Hickson 61 Galaxy Group

This galaxy group comprises (clockwise from the elongated blue galaxy) NGC4173, NGC4169, NGC4174 and NGC4175. Their magnitudes are 13.6, 13.2, 14.4 and 14.2 respectively. NGC4173 is a foreground object at an estimated distance of 43 million light years (mly) while the other three are around 170 mly distant.

The galaxies were discovered by Sir William Herschel in 1785. In 1982 the group was included in a collection of compact galaxy groupings published by Paul Hickson (Hickson, Paul (1982). “Systematic properties of compact groups of galaxies”. Astrophysical Journal. 255: 382–391).

This group also goes by the nickname ‘The Box’ because its members lie at the corners of a rectangle.

Exposure times were 7 hours (Lum) and 7.5 hours each through red, green and blue filters.

Equipment: Planewave CDK14 corrected Dall-Kirkham telescope on a 10Micron GM2000 mount,  ZWO ASI6200 CMOS camera, Astrodon LRGB filters, Monster Moag off-axis guider with Starlight Xpress UltraStar guide camera.

Acquisition software: ACP Expert Scheduler, Maxim/DL. Image processing: PixInsight.