[DIYman (Doug)]

Talking to a astro friend about the best sequence to use when shooting LRGB and we came up with the following process which may interest others.



First, the obvious needs to be mentioned, the best time to image an object is when it is crossing the meridian so that's when the Lum should be taken.



Anyway, here what we are going to be doing where possible (note that last word).



We tend to use 90 sec exposures to avoid over exposed stars and dither for all exposures (I know, I know) and allow 10 secs for the mount to settle after each dither. Adjust the settings to suite your own workflow but I will use ours as an example.



Start exposing when the object is 90 minutes from the meridian.

Red 9 exp

Green 9

Blue 9
Lum 54
Blue 9

Green 9
Red 9


The sequence ends when the object is 90 minutes past the meridian and the process starts for the next next object. (Repeat on another night if more exposures are needed.)



We chose this sequence of the filters as we believe the red filter should be used first as it will be affected least by light passing through the thicker part of the atmosphere. Green follows and then blue which is affected the most by atmospheric scatter. The Lum exposure is the most important and is to be used when the object crosses the meridian.


We realize that flexibility is needed here, such as when the target object is not situated at the optimum altitude or when an object is imaged over more than one nights etc etc.



Anyway, I thought it is an interesting idea and wrote it up while having a beer. Your criticisms and comments please. Cheers.