Add RGB stars to a NB image: how much data?

[barbulo]

According to your experience, how much time do I have to dedicate to RGB filters to add a decent star layer to a NB image? There are a couple of targets that are about to disappear from my fov and I’d like to squeeze them a bit more. 
Thanks in advance. 

[Richard_]

I'd like to know this too, so I'm following this thread. 

[wimvb]

Not much, really. Stars are bright, and  you won’t be using the star background. Depending on gear, conditions and expectations, only few subs per colour.

[barbulo]

Thank you very much. I’m afraid the processing is going to be the difficult part. 

[wimvb]

23 minutes ago, barbulo said:

Thank you very much. I’m afraid the processing is going to be the difficult part. 

Starnet v2 is your help. Extract the stars from the RGB image, and put them into the starless NB image.

 

[barbulo]

18 minutes ago, wimvb said:

and put them into the starless NB image

No need to tweak them before? I’ve processed nebulae separately but never stars. Yet to learn!

[wimvb]

1 hour ago, barbulo said:

No need to tweak them before? I’ve processed nebulae separately but never stars. Yet to learn!

Just stretch them gently. Avoid bloating them too much. Stars from refractors are easier than stars with spikes.

[pharscape]

If its just stars that need RGB I've gone as short as 15mins per colour but I normally do 30mins per just so the spikes can be clean on bright stars. If you are going to have spikes, make them nice ones. Most of my imaging is a F4.8. I've not looked at the minimum I can get away with.

[barbulo]

All right. 30min per channel sounds "affordable". Will 30s-60s subs do the job?

[pharscape]

17 minutes ago, barbulo said:

All right. 30min per channel sounds "affordable". Will 30s-60s subs do the job?

With my setup I find 30sec subs seem to always work with low chance of burnt out stars.