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INDI Library v1.9.5 Released (08 Mar 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

Dark Flats

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Dark Flats was created by Brian

In the Ekos capture tab there is a dropdown with selections of lights, darks, flats, and bias frames. I forego bias frames and use dark flats instead. Most stacking software now has provision for using dark flats. Is it a possibility to have dark flats added to Ekos?
-Brian

NanoPC-T4 - Armbian focal
iOptron CEM25P mount
Photoline 80mm triplet refractor
ZWO ASI294MC Pro Imaging camera
ZWO ASI290MM mini Guide camera
ZWO ASI EAF focuser

2 years 1 week ago #53423

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Replied by Wouter van Reeven on topic Dark Flats

Dark flats are simply darks with an exposure time equal to the exposure time of your flats. So for processing it suffices to create darks with, say, 2.0 sec exposure time and use those. The file name can easily be modified and Ekos allows for adding the exposure time to the file name so you ca distinguish them from the "genuine" darks. Both APP and PI accept dark flats created this way.


HTH, Wouter
Wouter van Reeven

ASI6200MM and 7 slot 2" filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and 5 slot 1.25" filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
The following user(s) said Thank You: Craig
2 years 1 week ago #53431

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Replied by Brian on topic Dark Flats

Maybe I should have said "flat darks". ASTAP calls them flat darks, DSS calls them dark flats. I'm not sure we are on the same page. I take my flats then put the cover on the scope and take my flat darks, all settings the same as my flats, they are just dark. Both flat and flat dark files go into the same directory and I separate them out later, not a big deal, I've been doing it that way for a long time but it would be more polished to just have a flat dark option along with lights, darks, bias and flats in the Ekos capture tab.
-Brian

NanoPC-T4 - Armbian focal
iOptron CEM25P mount
Photoline 80mm triplet refractor
ZWO ASI294MC Pro Imaging camera
ZWO ASI290MM mini Guide camera
ZWO ASI EAF focuser

2 years 1 week ago #53436

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Replied by Paul on topic Dark Flats

Brain,
What you are asking is not clear - to me anyway.
Ekos is about collecting the data not processing it.
Are you asking that a master dark is automatically subtracted from each flat before being saved?
Paul
Losmandy G11 with Gemini 2 controller
QSI 583/683 monochrome camera with filter wheel
Starlight Xpress Lodestar X2 guide camera
Microtouch Focuser controlled using Arduino UNO emulating Feathertouch controller
Raspberry Pi 2GB with Raspberry Pi OS 32bit
2 years 1 week ago #53463

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Replied by han on topic Dark Flats

You have

Master bedroom
Master dark
vice president

but headmaster, the head teacher


so a dark used for calibration of a flat would be:

Flat dark

It will have the same exposure length as a flat.

I bias is a frame with exposure of zero seconds or very close to zero=0.001 seconds.

Also found this discussion about to proper naming:

www.cloudynights.com/topic/594366-does-a...eplace-a-bias-frame/

I'm open for suggestions.

Han
2 years 1 week ago #53469

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Replied by Richard Beck on topic Dark Flats

For what it's worth, I use a folder for flats and collect the darks for flats as a subfolder of the flats folder. I choose to spell it out here to distinguish them from darks for lights, which is generally just called darks.

In any case, just keep track of where you put your darks. After I have masters, I have all the exposure lengths in a single folder for a date, gain and temperature. If I need to do new flats, I calibrate them with the appropriate master dark. In my case, I have one narrowband flat exposure equal to my shortest light exposure. I then don't have to shoot different flats for that filter.
Losmandy G11G, ZWO OAG, Celestron OAG, ASI 120MM mini guide camera, SV 80ST, TPO RC8, ASI 1600MM Pro, ASI 294MM Pro, ASI filters and filter wheel
2 years 6 days ago #53485

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Replied by jiberjaber on topic Dark Flats

This would be a useful feature if combined with the calibrate facility. If I shoot flats with a set ADU requirement of say 30,000 then I get different exposure rates for each filter ranging from 0.3s upwards, problem is they are not 0.3s but in fact
L 0.313412s
R 0.683737s
G 1.582250s
B 0.790333s

So this becomes a bit of a pain to then make sure the right exposure is in the right place for the dark to be taken - be good to perhaps store this with say the focus value ? (last flat dark exposure per filter?)
1 year 11 months ago #54337

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Replied by ALESSANDRO PENSATO on topic Dark Flats

I also think that could be a great function have a DARKFLAT option and an autamatin plan created with the same values of exposure of the flats for each filter. Acutally I have to make a DARK plan copiyng the exposure times from the flat plan.
1 year 11 months ago #55585

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Replied by ALESSANDRO PENSATO on topic Dark Flats

Any news?
1 year 10 months ago #56440

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Replied by ALESSANDRO PENSATO on topic Dark Flats

Any news?
The following user(s) said Thank You: Scott Denning
1 year 8 months ago #58788

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Replied by Roland Roberts on topic Dark Flats

I'll second this. I've gotten used to having dark flats as an option in other DSLR control programs and, from what I can tell, the recommendation is to use flat darks/dark flats for calibrating your flats for any CMOS based sensor rather than bias frames and scaling which would include my ZWO/ASI cameras.

For all practical purposes, I'm really just looking for a label on the files; near as I can tell, there is no standardized FITS imagetyp keyword for this, so it's really a convenience for me to organize my files correctly.
1 year 6 months ago #61760

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Replied by Wouter van Reeven on topic Dark Flats

In that case I repeat my comment at the top of this thread: simply create darks with the same exposure time as your flats and then rename the folder from Dark to DarkFlat and rename the files in that directory in a similar way. I agree that it would be much more convenient to have the possibility to select a DarkFlat option in Ekos but until then this is a perfectly viable option. It is possible to write a bash script to do the renaming automagically if you want though it may be tricky if you have both Darks and DarkFlats in the same directory.
Wouter van Reeven

ASI6200MM and 7 slot 2" filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and 5 slot 1.25" filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
The following user(s) said Thank You: Richard Beck
1 year 6 months ago #61764

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