Live Stack with Flat Frame Bug?

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GaryS
Posts: 47
Joined: Sun Mar 31, 2019 5:18 pm
Location: Boston, USA/Jackson Hole, USA

Re: Live Stack with Flat Frame Bug?

Post by GaryS »

Thank you Chris.

As the evening progresses, do you need to redo the Flats as the focus shifts a bit? Is the Flat that sensitive to small tweaks in focus? I also hear others taking about not realigning the camera - does a tiny shift in that from when the Flat was done invalidate the Flats?
Best,
Gary
BlackWikkett
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Joined: Sat Jun 23, 2018 8:48 pm
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Re: Live Stack with Flat Frame Bug?

Post by BlackWikkett »

GaryS

I usually don't redo the flat unless something in the image train changes. For example if I change filter. I've been very very lucky with my main scope a GSO based 6 inch RC. I also have a Moonlight focuser which has made all the difference. Once I focus at the beginning of the night the temperature in NE Georgia, USA doesn't change that wildly.

-Chris
GaryS
Posts: 47
Joined: Sun Mar 31, 2019 5:18 pm
Location: Boston, USA/Jackson Hole, USA

Re: Live Stack with Flat Frame Bug?

Post by GaryS »

Hi Chris:

I've used Darks without Flats and it seems fine. Will Flats work without a Dark being applied? I hear differing thoughts on this.
One more....do you capture and apply Darks when using a mono camera? (I have the ASI 178 MM.)

Cheers
Gary
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turfpit
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Re: Live Stack with Flat Frame Bug?

Post by turfpit »

Gary
do you capture and apply Darks when using a mono camera
Have a look at viewtopic.php?f=18&t=1809. The info there applies to both colour and mono cameras. I will add some info for mono cameras into that thread.
Will Flats work without a Dark being applied
Sort of. With a cooled camera and shorter exposures the results may be acceptable. See the link above for what you will not be removing.
I hear differing thoughts on this
Part of the problems with forums. I have found that advice supported by images is the most helpful. Don't be afraid to try things yourself and evaluate the results. You could get on www.astrobin.com, find some images you like and see if darks are used.

Dave
GaryS
Posts: 47
Joined: Sun Mar 31, 2019 5:18 pm
Location: Boston, USA/Jackson Hole, USA

Re: Live Stack with Flat Frame Bug?

Post by GaryS »

Thank you Dave!

I'll get into the linked topic and see what's up.
BTW, I agree on your experimentation point. Being 1 year into all this and still feeling there's still so much to learn, I sometimes when I haven't had time to test something, I try to short circuit the process and ask others.

Thanks for your help.
Gary
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turfpit
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Re: Live Stack with Flat Frame Bug?

Post by turfpit »

3 years in and still feeling there is so much to learn … :lol:
goldtr8
Posts: 10
Joined: Sun Jul 22, 2018 8:22 pm

Re: Live Stack with Flat Frame Bug?

Post by goldtr8 »

So I am suddenly having the same issues with Flats.

What is the final verdict using a ZWO294 camera.

From my reading here is what I think I should be doing

Brightness set to zero
50 50 for the color sliders
Gain between 120 and 300
250ms exposure time is the target
Mono or Color this I am not sure about, but I am guessing color
Bias or no bias frames, not sure about this one either.
I never move the image train its set up in a ROR observatory.

If I look at FITS Liberator to check the ADU levels are their any obvious things to be aware of that can help qualify if the Flats will promote the outer edge being overly brightened. I have some thoughts on this but maybe someone already has a quality check sorted out.


Regarding Darks I understand the need to make sure these match the actual data frames. Biggest problem with these is the amp glow as I don't have a cooled camera so I don't have a clean library, but this I understand so I know how to address it.

Thx
Don
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