The Spider & Fly Nebula - IC417 & NGC1931 - Ha(HaR)GB

This colorful area of space rich in hydrogen and oxygen gas is located constellation Auriga.  Along with other nearby space oddities such as the open star cluster M38, emission nebula IC410 with Tadpoles and the Flaming Star Nebula, the Spider Nebula - IC417 and the Fly Nebula - NGC1931 make for a wonderful place to image.  I am not quit sure I see a spider or a fly but nevertheless, it is gorgeous.  The emission nebula (Spider) contains an open cluster consisting of hot young stars and is about 100 ly across and 10,000 ly away.  The Fly is both an emission and reflection nebula but only about 10 ly across.

Processing had its usual weirdness.  This is the third time I had trouble stacking narrowband data in PI.  This time it was the Hydrogen alpha subframes.  It stacked everything but the Ha stacked image looked like a negative or something - it has happened on the last two sulfur images I did and though it was limited to just that.  The RGB stacked nicely.  Oh well, fortunately DSS worked like a charm.

I made a combined layer for the red channel (50% Ha - 50% red) rather than straight Ha as it just looked better and then added Ha as a luminosity layer (70%) to make the final image.  I really wanted to keep the Ha nebulosity but also wanted to keep it somewhat natural so I had to do a lot of balancing.  Göran Nilsson posted a really good version of the Spider and Fly on Astrobin (https://www.astrobin.com/ezdye1/E/?page=3&nc=all) recently which convinced me to image this.  I also did not crop it much at all (what a surprise) as I like faint Ha regions that are visible on the outer edges.

 

IC417 - Spider Nebula & NGC1931 - Fly Nebula
Home Monroe, CT
Date: 1-21-20, 1-22-20, 1-24-20
Camera: ZWO ASI1600MM-Pro
Telescope: Astro-Tech AT115EDT 115mm Refractor Telescope
Barlow: None
Focal Length: 805mm
f/7
Focal Reducer: Astro-Tech 0.8x Focal Reducer/Field Flattener for Refractor Telescopes
Mount: Orion Sirius
Filter Wheel: ZWO EFW 8 x 1.25"
Filter: ZWO Ha, R, G, B
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Agena 50mm Guide Scope with Helical Focuser
Exposure: Ha 92 x 180s, R 41 x 90s, G 37 x 90s, R 34 x 90s
Gain: 139
Offset 21
Temp: -4 C
Processing: APT, DSS, PixInsight, Photoshop
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