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NGC 6871 – A Hydrogen Region in Cygnus


NGC 6871 annotated

July 23rd, 2018

This is a rather obscure target, and that is part of why I imaged it. I doubt many people have paid attention to this region so I thought I would. In order to show where exactly this is on the sky (because the catalog number does not exactly help) I decided to create an annotated view (above). NGC 6871 is actually the designation for the small open cluster on the very right hand edge of the image. The rest of the image is filled with hydrogen gas and dotted with a few interesting dark nebulae. The catalog numbers for this area are shown in the annotated view. I think this image turned out well, the only thing that caused me problems was that there was too much ionized hydrogen in this frame! Because of this a lot of the objects in the frame appeared very low in contrast, lost in a sea of hydrogen. I did some work on this, but you can still look at the image and see that it is predominantly red, as it is mostly hydrogen. The only neutral areas are a small hole in the upper right and side (I believe caused by stellar wind) and the dark nebulae in the image.

Captured on: June 12th, 15th, and 21st, 2018

AT6RC, 896mm @ F/5.9

ZWO ASI 1600mm-C
ZWO filters
Skywatcher NEQ6 Pro
Orion SSAG


Hydrogen alpha: ZWO 7nm Ha filter(1.25″), 70x180s, -10C, 1×1 bin, Gain 200, Offset 50

Luminance: Astronomik CLS filter(1.25″), 30x120s, -10C, 1×1 bin, Unity Gain
Red: ZWO Red filter(1.25″), 60x60s, -10C, 1×1 bin, Unity Gain
Green: ZWO Green filter(1.25″), 60x60s, -10C, 1×1 bin, Unity Gain
Blue: ZWO Blue filter(1.25″), 60x60s, -10C, 1×1 bin, Unity Gain

Total Acquisition of 7hrs, 30 minutes


Thanks for looking!