Best way to take Flats with DSLR in KStars/EKOS

[Ouroboros]

What is the best way to take flats when using a DSLR in KStars? 

I expected I'd be able to set camera to aperture priority and to bang off some flats as I normally do when using Backyard EOS. That doesn't seem to be possible in EKOS. Or is it? 

Any suggestions? 

PS in the end last night I disconnected the DSLR from the MacBook and took the flats manually at the camera. 

[alacant]

Hi. You could set aperture priority in the indi panel or, easier, set the camera to Av pointed at your light source, depress the shutter to get the exposure, set it back to M then fire off the flat frames in EKOS using the shutter speed you just found.

Just two of many methods...

Cheers and HTH.

[Ouroboros]

54 minutes ago, alacant said:

Hi. You could set aperture priority in the indi panel or, easier, set the camera to Av pointed at your light source, depress the shutter to get the exposure, set it back to M then fire off the flat frames in EKOS using the shutter speed you just found.

Just two of many methods...

Cheers and HTH.

I thought of doing it the second way you suggest.  But I'd have thought I would have to disconnect the camera from EKOS to do that .... and then reconnect*.  Do I not? 

As for your first suggestion, wouldn't it actually be easier to set to aperture priority in the INDI panel? 

I'd try it now but I'm not near my MacBook and camera. 

[alacant]

11 hours ago, Ouroboros said:

not near my MacBook

Try both and see which is best for you? But no, no need to disconnect the camera. Just flip the dial around to Av and leave the indi control panel on M. Just flip back to M when you have the exposure time.

If you want  a complicated  an alternative method, you could use ekos' flat calibration module:

HTH and do let us know what you decide.

 

[feilimb]

The 'flat calibration module' in Ekos has been buggy as hell for me and I would not recommend it.  It often used to come back with a calculated ADU value that it reported as eg. '5000.9999999999999999' (lots of 9's after decimal point) and after that stage it would never recover.

Also: note that if you take flats manually in AV mode, note that they will be CR2 files on the SD card - if you have captured lights and darks using Ekos as FITS files then some stackers like Deep Sky Stacker will not allow you to stack a mixture of file types (ie. it will not allow some frames in FITS and other in CR2), so as suggested above it is probably best to use AV mode just to find out exposure length, and then set that manually in Ekos to capture the actual flats.

[Ouroboros]

On 23 September 2019 at 12:32, feilimb said:

The 'flat calibration module' in Ekos has been buggy as hell for me and I would not recommend it.  It often used to come back with a calculated ADU value that it reported as eg. '5000.9999999999999999' (lots of 9's after decimal point) and after that stage it would never recover.

Also: note that if you take flats manually in AV mode, note that they will be CR2 files on the SD card - if you have captured lights and darks using Ekos as FITS files then some stackers like Deep Sky Stacker will not allow you to stack a mixture of file types (ie. it will not allow some frames in FITS and other in CR2), so as suggested above it is probably best to use AV mode just to find out exposure length, and then set that manually in Ekos to capture the actual flats.

Thanks for that.  Yes, I hadn't thought of the FITS aspect, but as it happens I'd set it to download 'native' so I'm getting all files as CR2. 

I've had a quick go at getting  flats by as you say to use AV mode to get exposure. I ran into two problems. Firstly, pressing the shutter in AV mode locks up the camera or KStars requiring everything to be restarted. Secondly, EKOS doesn't seem to give me access to all the available shutter speeds on my 450D.  As I say, I only had a quick go at it so I need to play some more to get a better idea of things. 

[alacant]

Hi. JTOL...

Remove the SD card.

Take both light and flat frames as fits files and store on the client.

Don't forget the indi control panel:

options > force bulb > off

press the shutter partially in Av then back to M. Use usb2 sockets and cables.

Still no go? How about the fits viewer histogram tool? Get it central and shoot.

HTH

 

[Ouroboros]

OK I think I (kind of) get it now having played with it. Does this sound reasonable?

I'm using the calibration module. So I set ADU to 5500 (tolerance 1000) which is roughly one third of  2^14.  Is that reasonable?

I have discovered that the ADU calculation only works when files are saved as FITS.

So, starting off at an exposure in my case of 0.25s KStars keeps taking images  until it gets the exposure to a level near 5500.  It then starts saving the number of images set in the counts box.