Trunk in Ha

[Andyb90]

21 hours ago, Rodd said:

If that's true--what would be the advantage of the 0 gain?  Both 0 and 139 seem to generate identical stacks using eth same number of subs with the same exposure times

I think zero gain could be useful for L. I tried 2 minute exposures at unity a while back, but the star clipping was more than I'd like. I'm going to try same exposure at zero gain. I've seen some good results with this approach. I'll try for around 100 subs.

Andy.

[Rodd]

51 minutes ago, Andyb90 said:

I think zero gain could be useful for L. I tried 2 minute exposures at unity a while back, but the star clipping was more than I'd like. I'm going to try same exposure at zero gain. I've seen some good results with this approach. I'll try for around 100 subs.

Andy.

Maybe it depends on the sky, as well as the focal ratio--I have been using unity and 2min subs for LRGB channels, at F7.7.  The stars have color (as much as they ever did using KAF 8300 at least).  If I throw a reducer so its F5.4, maybe the gain and exposure times need to be rethought.

Rodd

[Allinthehead]

19 hours ago, Rodd said:

Maybe it depends on the sky, as well as the focal ratio--I have been using unity and 2min subs for LRGB channels, at F7.7.  The stars have color (as much as they ever did using KAF 8300 at least).  If I throw a reducer so its F5.4, maybe the gain and exposure times need to be rethought.

Rodd

I would say at that f ratio with an L filter 0 gain would be good. 

[Rodd]

15 minutes ago, Allinthehead said:

I would say at that f ratio with an L filter 0 gain would be good. 

I was thinking that at F7.7 a higher gain would be better--goes to show I have no feel for gain at all! My goal is to find a gain that works and change the exposure time while leaving the gain set....that way I can use 1 set of  flats.  So far I have not run into a problem with unity gain and 2 min broadband and 5min Ha subs.  Then again I have not tried 0 gain.  But judging from your example, I don't see much difference between unity and 0 in the integrated stacks (in fact I see no difference with the jpeg).

Unfortunately, the amount of clear sky time I get is so minimal that experimenting is not something I want to do.  

[Allinthehead]

Sorry Rodd i meant at f5.4