NGC772 Unbarred Spiral Galaxy

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2015/11/15 - NGC 772 (also known as Arp 78) is an unbarred spiral galaxy approximately 130 million light-years away in the constellation Aries. Around 200,000 light years in diameter, NGC 772 is twice the size of the Milky Way Galaxy, and is surrounded by several satellite galaxies – including the dwarf elliptical, NGC 770 – whose tidal forces on the larger galaxy have likely caused the emergence of a single elongated outer spiral arm that is much more developed than the others arms. Halton Arp includes NGC 772 in his Atlas of Peculiar Galaxies as Arp 78, where it is described as a 'Spiral galaxy with a small high-surface brightness companion'. Two supernovae (SN 2003 hl & SN 2003 iq) have been observed in NGC 772. NGC 772 probably has a H II nucleus, but it may be a transitional object.


Object information
Name : NGC772 Unbarred Spiral Galaxy
Type : Galaxy
Constellation : Aries
Distance : 130M light-year
Apparent dimensions : 7'.2 × 4'.3
Apparent magnitude : 11.10

Image information
Image date : 2015/11/15, 2015/11/16
Right ascension : 1:59:20.608
Declination : 19°0' 0.53"
Focal length : 1685.56 mm
Focal ratio : f/6.64
Image resolution : 0.661 arcsec/pixel
Field of view : 34' 56.1" x 27' 17.5"
Sky quality : 21.5 mag/arcsecond2
Sensor temperature : -20°C
Light frames : 6 hours total exposure time
24x 900 sec. luminance unbinned
Image acquisition with ACP Observatory Control Software, ACP Scheduler and Maxim DL
Auto-guiding with Maxim DL
Auto-focusing with FocusMax
Bias frames : None
Dark frames : None
Flat frames : None
Processing : PixInsight for calibration, alignment and integration.
Adobe Photoshop CS6 for final touch.

Equipment information
Telescope : Orion Optics 10" ODK
Corrector : None
Focuser : Baader SteelTrack with SteelDrive
Mount : Mesu Mount 200 with Sidereal Technology SiTech Controller
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 : www.sunstarfrance.com, Hautes-Alpes, France