Arp 293: More interacting galaxies
Astrophotographer Maurycy captured interacting galaxies Arp 293 (NGC 6285 and NGC 6286) along with neighboring galaxy UGC 10641, all at similar redshift, indicating a gravitationally bound trio. A distant galaxy cluster (LEDA 2582489) at z≈0.11 also appeared in the field. The 2.8-hour exposure suffered from walking noise due to guiding issues after the meridian flip.
Background
Arp (Atlas of Peculiar Galaxies) is a catalog of 338 unusual-looking galaxies compiled by astronomer Halton Arp in the 1960s. Many of these "peculiar" shapes turned out to be galaxies in the process of merging or interacting gravitationally. NGC 6285 and NGC 6286 are a well-known interacting pair, sometimes called the "Merging Dragons." Redshift (z) is a measure of how much light from a distant object has been stretched by the expansion of the universe — higher z means farther away. z=0.018 corresponds to roughly 250 million light-years; z=0.11 corresponds to about 1.5 billion light-years. A comoving distance accounts for the expansion of the universe, giving the current distance to a faraway object.