M5 - RB & Fake G (2019)

This is only my second image of M5, a globular star cluster residing in the galactic halo (area above and below the main disk).  Globular clusters are very old and M5 is certainly that at 13 billion years old.  At 25,000 light-years away in the constellation Serpens and approximately 165 light-years in diameter it contains more than 100,000 stars.

What do I mean by Fake G?  When I combined the RGB in PI in noticed a magenta splotch in many of the stars.  Upon further analysis I discovered they were only in the green channel.  I tried doing things in PI and PS with no success so I made a synthetic (fake) green channel by combining the Red and Blue using the PixelMath function in PI.  It worked as the splotches are gone.  

I am guessing the image would be better with a real green channel but it is orders of magnitude better than my embarrassing image from three years ago (https://astroquest1.blogspot.com/search?q=M5).  I will try to adjust the real green channel to improve the overall image after getting some suggestions from AB user Michael Feigenbaum.  I cropped the image a bit but wanted to keep the large star 5-Serpentis in the image and I prefer wider field images anyway.

Wide Field

Crop

M5 - Rose Cluster

Location: Home Monroe, CT

Date: 5-31-19, 6-3-19
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 8x 1.25"
Filter: ZWO R, G, B
Autoguiding: QHY-5L-II-M attached to an Agena 50mm Guide Scope with Helical Focuser
Exposure: R 58 x 60, G 53 x 60, B 60 x 60
Gain: 139
Offset 21
Temp: 8 C
Post Processing: PixInsight, Photoshop, Lightroom
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http://astroquest1.blogspot.com/