do this. However, all the videos I saw on-line resulted in great-looking images, far better than anything I ever get. I've attached here the first image in one of the videos I made last night (it's a screen capture from AutoStakkert.
SampleJupiterImage073020.JPG
SampleJupiterImage073020.JPG (56.32 KiB) Viewed 209 times
When I process my videos through AS (taking the best 10%) and then use RegiStax for wavelet sharpening, I have to crank the Denoise on Layer 1 to 0.4 (or higher), due to the noise that the dots in the original images have in them. This takes away any sharpness of features there may be, leaving me with a very smooth image, smoother than I think I should see. I'm aware that increased gain should lead to more granularity of an image. I'm wondering if this is what I'm seeing, or am I just doing something wrong, or am I expecting too much? This is not a one-time event. This happens all the time when I try to image Jupiter or Saturn. A complicating factor is that I live at 42N, so Jupiter only gets up to about 25 degrees above the horizon at best these days, but I don't think that would be causing dots like these, or would it? Any thoughts or recommendations are appreciated.

BlackWikkett
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Re: Imaging Jupiter: Lots of dots in my images

Post by BlackWikkett » Fri Jul 31, 2020 11:20 pm

Hi Candieman,

First thing I'd say is verify your focus on a star with whatever you normally use. Next I'd verify seeing at your observing location. Last I'd ask if you would share the SER file and give us a crack at processing your data. This is the quickest way to get a sanity check on your process and help illuminate one potential problem.

-Chris

Candieman
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Re: Imaging Jupiter: Lots of dots in my images

Post by Candieman » Fri Jul 31, 2020 11:30 pm

Chris,

In previous imaging sessions, I focused on a nearby star with a Bahtinov mask, and I got the same result. I do lock down the mirror after focusing, too. In terms of sky conditions, I'm considered Bortle 5. There was a slight trace of smoke around last night, but it didn't look significant at all. I wouldn't have any trouble sharing the .ser file, but here can I put it, never having done this before?

BlackWikkett
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Re: Imaging Jupiter: Lots of dots in my images

Post by BlackWikkett » Sat Aug 01, 2020 2:55 am

Candiman,

Bortle 5 is fine but was more referring to seeing conditions or atmospheric turbulence. Here's some astronomy weather sites that provide information.

https://www.astrospheric.com/
https://clearoutside.com/
https://www.meteoblue.com/en/weather/ou ... rts/seeing

To share the .ser file you can use google drive if you have a gmail account. Dropbox and One drive all have free variants. Just make sure you check the service you decide to use sharing conventions and then share the link generated in this post. If you need more help with the sharing just say so, i'll get more detailed if needed.

-Chris

Candieman
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Re: Imaging Jupiter: Lots of dots in my images

Post by Candieman » Sat Aug 01, 2020 5:29 am

Chris,

I put the file (all 1.2 Gb of it) on my Google drive and I think it's shared for you to download, but I'm not entirely sure. Can you give it a try and tell me if you can get it? The link is: https://drive.google.com/file/d/10XA-V_ ... sp=sharing.

Candieman

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turfpit
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Re: Imaging Jupiter: Lots of dots in my images

Post by turfpit » Sat Aug 01, 2020 8:11 am

I processed your download file - this is the result. Software used Autostakkert!3 and Registax 6.

Capture 2020-07-30T23_11_48_lapl6_ap50.jpg
Capture 2020-07-30T23_11_48_lapl6_ap50.jpg (40.84 KiB) Viewed 182 times

The SER file played back looks OK.

SER-playback.JPG
SER-playback.JPG (53.38 KiB) Viewed 182 times


Below are the processing steps, more detail here viewtopic.php?f=35&t=1156 :


Austostakkert-1.JPG
Austostakkert-1.JPG (112.73 KiB) Viewed 182 times

Austostakkert-2.JPG
Austostakkert-2.JPG (100.38 KiB) Viewed 182 times


Select RGB Balance and Auto balance to sort the colour.

Registax-1.JPG
Registax-1.JPG (170.36 KiB) Viewed 182 times

Registax-2.JPG
Registax-2.JPG (200.59 KiB) Viewed 182 times


Dave

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turfpit
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Re: Imaging Jupiter: Lots of dots in my images

Post by turfpit » Sat Aug 01, 2020 8:21 am

I would say your processes for capture - histogram 70%, achieving 100fps - are OK. The 25° elevation is a big factor. At 53°N I get only 14°. The atmospherics and thicker atmosphere will be the major factors against you and in that case the Barlow makes things worse. Maybe try without the Barlow and compare the results.

Dave

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turfpit
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Re: Imaging Jupiter: Lots of dots in my images

Post by turfpit » Sat Aug 01, 2020 11:51 am

Another process of this data. Autostakkert the same, more aggressive Registax settings. Unzip the file to access settings.rwv. You can use Load Scheme in Registax to directly apply these settings to the image.

v2a.png
v2a.png (240.47 KiB) Viewed 175 times

v2a-RS6-settings.JPG
v2a-RS6-settings.JPG (43.45 KiB) Viewed 175 times

settings.zip
(289 Bytes) Downloaded 7 times


A comparison. The right image is pushing the boundaries of using noise (aggressive settings) to create data. Somewhere in-between is probably more realistic, that comes down to personal preference.

comparison.JPG
comparison.JPG (23.32 KiB) Viewed 175 times


Dave

BlackWikkett
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Re: Imaging Jupiter: Lots of dots in my images

Post by BlackWikkett » Sat Aug 01, 2020 4:08 pm

Looks like Dave has done everything I would have done and provided you with some processing guide lines to follow and tweak as needed. Thanks Dave! Good luck processing!

-Chris

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oopfan
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Re: Imaging Jupiter: Lots of dots in my images

Post by oopfan » Sat Aug 01, 2020 9:34 pm

Awesome, Dave!

Brian

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