Object: Constellation: Coordinates: Size: Brightness:
NGC 3718 UMa 11h33m / +5304' 8.1' x 4' 10.6mag
NGC 3729 UMa 11h34m / +5308' 2.8' x 1.9' 11.0mag

The warped spiral galaxy NGC 3718 (top) and the spiral galaxy NGC 3729 (bottom) in the constellation of Ursa Major on March 8 / 9, 2014. The two are likely interacting gravitationally, accounting for the peculiar appearance of NGC 3718. The pair is about 52 million light-years away from earth. To the upper right of NGC 3718, the Hickson 56 group of galaxies can be seen. It lies over 400 million light years away. NGC 3718 and NGC 3729 were discovered by William Herschel in 1789 (source: http://apod.nasa.gov/apod/ap130803.html, Wikipedia).

On March 8 / 9, 2014, 63 3-minute exposures at ISO 800 were taken. Out of these, 21 3-minute exposures were added with the DeepSkyStacker software (resulting in a 1 hour 8 minutes exposure) and used for the dark background of the image. For the galaxies, all 63 3-minute exposures were used (stacked with DeepSkyStacker, Processed in Photoshop, added to the background image with a mask, resulting in a 3 hours 27 minutes exposure).
Equipment: Canon EOS 450D Baader modified camera, TeleVue Paracorr Type II coma corrector, 16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Lacerta off axis system (field of view comparison: image of the moon with the same equipment).


Search chart for NGC 3718 and NGC 3729. Map © 2014 "The Mag-7 Star Atlas Project", www.siaris.net. Map is slightly modified.