Imaged the planetary nebula M27 (The Dumbbell Nebula( on the nights of September 1 and X, 2023.  M27 has an apparent magnitude (v) of 7.5 and an apparent size of ~8x6 arcmin. 

Per NASA (reference:  https://www.nasa.gov/feature/goddard/2017/messier-27-the-dumbbell-nebula):  "Spotted by Charles Messier in 1764, M27 was the first planetary nebula ever discovered. The term “planetary nebula” is a bit of a misnomer based on the nebula’s round, planet-like appearance when viewed through smaller telescopes. The nebula is the result of an old star that has shed its outer layers in a glowing display of color. Also known as the Dumbbell Nebula, M27 resides more than 1,200 light-years away in the constellation Vulpecula. With an apparent magnitude of 7.5, the nebula can be spotted with a small telescope most easily in September." 

Imaged with a William Optics GT81 at F4.7 (382 mm focal length) using Flat6A II field flattener/0.8x reducer, UVIRcut and Optolong LeNhance dual narrowband filters, and ZWO ASI 533MC Pro. 
Total integration time of ~6 hours:
UVIRC filter = 90 subs at Gain = 100 with an exposure time of 120 seconds
LENH NB filter = 40 subs at Gain = 100 with an exposure time of 300 seconds

All images pre-processed using Pixinsight's weighted batch pre-processing script (WBPP) to perform calibration, debayering, registration, local normalization, and integration.  Background removed using GradXpert. 

OSC RGB image processing:  Initial post-processing in Pixinsight:  spectrophotometric color calibration, blur x terminator, and noise x terminator.  Masked stretch, generalized hyperbolic stretch, curves adjustment, HDR transformation using EasyHDR script, local histogram transformation, and color saturation adjustment.  Same processing used for both OSC RGB and NB (Ha and OIII processed separately) images.  Generated stars only version using StarXTerminator.

Narrowband image processing:  Initial post-processing in Pixinsight: blur x terminator and noise x terminator.  Separated out Ha (red) and OIII (green and blue) images.  For each of these images performed:  Masked stretch, generalized hyperbolic stretch, curves adjustment, HDR transformation using EasyHDR script, and local histogram transformation.  Generated starless versions of NB images and combined using SHO-AIP script to generate HOO starless image.  Final image generated by combining OSC RGB stars only and HOO starless images using Pixelmath process.


Original version:  M27 image generated from narrowband nebula and OSC RGB stars images

Rev B:  M27 OSC RGB image

Rev C:  M27 narrowband HOO starless image

Rev D:  M27 narrowband Ha starless image

Rev E:  M27 narrowband OIII starless image