California Nebula

This is my first image using my new Atik 383L+ mono. Taken in early March with 9 x 900s with the Baader 7nm Ha filter and processed in PixInsight. I’m still learning process techniques with PI, Harry’s tutorials gave me a great start (thanks Harry!) and the new PI resources website is helping.
I had difficulty with Elbrus plate solving at first for this target as the FOV is greater than 10deg. Then Ken and Jared came to my rescue by working to revise the integration with Elbrus and automatically switching to the 10deg databases.
Thanks for looking.

Thanks for sharing Barry. Glad to hear that Elbrus widefield is working for you.

How do you find the Atik CCD works out?
Also do you need longer exposures with the Ha filter?


Hi Roger
In comparison to my 460EX it is noisier and more care is required taking flats due to its shutter operation. Otherwise, it gives a great FOV and the arcsec/pixel resolution suits and complements the SW 80ED and my WO FLT 132. For flats, I’ve found that my EL panel needs 4 sheets of paper for Lum and Blue, and 3 sheets for Red and Green; this gives about 8 seconds or so for each sub at 22,000 ADUs +/- 500, more than enough sub length that the shutter doesn’t show. Using PixInsight’s Cosmetic Correction also helps in calibrating the frames I’ve found and there is more vignetting than the 460EX as you’d expect: DBE and ABE deal with it very effectively. Both Atik ccds are excellent photon hoovers and the recent price reductions make them tempting . . .
For Ha, I use a minimum of 600s subs, often 900s and when there is no moon about I will use 1200s or 1800s (all at 1x1 binning). I find that there are gradients when the moon is up if I expose for longer than 900s. A narrower band filter, e.g. Astrodon, I’m sure will fare better. I use 45s exposures for each NB filter in the autofocus routine at 2x2 binning and this gives a crisp focus; with 9 focus points AF does take an age it seems, but focus is everything.