NGC3718 Galaxy

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2014/02/26 - Conditions were not too good. I needed to delete some frames because of passing clouds at the beginning of the session. The rest of the night was pretty good; FWHM between 2.44" and 2.84". Because of the clouds I wasn't able to shoot new flats, so I used old flats which don't function optimal. I also needed to crop off a reasonable big area with reflections, don't know what caused it, but I think I'll will remove the CCDT67 reducer. And I surely need to collimate the OTA again.

NGC 3718's spiral arms look twisted and extended, mottled with young blue star clusters. Drawn out dust lanes obscure its yellowish central regions. A mere 150 thousand light-years to the left is another large spiral galaxy, NGC 3729. The two are likely interacting gravitationally, accounting for the peculiar appearance of NGC 3718. While this galaxy pair lies about 52 million light-years away, the remarkable Hickson Group 56 can also be seen clustered beneath NGC 3718. Hickson Group 56 consists of five interacting galaxies and lies over 400 million light-years away.

Object information
Name : NGC3718 Galaxy
Type : Galaxy
Constellation : Ursa Major
Distance : 52M light-year
Apparent dimensions : 9' x 9'
Apparent magnitude : 10.50

Image information
Image date : 2014/02/26
Right ascension : 11:33:11.110
Declination : 53°4' 2.66"
Focal length : 1381.34 mm
Focal ratio : f/5.44
Image resolution : 0.806 arcsec/pixel
Field of view : 33' 10.1" x 22' 7.2"
Sky quality : 19.50 mag/arcsecond2
Sensor temperature : -30°C
Light frames : 7 hours and 30 minutes total exposure time
11x 900 sec. luminance unbinned
6x 900 sec. red unbinned
7x 900 sec. green unbinned
6x 900 sec. blue unbinned
Image acquisition with CCDAutoPilot and Maxim DL
Auto-guiding with Maxim DL
Auto-focusing with FocusMax
Bias frames : 100x unbinned
Dark frames : None
Flat frames : 12x luminance unbinned
12x RGB unbinned
Automated sky twilight flats with CCDAutoPilot
Processing : PixInsight for calibration, alignment and integration.
Adobe Photoshop CS6 for final touch.

Equipment information
Telescope : Robtics 10" 2000mm f/8 Ritchey Chretien
Corrector : Astro-Physics CCDT67 Focal Reducer
Focuser : Moonlite CS Ritchey Chretien focuser with high resolution stepper motor
Mount : ASA DDM60 Pro direct drive german equatorial mount controlled with AutoSlew
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