NGC 7023, Iris Nebula, 3 Jun 2014 (David Dearden)

NGC 7023, Iris Nebula, 3 Jun 2014

It was quite gusty when this was imaged but also quite clear. I had some difficulty focusing because the scope was blowing around so much. Seeing was relatively poor too. I used the PicGoto starting from alpha Ceph and easily found the Iris Nebula. I ran the chiller at 2.5 A; starting temperature was 8.5 °C on the CCD. It was a warm night, so I consider that pretty good. I used the low pass Dec guiding algorithm instead of "resist switching," which is what I usually use. I can't tell whether it really helped (because I think the wind was the biggest factor), but things did seem to settle down after I started using it (and went to bed). Overall, I was happy with the number of subs I was able to keep and feel this is a much better image than my one and only "picture of the day" image from two years ago. I may want to try processing this without the "Life" procedure because I think "Life" may hurt some of the contrast in the central nebula.

The revised version is without the "Life" step, with 1 step of "Magic" star shrinking, and a little more stretching with CS6 Levels.

Date: 3 Jun 2014

Subject: NGC 7023, Iris Nebula

Scope: AT8IN + HPS Coma Corrector

Filter: None

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.2.2 (Win 7 ASCOM)

Camera: DSI IIc chiller at 2.50 A, 8.5-3.5 °C

Acquisition: Nebulosity 3.2.0, no dither

Exposure: 46x300 s

Stacking: Neb 3, bad pixel map, bias included, normalize first, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3.5.279 Crop; Wipe:Color & brightness; Develop 87.49%; Color:Scientific, 250% sat.; HDR:Reveal core; Deconvolute auto mask 2.2 pix; Life:Heavy; Track RNC 17.40%. CS6 Astronomy Tools increase star color; Healing brush; Deep space noise reduction (twice); Levels; Astro Frame.

Original
Final
B

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Status	Basic failed
Started	...
Astrometry.net job	4187087
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