Darks for LRGB

[kirkster501]

Hi all,

Does one need to collect darks for all data channels? Luminance included? I know many say no need for darks with electronically clean sensors like Sony chipsets....? But lets say I do want to use darks, do I need darks for all channels or just one set? Surely the latter since the scope is covered. But just sanity checking....!

Should flats be captured for lumimnance channel as well and RGB? What level should the flats be? 20000 ADU I have seen discussed?

Thanks, Steve

[johnrt]

flats for each and every channel, just 1 set of darks needed, provided that is you captured each channel at the same temp. Aim for about 23k on your flats. Think of flats as imaging the optical path of your scope and filters, if the filter, focus or orientation changes, the optical path is different and therefore you need a fresh flat.

[Stephen]

Darks can be reused for all channels, but you really don't need them on the 460

Flat are unique to each channel and I find 20K is optimum for the 460

[ollypenrice]

Flats are theoretically needed for each channel but if you have clean filters in a sealed (ie electric) filterwheel then it probably will be a tedious waste of time to take them. I no longer bother and neither do many well known imagers with whom I've collaborated. The thing is to try it. If you find you don't need them for all channels then give yourself a break! When I stopped taking multiple channel flats I confessed to a much-published friend and he just said he went over to Lum flats only several years ago.

Around 23K or a little lower works best for me. Take a lot and use a master bias to calibrate them. This is most important.

Be aware that darks have a dark side! They can damage an image as well as correct defects so, if you don't need them, don't use them. What does work very well in Astro Art 5 is a bad pixel map (for which AA has a box on the stacking page) and a master bias used as a dark.

Not all will agree with everything I've said here but I've come to this routine after trying many others and it works for me.

Olly

PS, A perfectionist would advise you to take darks and bias off the scope using the metal screw on cap that Atik supply. This is not only totally light proof but also more resistant, I'm told, to Gamma ray strikes which can appear on darks and bias.

[Daniel-K]

Gamma ray strike thats pretty cool good info im looking at a 314 so this will help me when it comes tO LRGB

[johnrt]

I no longer bother and neither do many well known imagers with whom I've collaborated. The thing is to try it. If you find you don't need them for all channels then give yourself a break! When I stopped taking multiple channel flats I confessed to a much-published friend and he just said he went over to Lum flats only several years ago.

Sacrebleu!!

[Russe]

Which programme do you get the 23K from?

Astro Art?

[ollypenrice]

Which programme do you get the 23K from?

Astro Art?

I use Artemis Capture and it gives you a black and a white point. Just read the values for the white point. Nice and easy.

Olly

[ian_bird]

Flats are theoretically needed for each channel but if you have clean filters in a sealed (ie electric) filterwheel then it probably will be a tedious waste of time to take them. I no longer bother and neither do many well known imagers with whom I've collaborated. The thing is to try it. If you find you don't need them for all channels then give yourself a break! When I stopped taking multiple channel flats I confessed to a much-published friend and he just said he went over to Lum flats only several years ago.

Hi Olly

Am I correct in thinking you only apply the Lum flats to the Lum subs? And leave the RGB subs without flats?

Cheers

Ian

[ollypenrice]

Hi Olly

Am I correct in thinking you only apply the Lum flats to the Lum subs? And leave the RGB subs without flats?

Cheers

Ian

Hi Ian.

No, I now use the lum flats on all images. I found the various flats were effectively identical and since taking them is amongst the least interesting things that I do in life (even at my age!) I was glad to find I could cut the workload by five. I'd say try it. If it doesn't work go back to multiple flats. If it does work, well... take a break.

Olly

[davew]

Hi Ian.

No, I now use the lum flats on all images. I found the various flats were effectively identical and since taking them is amongst the least interesting things that I do in life (even at my age!) I was glad to find I could cut the workload by five. I'd say try it. If it doesn't work go back to multiple flats. If it does work, well... take a break.

Olly

That's a bit of information that should be more widely known. If it works ok, and I can't see why it won't, then it gets rid of one more obstacle to RGB management each night.

Nice one,

Dave.