The Ring Nebula in Lyra
This is a blend of Ha and OIII data. The core of the nebula uses Ha:OIII:OIII for Red:Green:Blue. The halo uses Ha for luminance, and Ha:OIII:OIII for color.
Optics/Mount: CPC1100 with f6.3 Celestron reducer on a Milburn wedge. Dec antibacklash set to 27/27. PEC on.
Exposure: Total exposure time about 16.7 hours; 32 x 20 mins Ha, 18 x 20 mins OIII. All bin 1x1.
Filters: Astrodon 5nm Ha and 3nm OIII
Date: Data was collected over 6 nights from May to July 2015.
Imaging automation and capture: Sequence Generator Pro
Guiding Hardware: ASI120MM, Celestron off axis guider. Guiding scale 0.46 arcsec/pixel. 1 second guide exposures.
Focusing: Rigel Systems GCUSB/nStep on stock C11 focuser
Guiding Software: PHD2. RA aggressiveness 55, hysteresis 0, Minimum Move 1.4 arcsecs, Max RA 200, Max Dec 600. Guiding unbinned with ZWO connection. Dec set to hysteresis. Dithering set to Extreme with Settle < 1.2.
Guiding performance: FWHM around 2.3 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: 100%
Processing: Bias, darks, and flats. Stacked and processed with PixInsight, with a few minor modifications in Photoshop.