which ISO for DSO?

[alacant]

Hi everyone

I just switched from ISO800 on a Nikon D40 to a Canon 1200D. I'm at a loss as to which ISO to use on the Canon. Does anyone have any favourite ISO setting for Canon? TIA

[VSOP]

It really depends on which DSO you wish to photograph along with many other factors. If you have good tracking and can take longer exposures, you can run a pretty low ISO and keep the noise to a minimum. I shot Orion Nebula a few days ago for 30 seconds at ISO 800. For smaller DSO at much higher relative magnitude, that would result in nothing captured.

[StargeezerTim]

I routinely use iso 1600 on my 100d and it seems to work fine, though most here don'the recommend going above 800.

Try a target with different iso's and make a comparison...

[wxsatuser]

Faint stuff ISO 1600 brighter stuff 800, should do it.
 

[alacant]

OK, thanks. One more newbie bit: if I change ISO, I also redo bias, flat and dark?

[wxsatuser]

Darks and bias some iso as lights, flats normally a low iso.

[dph1nm]

2 hours ago, wxsatuser said:

Darks and bias some iso as lights, flats normally a low iso.

As the bias has to be subtracted from the flats I would use the same ISO for both flats and bias.

NigelM

[dph1nm]

22 hours ago, alacant said:

I just switched from ISO800 on a Nikon D40 to a Canon 1200D. I'm at a loss as to which ISO to use on the Canon. Does anyone have any favourite ISO setting for Canon? TIA

Sensorgen suggests you want to be at ISO1600 or above for the lowest  read noise, but I think you are well above unity gain there so wasting dynamic range. So it depends if your subs are long enough to overcome read noise. If they are I would lower the ISO. The honest answer is it probably doesn't really matter very much!

NigelM

[Dbswales]

Being a total nembie to both cameras and AP, I was totally lost but found that iso 800 was what worked best for me with my modded 600D. I also keep everything at the same settings otherwise DSS and PI get 'grouchy'.