NGC5985, NGC5982, NGC5981 Draco Triplet

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2014/06/20 - Third light of our remote setup. We still needed 1 hour of red data, but I lost all patience after a period of three weeks of no imaging.

This intriguing trio of galaxies is sometimes called the NGC 5985/Draco Group and so (quite reasonably) is located in the northern constellation Draco. From left to right are face-on spiral NGC 5985, elliptical galaxy NGC 5982, and edge-on spiral NGC 5981 -- all within this single telescopic field of view spanning a little more than half the width of the full moon. While this grouping is far too small to be a galaxy cluster and has not been cataloged as a compact group, these galaxies all do lie roughly 100 million light-years from planet Earth. On close examination with spectrographs, the bright core of the striking face-on spiral NGC 5985 shows prominent emission in specific wavelengths of light, prompting astronomers to classify it as a Seyfert, a type of active galaxy. Not as well known as other tight groupings of galaxies, the contrast in visual appearance makes this triplet an attractive subject for astrophotographers. This impressively deep exposure of region also reveals faint and even more distant background galaxies.

Object information
Name : NGC5985, NGC5982, NGC5981 Draco Triplet
Type : Galaxy
Constellation : Draco
Distance : 100M light-year
Apparent dimensions : 5' x 5'
Apparent magnitude : 11.00

Image information
Image date : 2014/06/20, 2014/06/01, 2014/05/31, 2014/05/29, 2014/05/28
Right ascension : 15:38:39.513
Declination : 59°21' 16.27"
Focal length : 1687.36 mm
Focal ratio : f/6.64
Image resolution : 0.660 arcsec/pixel
Field of view : 35' 43.4" x 26' 57.3"
Sky quality : 21.50 mag/arcsecond2
Sensor temperature : -20°C
Light frames : 23 hours total exposure time
48x 900 sec. luminance unbinned
6x 1800 sec. red unbinned
8x 1800 sec. green unbinned
8x 1800 sec. blue unbinned
Image acquisition with ACP Observatory Control Software, ACP Scheduler and Maxim DL
Auto-guiding with Maxim DL
Auto-focusing with FocusMax
Bias frames : 100x unbinned
Dark frames : None
Flat frames : 24x luminance unbinned
24x RGB unbinned
Automated sky twilight flats with ACP
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 :, Hautes-Alpes, France