Very poor stacking results...

Somewhere to ask questions about the best way to use SharpCap
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Re: Very poor stacking results...

Post by descott12 » Sun Jan 06, 2019 4:00 pm

Hello all,
Your feedback has really helped. I got a Bahtinov mask and a motofocus and that really helped. I have also learned alot more abuot using the histogram.
Attached a my latest M42 (19 minutes, gain about 200, exp 5-10 seconds), M31 (8 minutes, gain 200, exp 5 seconds) and a view of my Bahtinov focus image. I didn't use the focus tool in SC. I just changed to focus with the exposure at about 500 ms and watched the image improve.

Still a long way to go but it is nice to see an improvement so quickly
M42_00001_WithDisplayStretch.png (435.67 KiB) Viewed 404 times
bahtinov.png (761.37 KiB) Viewed 404 times
small.png (672.6 KiB) Viewed 405 times
Last edited by descott12 on Sun Jan 06, 2019 4:13 pm, edited 1 time in total.

Posts: 39
Joined: Mon Dec 17, 2018 2:32 am
Location: Charlotte, NC USA

Re: Very poor stacking results...

Post by descott12 » Sun Jan 06, 2019 4:11 pm

Since this was somewhat unrelated to the original thread's topic, I removed the photos and started a new thread for this post. Unfortunately,
this post cannot be deleted...
A few more learning opportunities that I am hoping you can help with.

1. In the M42 screenshot, the histogram looked good until about 16 minutes then a hump developed at the left side that I kept having to clip off my moving the black level to the right. Note also the bluish background tinge. My focus appears a bit off at that point but I think clouds had rolled in. What is the cause of the hump and is that related to the background bluish coloration? I seem to have that issue in most of my stacks. The background is not black but usually has blue tinge.

2. Running man - The color balance was way off and I noticed that the RGB peaks were not overlaying as I think they should. Should they pretty much overlay? and if yes, what causes them to diverge? I tried using the auto-color correction buttons but they often made it worse or caused the problem to begin with. Adjusting the vertical RGB sliders really didn't have the effect I wanted and a very small decrease in blue, for example caused the image to turn alien green.

3. There are three histograms
> The one used during live stacking
> The one in the lower right corner
> The one that you get to from the tool bar that has the Brain

They seem to have subtly different effects. Are they intended for different uses? I know the main menu one is only available when not live stacking.

Thanks in advance
Last edited by descott12 on Tue Jan 08, 2019 3:09 pm, edited 4 times in total.

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Re: Very poor stacking results...

Post by turfpit » Sun Jan 06, 2019 7:14 pm


Glad to see it is progressing for you now.

Time to look more at your settings. Try this
  • Set gain, brightness, exposure as per one of your images above..
  • Set Colour space=RAW16, Output Format-FITS
  • Turn on the Histogram from the toolbar and check the log box.
  • Capture a single frame.
  • Upload a screenshot of the loaded FITS frame, SharpCap screen, camera settings file.
You are aiming for a histogram which looks like Deep Sky - Logarithmic at ... %20Quality

Have a look at and put your camera into the Search at the top. Note the settings used from images you like.

Check here for your scope. Note the settings used.

Look in the SharpCap Gallery - you should find postings from @mAnKiNd and @BlackWickett helpful.

According to Starizona's website, the Hyperstar info an F10 scope is converted to f2 and can capture data 25 times faster. You will need to allow for that.

I am sure some experienced Live Stackers will be along to offer useful advice.


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