Celestial hemisphere:  Northern  ·  Constellation: Cygnus (Cyg)  ·  Contains:  Crescent Nebula  ·  HD191703  ·  HD192003  ·  HD192020  ·  HD192041  ·  HD192078  ·  HD192079  ·  HD192102  ·  HD192123  ·  HD192163  ·  HD192182  ·  HD192303  ·  HD192361  ·  HD192422  ·  HD192443  ·  HD192444  ·  HD192536  ·  HD192744  ·  HD228101  ·  HD228114  ·  HD228413  ·  HD228543  ·  LBN 193  ·  LBN 203  ·  LBN 208  ·  NGC 6888  ·  Sh2-105
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Crescent Nebula - NGC6888, John Pancoast
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Crescent Nebula - NGC6888

Getting plate-solving status, please wait...
Crescent Nebula - NGC6888, John Pancoast
Powered byPixInsight

Crescent Nebula - NGC6888

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Acquisition details

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Description

The Crescent Nebula traverses close to the zenith this time of year and therefore poses a guiding challenge for me. It surrounds a star that occasionally puffs out elements of its atmosphere which are then excited by the radiation from the central star. This image is 5 2/3 hours from the best of three nights in early September 2021. Taken with a one-shot color camera through a dual narrowband filter to capture Ha and OIII. Surrounded by the starfield and Ha nebulosity of the Milky Way, the nebula's OIII signal is weak but can be seen particularly in the slight blue halo around the nebula.

Capture: First time using the ASIair pro system and electronic auto focuser with my old iPadMini2 to control the mount. 68x5-minute lights, 20 each of darks, flats and flat darks.
Processing: Siril for calibration. Then crop for stacking artifacts, background extraction, background neutralization, histogram transformation, green noise reduction increased blue/green saturation and median filtering. This image was cropped even more from the original; elongated stars are still seen at all four corners. I have a field flattener/ reducer for this scope and obviously need to make use of it!

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Crescent Nebula - NGC6888, John Pancoast

In these public groups

NOVAC