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The Hole in the Trees Skybox | all galleries >> Deep Sky >> Planetary Nebulae > Abell 39
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Abell 39

PK 047+42.1 in Hercules

This is an OIII/RGB image. The stars are from RGB data, and the nebula is OIII. The nebula is very blue, even showing up faintly in the 60-second blue images, so I mapped the OIII data to a deep teal blue (hue 195).

Optics/Mount: CPC1100 with f6.3 Celestron reducer on a Milburn Wedge. Dec antibacklash set to 27/27. PEC on.
Camera: SXVR-H694
Exposure: 8 hours total. 17x20 min OIII, 40:42:50 x 60 seconds RGB, all bin 1x1.
Filters: Astrodon Type IIc RGB and 3nm OIII
Date: 6 nights from June 8 to July 2, 2014

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: PHD. Aggressiveness 80, Hysteresis 0, Minimum Move 0.9, Max RA 1000, Max Dec 600. Dec set to auto/resist switching. Dithering set to Extreme with Settle < 1.2.
Guiding performance: HFR of subs about 1.2 arc seconds, RMS in PHD about 0.5 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: 0.9 arcsecs/pixel
Processing: Darks, bias, and flats. Stacked with Deep Sky Stacker, post-processed with Photoshop CS2 and Fitswork (for gradient removal).

other sizes: small medium large original auto
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