Next QHY9 CCD Question : How do you take flats ?

[Catanonia]

I am used to setting the DSLR to apeture mode on ISO 800 and using a laptop / notepad screen as a source.

The DSLR would auto set the shutter speed and I could gather lights ?

How do I do a similar thing with QHY9 CCD and MaximDL 5 ?

I can see the sequence part (use that already for the LRGB) and how to set a flat, but how does it know how long to expose for or do I have to guess an exposure time in seconds ?

Any help would be nice, I suppose applies to any CCD and not just QHY9

Thanks

[moocher]

OK,

You need to know the full well depth of the ccd. Then in Maxim change the info window to show area then expose say for 2 secs and look at the highest figure it gives you in the box. You want approx 2 thirds of the well depth.

The 285 chip has a full well capacity of approx 45,000 so i aim for about 26,000.

If you get stuck PM me....its all fun isn`t it!!!

Alan:D

[Catanonia]

Ok which parts, not too sure on well depth, have an idea on it.

Is the depth the Max - Min = Depth and I want 2/3rds ??

Not 100% sure

Ta

[moocher]

Forgot to mention to get the figure to change you need to change the exposure value up or down until you get to the approx value...

Alan:)

[Catanonia]

Forgot to mention to get the figure to change you need to change the exposure value up or down until you get to the approx value...

Alan:)

Been reading a bit, yes they say with the QHY9 slow shutter, to avoid artifacts you need between 5 - 10 seconds and dim light.

Still not sure on how to calculate the well depth with these figures. Any Guidance.

[Paxo]

Do a series of exposures until you get an average (as shown on the clip above) reads 26,000 (or as close as you can get). The well depth of your camera should be available from the manufacturer. IMO stick to about 24,000 to 26,000 as average you should get useable flats.

Steve

[moocher]

Its been ages since i`ve done this, i think its the max....yeh thats it you don`t want to "saturate" the pixels just 2 thirds of the well depth...HTH

Alan:)

[moocher]

My mistake, sorry. Like i said its been ages since i`ve done anything!!!!

Alan:o