Ideas for exposure time with Lp filter

[spiezzy]

hi to all now I have sorted out my colour issue with my set up (thanks Dunk and Colin )
I am going to give M27 another go tonight but was just wondering with the Pro Star LP filter what would be a good exposure time for my subs I was planing on 300 sec would that get enough data or should I go higher
equipment is GSO 10" F4 truss newt astrograph , Sbig 8300c (colour) with a Baader MPCC fitted and a Pro Star LP filter on a Losmandy G11
many thanks in advance
cheers Pete

[billdan (Bill)]

Pete,

Its the total integration time that counts, the exposure time of each sub doesn't really matter as long as each sub isn't dominated by sky glow. That used to be the criteria for setting sub times, keep increasing exposure until sky glow starts to brighten.

More stacked subs also means better signal to noise ratio, so a 30x300sec stack will look cleaner (less noise) than a 15x600sec stack.

Be aware shooting OSC behind a LP Filter may create issues with white balance later, as the yellow content of the colour spectrum is stripped out.

Cheers
Bill

[spiezzy]

hi there Bill
thanks for the reply and your help I understand about the more subs the better SNR is , would you recommend not using the LP filter with the OSC camera what happens when the yellow is stripped out of the image .
cheers Pete

[billdan (Bill)]

Pete,

I just remember on the Startools forum how someone couldn't get the colours of a galaxy looking correct (too much magenta) and the LP Filter was the culprit.
Have a go and you decide whether it has any effect.
I don't have one so I have never tried it.

Bill