NGC4631 and 4656 in LHaRGB (CCanes Venatici) , April 2023
Planewave CDK12.5" telecope and A-P 1100GTO AE mount
ASI6200MM Camera, Antlia Pro BB & 3nm Ha Filters
Lum (28 x 200s exposures, Bin 2x2, Gain 100)
RGB (3 x 20 x 240s exposures, Bin 2x2 Gain 100)
Ha (13 x 600s exposures, Bin 2x2, Gain200)
Total Integration Time = 7.7 hours
The two large galaxies, The Whale, NGC4631 and The Hockey stick, NGC4656 are popular image targets as both are peculiarly shaped. For some reason, only NC4631 is listed in the Arp catalogue of peculiar galaxies as Arp281. Much of their strangeness results in the tidal forces both are exerting on each other, together with even closer dwarf galaxies.
The Whale Galaxy is home to a central starburst region, as well as giving off a very strong hydrogen (red) signal, indicating a lot of intense stars formation here. These large and bright, but shortlived stars also make NGC4631 a home to very many supernovae. These supernovae are blowing gas out of the galactic plane, adding to the odd shape of this otherwise edge on barred spiral galaxy.
The Hockey Stick is considered a highly warped barred spiral, but the main culprit here is thought to be galactic gravitational interactions. Far less star forming activity is noted in NGC4656. At 7000 light years in diameter (apparent lenght), this hockey stick eclipses the earth's largest hockey stick which is located outside the Duncan recreational centre in B.C., Canada.