Needed RGB for just Stars

[Earl]

Im working on a Californian Nebula image.

First of all its goign to be a 2 pane mosaic.

Im planning on 1.5hours per pane (6 x 900s) Ha one half is done.

i then want to get the stars in RGB what sort of total exposure will i need for this? im not fussed about the nebulosity having detailed RGB as thts the Ha's job,

[Zakalwe]

I used 40 seconds (6 off, in each colour channel) to add star colour to my NGC6888. They're not perfect, but not too bad either.

NGC6888-Bicolour with RGB Star Colour

Just suck it and see as each rig will be different.

[Earl]

thats promising, ill have a dabble then