Helix - ASI1600 long exposre testing

[Gvarouha]

G'day all,

Have been doing some testing with my new asi1600 and esprit 80ed to see how long exposures turn out.

Hi res version:
http://www.astrobin.com/263180/0/

This is a total of 39 x narrowband subs @ 900sec. I'm impressed with the results and how noise free the image was (I actually had to add some comfort noise to the background).

I think with this camera more shorter exposures may be the way to go, as I also did a couple of 300sec subs and couldn't see too much drop in signal.

Cheers guys.

[Atmos]

Really nice George! The detail is very good :)
In the centre of the Helix there is some orange speckle, any idea what's causing that?
Love the colour you've got too.

[glend]

George, i use 300" at Unity Gain (139) setting for most of my narrowband with the ASI1600. Fast narrowband can be done effectively, on some targets, at a Gain of 200 (offset 28), using 90" subs, but it will introduce issues with clipping and the thin data requires care in processing to not over stretch. Obviously these sub duration settings depend on the speed of your scope ( in my case f5.3).

[RickS]

Nice result, George.

[willik]

Nice shot of Helix but there is specks in the centre of the eye it could be some noice or dust strange but still very nice image.

[Gvarouha]

Thanks for the comments, Those specs were causing me all sorts of grief. I believe I may have over sharpened or maybe from over stretching the SII channel, not sure why they are orange.

Glen, I agree 300sec does appear to be a sweet spot for narrowband as I am shooting at a similar f ratio (f5).