LiveStack histogram

Somewhere to ask questions about the best way to use SharpCap
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snubem
Posts: 12
Joined: Mon Jul 09, 2018 3:45 pm

LiveStack histogram

Post by snubem » Sat Aug 03, 2019 2:14 pm

Robin,
I will PA and get rid of the black screen on top of the image.

ZWO183 non cooled camera, 8" SCT/.63 reducer on a CGEMII in Bortle 8 downtown Chicago.
I'm at 300 Gain, 5 sec EXP. Flats and Darks applied. I Save Images as seen.
Looking at my Histogram, what are your suggestions to improve my image?
Increase the EXP or decrease Gain or...?

Thank you for getting me headed in the right direction.
Greg
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admin
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Re: LiveStack histogram

Post by admin » Sun Aug 04, 2019 1:11 pm

Hi,

The best way to get an accurate answer for what gain and exposure settings you should use with your particular equipment and light pollution levels is to use the SharpCap Smart histogram features which you can find details of in the user manual here https://docs.sharpcap.co.uk/3.2/#Smart%20Histogram

Hope this helps, Robin

JimsShed
Posts: 8
Joined: Sat Feb 24, 2018 7:25 am

Re: LiveStack histogram

Post by JimsShed » Sun Aug 11, 2019 2:08 am

Aren't we a picky bunch, always wanting more, and I'm as guilty as the next. What would Mr Hubble think if he saw what we can do now :)
Greg yes use Robin's suggestion of the smart histogram function. It's fantastic.
You seem to be doing very well for your conditions and 5 second exposures. Are you also using a filter?
Black banding (across the top) can be reduced with better tracking/polar alignment. This banding will also be influencing the histogram and colour balance.

Jim

snubem
Posts: 12
Joined: Mon Jul 09, 2018 3:45 pm

Re: LiveStack histogram

Post by snubem » Sun Aug 11, 2019 1:57 pm

Jim,
I'm transitioning from my 8" Goto Alt-Az Evolution to the 9.25 EDGE HD on a CGEMII. I have a lot to learn.
That image was only aligned with StarSense on the 8"/CGEMII. I'll PA net time to get rid of the black line. I can't always PA due to LP and lack of stars.
I haven't used my LP filter much due to having to increase my lights by prolly 4x's.
Once I get PA'd, I'll acquire 5 secs lights as a baseline, then I'll increase the times, then add the LP filter.
Good experiments!
I tried the Smart Histogram 3x's with my 183MC on my 2TB SS drive and it kept getting hung up on the last stage.
I'm using my attached cheat sheet as my guide for the histo.

I just found out that the spacing for my 183MC should be 105mm from the sensor. I'm not even close to that. I'm only using my .63 reducer / 183MC. I have the correct spacers coming from HP. I hope that improves image quality.
Thx,
Greg
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donstim
Posts: 60
Joined: Wed Sep 19, 2018 5:35 am

Re: LiveStack histogram

Post by donstim » Mon Aug 12, 2019 7:27 am

Greg,
I'm curious. Exactly what are you trying to improve about your image?

From your display histogram, it looks like you could be clipping the black level. You may be able to regain some lost nebulosity by moving the black level slider slightly to the left. Of course, you may have already examined that and prefer the black level you selected.

I've never seen the white level adjusted so far to the left. Could you help me understand the reasoning behind the selected white level? Without being able to see how changing it affects the display histogram, I can't tell if you may also be clipping whites.

If you have trouble getting the brain to work, maybe just try a couple different exposure settings (maybe 10 sec next time)?

Don

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