NGC281 Pacman Nebula

mouseover for annotation

view full size

2012/08/03 - A short first night, clouds came in and I had to stop, but still managed to get some data. Still struggling with my coma corrector. Hopefully the weather will be better soon, so I can add some data to this object. Added some extra data and used Maxim DL for capturing and guiding.

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 the video 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 , 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.


Object information
Name : NGC281 Pacman Nebula
Type : Nebula
Constellation : Cassiopeia
Distance : 9.500 light-year
Apparent dimensions : 35'
Apparent magnitude : 7.40

Image information
Image date : 2012/08/03
Right ascension : 0:52:59.300
Declination : 56°37' 19.00"
Focal length : 0.00 mm
Focal ratio : 
Image resolution : 0.000 arcsec/pixel
Field of view : 
Sky quality : 19.70 magnitude/square arcsecond
Guiding rms : 0.35 x 2 = 0.70 x guiding imagescale 1.3 arcsec/pixel = 0.91 arcsec
Sensor temperature : 0°C
Light frames : 8 hours, 38 minutes total exposure time
3x 120 sec. RGB unbinned (starcolor)
9x 1200 sec. hydrogen-alpha unbinned
9x 1200 sec. oxygen-III unbinned
7x 1200 sec. sulfur-II unbinned
Image acquisition scripted with Nebulosity v3 & Maxim DL
Auto-guiding with PHD (medium dither, settle < 0.3) & Maxim DL
Bias frames : 100x unbinned
Dark frames : Bap pixel map
Flat frames : 5x hydrogen-alpha unbinned
5x oxygen-III unbinned
5x sulfur-II unbinned
Created with Gerd Neumann Aurora flatfield panel
Processing : PixInsight for calibration (bias frames, bad pixel map and flat frames), alignment and integration.
Adobe Photoshop CS6 for final touch.

Equipment information
Telescope : Sky-Watcher BKP250 10" 1200mm f/4.8 Newtonian
Corrector : Guan Sheng Optical 2" coma corrector and field flattener
Focuser : Moonlite CR newtonian focuser with DC motor and USBnFocus adapter
Mount : Sky-Watcher NEQ6-Pro german equatorial mount controlled with EQMOD via HiTec Astro EQDir
Camera : QSI 683wsg-8 cooled CCD camera with Kodak KAF-8300 sensor and Off Axis Guide (OAG) port
Guidecamera : Starlight Xpress Lodestar autoguider
Filters : Astrodon Tru-Balance E-Series LRGB & Astrodon 3nm H-α, 3nm O-III, 3nm S-II and 3nm N-II
Observatory site : Etten-Leur, The Netherlands