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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Dark Flats Option in Capture Module - Using Dark Filter

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Hello

I'm the proud owner of a dark filter, which I use for doing dark flats instead of Bias frames. My understanding (crash helmet on here!) is that Bias frames are more useful for CCD cameras whereas Dark Flats are a good way to go for CMOS. Irrespective of the debate as to which is best, Dark Flats are a very common and successful calibration method for me.

I have a dark filter on my EFW, and it works great for this purpose, because I have to do a run of dark flats every session to match my flats. What does not work is treating it as a normal filter, selecting it and doing a run of "Lights" in the Capture Module, because I have an autofocus setup, and the Capture Module always tries to do a focus run which fails and then aborts the sequence. This is what happens even when I deselect the "Autofocus on Filter Change" on the EFW dropdown box in Capture module.

I have to manually select the dark filter using INDI --> EFW --> Controls --> Select Filter Slot --> Set. Then I do a run of Darks in the Capture Module; when it tells me to cover the telescope I just hit Continue, and I do the capture.

Could I please REQUEST:-
1. An additional selection on the Light/Dark/Bias/Flat dropdown in the Capture module which gives the option of using a dark filter or manually covering the scope? It would save the files in a folder separate to everything else for clarity, but also circumvent the dead-end autofocus issue which aborts the sequence.
2. A more robust method to circumvent the autofocus routine for a given filter. The dropdown box for the EFW in the Capture Module seems to have no influence.

Either of the above would make the taking of Darks and Dark Flats using a dark filter far more practicable.

Cheers
Mark
Last edit: 2 years 11 months ago by Mark Sandford.
2 years 11 months ago #70491

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IIRC, this was discussed several times in the forum. Please remind me why you can't take regular dark frames with the same exposure/ISO of the flat frames? or is it that you want the flat-dark frames to have their exposures adjusted automatically to match the flats?
2 years 11 months ago #70511

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After that the flat procedure is completed you can edit it by change the Type from FLAT to DARK, and if you prefer you can also add a prefix like FILTER_Darkflat. With this you can quickly take darks without have to re-enter the exposure value for each filter
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2 years 11 months ago #70515

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wrong topic, please delete
Last edit: 2 years 11 months ago by ALESSANDRO PENSATO.
2 years 11 months ago #70532

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Hello Jasem, this really applies to any dark frames using a dark filter.

To summarise: when EKOS asks us to "cover the telescope" for the dark frames, could we please have an option on that info screen to select the dark filter as a means of doing this? We already have a question which asks if the camera has a shutter; adjusting that screen to allow for a dark filter option would be perfect.

The issue as it stands is the autofocus routine in the Capture module. I have my dark filter loaded in my filter wheel, and if I select it as I would for any other filter and ask for a run of "Light" frames, the autofocus kicks in, even if I have deselected that filter for autofocus in the filter wheel drop-down box at the top of the Capture module. The autofocus routine then fails of course because there's nothing for it to see, and the sequence is aborted.

Going through the Dark frames selection in Capture, there is the command from EKOS to cover the telescope, which is fine, but there is no option to select a dark filter, I have to go through INDI --> EFW --> Filter Wheel --> (select filter slot number), then run a series of Dark frames. No big drama, but it would be nice to do this a bit more conveniently - a button on the "Please cover telescope" popup would be ideal.

A Dark Flats selection in the dropdown box would be even better. We could run them as a separate command line in Capture, select cover telescope or dark filter, then and have the frames filed in a separate folder like we can do now with Bias/Light/Dark/Flats etc.

Hope that explains it
Last edit: 2 years 11 months ago by Mark Sandford.
2 years 11 months ago #70536

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Ok, so here is how I think about it. You want to capture flats, and then after that the dark for these flats. since the time per flat image can be different due to ADU requirements (if this was sent), the duration of the flats is not necessarily known in advanced. Therefore, it would be more convenient if Ekos would create darks with the same duration as the flats before.

Furthermore, you don't want to get notified about covering the scope, and instead want to use a Dark Filter. This is similar to the calibration settings now, but instead of using a cover for the whole scope, you just want to cover the sensor by going to a blocking filter. I think this can be perhaps realized:

1. Add "Blocking Filter spinbox" to the calibration settings as an option for "Flat Source"?
2. Add checkbox to automatically generate dark flats whenever flats are added to the sequence?

Ekos would then generate the dark flats using the "blocking filter" option if such exists. The exposure would be set after flats exposures are settled.

Ok, did I miss anything?
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2 years 10 months ago #70840

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Hello Jasem, yep that sounds right to me!
2 years 10 months ago #70866

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