NGC 281: the Pacman Nebula in Cassiopeia

c3580bfedd5e49c846cb830203961cf4.1824x0_q100_watermark_watermark_opacity-10_watermark_position-4_watermark_text-Copyright Pekka Simell

NGC 281 is an H II region in the constellation of Cassiopeia and part of the Perseus Spiral Arm. It includes the open cluster IC 1590, the multiple star HD 5005, and several Bok globules. Colloquially, NGC 281 is also known as the Pacman Nebula for its resemblance to thevideo game character.

The nebula was discovered in August 1883 by E. E. Barnard, who described it as “a large faint nebula, very diffuse.” The multiple star HD 5005, also called \beta1, was discovered by S. W. Burnham. It consists of an 8th-magnitude primary with four companions at distances between 1.4 and 15.7 seconds of arc. There has been no appreciable change in this quintuple system since the first measurements were made in 1875.

The nebula is visible in amateur telescopes from dark sky locations.

Imaging cameras: Atik 383L+
Mounts: Astro-Physics Mach 1 GTO
Guiding telescopes or lenses: Teleskop Service 10″ Newton F4.8
Guiding cameras: Orion StarShoot Autoguider
Focal reducers: ASA 2″ x 0,73 Corrector/Reducer 2KORRR
Software: PixInsight PixInsinght 1.8 RC7
Filters: Baader Planetarium Baader 2″ Narrowband Set
Dates: Sept. 5, 2013, Sept. 6, 2013, Nov. 6, 2013
Frames:
Baader Planetarium Ha 7nm: 22×400″ -20C bin 1×1
Baader Planetarium OIII 8.5nm: 20×400″ -20C bin 2×2
Baader Planetarium SII 8nm: 20×400″ -20C bin 2×2
Integration: 6.9 hours
Darks: ~11
Flats: ~20
Flat darks: ~20
Bias: ~20

Autor: Pekka Simell

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15 January 2014

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