M81 and M82

The galaxies M81 and M82 are one of the best-known pairs of galaxies and an ideal target due to their good visibility. They are located in the constellation Ursa Major and are visible for a good part of the year from January to summer depending on the observation location in the northern hemisphere.

Located about 12 million light-years from us, which implies that they belong to our closest neighbors on a cosmic scale, they present a surprising particularity. Indeed, one is getting closer to us while the other is moving away. Thus, M82, called the cigar galaxy because of its oblong shape (on the left of the image), is moving away from us. M81, on the right, seems to be getting closer. However, it would seem that M82 is actually in orbit around M81 since their distance is only 120,000 light-years.

The effects of gravitational tides are therefore very strong and have a marked impact on M82, the center of which is seen to have a high intensity, probably also due to the presence of a supermassive black hole. Its distance would thus be only an illusion due to its orbit.

The image presented is the result of a color layer captured with the ZWO 533mc pro camera as well as a Hydrogen alpha layer photographed using an Optolong L-Ultimate filter. The exposure time being relatively modest, 7h30 for the color and about 3h for the Ha, the processing is rather complicated and requires a good knowledge of PixInsight.

Equipment:
80ed Skywatcher
Am5
Asiair plus
ZWO 533mc pro
EAF
Optolong L-Ultimate filter
Optical splitter
Stacked in Siril
Processed in PixInsight