Good job jmacon
I prefer this version (better colors and details) to your CCD version.
I saw 3200 ISO 180s in Astrobin… I don’t know the dynamic of the 6D but with my 600D and my skies, 60" at ISO 3200 are more than enough to completely burn the image ! Your skies must be rather good.
Do you use AF routine ?
Thanks Pulsar59. I have revised the listing to show
120 sec ISO 3200 x 18, 240 sec ISO 6400 x 21 all integrated together.
I was experimenting with different combinations. The only target I have seriously blown out at these ISOs is my M42 which I ended up doing ISO 800 for 120 sec, and still the core is a bit blown out.
My NGC7000 which is on Astrobin was taken at 300 sec ISO 25600 and came out ok. It was the first light from the new obs. At that time I thought the higher ISOs would give me better SNR, but I found this article http://www.clarkvision.com/articles/iso/
which seems to be very authoritative, and says ISO 1600 is optimum for my 6D, which is what I have been using lately.
For this image I only used AF at the start of the session so these might not have optimum focus. Now I am using temp compensation since from the logs I have derived a good temp formula which is working quite well. Occacsionally SGP give me a bad focus pos so for a hour all my images were badly out of focus, so I turned it off. I think the focus routine has a hard time finding real stars in star poor regions.