I’ve had a combination of cloudy weather and being busy at work that has prevented much imaging for the last little while. I did manage to squeeze in a little integration on the γ Cassiopeiae “Ghost” nebula. I had intended to do SHO, but it looks like it will be a while before I can get any more data and I suspect SII won’t add much because this object appears to shine mostly in Hα so I decided to see how HO would look. The OIII for the nebula itself is very weak. I struggled a bit with my focuser tension. I did check and tweak my collimation after quite a long time of not doing it, and was pleased to see that only a little adjustment was needed. I could have made the nebula a lot brighter, but chose to keep it more true to the dynamic range and realistically subtle. Finally, I had a lot of nasty glare and reflection from γ Cas (which figured into my decision to hold off on pulling the nebula way up); it’s hard to handle such a bright star in the field of view when taking 600 s subframes! (Thank goodness for layer-masked Levels.) Nevertheless, this is a much better result than I’ve gotten previously for this target.

Date: 1, 14 Nov 2017

Subject: IC 63, γ Cassiopeiae Nebula, the “Ghost of Cassiopeia”

Scope: AT8IN + High Point Scientific coma corrector

Filters: ZWO 31 mm diameter unmounted Hα, OIII (7 nm bandpass)

Mount: EQ-6 (EQMOD 2.000j)+PEC

Guiding: Orion Thin Off-axis Guider + DSI +PHD 2.6.4.4 (Win 10 ASCOM) using predictive PEC algorithm

Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21

Acquisition: Sequence Generator Pro 3.0.0.3

Exposure: 41x600 Hα, 20x600 OIII

Stacking: Neb 4.1.6, flats & darks, trans+rot align, Nebulosity 1.5σ stack and align.

Processing: StarTools 1.4.328: Aggressively stretched and deconvoluted Hα channel in StarTools; was less aggressive about OIII because I didn’t see much detail in it. Aligned the processed layers in Nebulosity then combined in Photoshop using Annie’s Astro Actions’ Hubble Palette module. Several rounds of layer-masked levels to get rid of nasty reflections around γ Cas. A bit more curves. Deep Space and Space Noise Reduction. AstroFrame.