The Crescent Nebula in Cygnus



Optics/Mount: CPC1100 with f6.3 Celestron reducer on a Milburn Wedge. Dec antibacklash set to 27/27. PEC on.
Camera: SXVR-H694
Exposure: Total exposure time 17 hours; Ha:OIII 26:25 x 20 minutes. All bin 1x1.
Filters: Astrodon 5nm SII and Ha, 3nm OIII
Date: Data was collected over 17 nights from July 30 to September 13, 2015.

Imaging automation and capture: Sequence Generator Pro

Guiding Hardware: ASI120MM, Celestron off axis guider. Guiding scale 0.92 arcsec/pixel. 1 second guide exposures.
Focusing: Rigel Systems GCUSB/nStep on stock C11 focuser
Guiding Software: PHD2. Aggressiveness 80, Hysteresis 0, Minimum Move 0.7, Max RA 1000, Max Dec 600. Guiding binned with WDM connection. Dec set to hysteresis. Dithering set to Extreme with Settle < 1.2.
Guiding performance: FWHM of subs about 1.2 arc seconds, RMS in PHD about 0.7 arcsecs.
Light pollution: Bortle 8 (white zone, NELM about mag 4.5)
Image scale at capture: 0.6 arcsecs/pixel = f/5.7
Scale of presentation: 1.2 arcsecs/pixel (50% resample)
Processing: Bias, darks, and flats. Stacked and processed with PixInsight, with a few minor modifications in Photoshop.