RGB L sub times for a ASI 1600mm pro

[vlaiv]

36 minutes ago, tooth_dr said:

This has puzzled me. Why would this be any different to imaging in an area of low light pollution with a luminance filter?  

In principle it is not, however good NB filter will cut LP at a rate of about x50-100 - for example 3nm NB filter will eliminate 99% of LP from 300nm range (400-700nm is full spectrum).

x100 less light is 5 magnitudes. Natural sky brightness is about mag22, so yes, good NB filters make difference as moving from bright city center to best skies available - from mag17-18 to mag22 (4-5mag difference, or about x50-100 less light).

Moving from mag19 skies to mag21 skies is only 2 mag difference and that is about 6-7 less LP light - effect of UHC filter maybe?

[jimjam11]

The cn thread is a superb resource for the asi1600. I use same length subs but vary the gain between l and rgb. I normally use gain 0 for l and gain 76 for rgb. 

@ f4.5 that leads me to 60s exposures.

@ f5.9 I use 120s.

@ f9 I use 300s.

Something else to consider is your efficiency; lots of short subs with a long interframe delay can massively cut into your acquisition efficiency. If you use a slow computer with usb2 it could easily be >10s per frame which is a huge percentage loss. Try to get this delay <2s per frame.