This image of entry 271 in Halton Arp's Atlas of Peculiar Galaxies, which is comprised of NGC 5426, here on the left, and 5427 on the right, is my attempt at the 2nd of two standout pairs of interacting spiral galaxies in Virgo, and follows my post on the other pair, NGC 4567/4568, which is often referred to as the "Butterfly". 

To recap from my earlier post, the Butterfly and Arp 271 have striking and starkly different morphologies, but they are challenging targets, given the smaller angular scales on which the "action" is taking place in both, and there are relatively few images of either object on Astrobin, especially Arp 271, of which there is only a relative handful. An added challenge with Arp 271 for many observers is its low altitude, even at culmination: from the Sierra Remote Observatories, where my telescope is stationed, it reaches a maximum of just under 47 degrees. 

I've had these targets on my bucket list for a long time, finally taking my turn at imaging both this spring as a small project, and I've posted the resulting images one right after the other, and at the same plate scale (about 0.62"/pixel), to hopefully create an interesting juxtaposition. Part of what makes the two pairs so eye-catching is that their spirals have such different relative orientations. 

Arp 271 is at a distance of about 130 million lights years, about twice as far away as the Butterfly, and at that distance, the galaxy cores are separated by about 90,000 light-years, somewhat less than the diameter of the spirals. Unlike the galaxies in the Butterfly, which are about four times closer to one another, and are in the early stages of a collision, it is not certain if those in Arp 271 will also collide. On the other hand, the morphology of the pair shows clear signs that the galaxies have been shaped by tidal interactions, the most notable feature being an elegant bridge-like connection running between them. The spiral arms in NGC 5426 also seem stretched out on the left, compared with the side that is closer to its neighbour, while an outer arm of NGC 5427 that arcs over the top seems to be drawn out to and down towards NGC 5426. More "direct" evidence of the interaction comes from a recent study that used spectroscopic measurements to produce maps of the the motion of hydrogen gas in and around NGC 5427, which suggest that material that is falling into that galaxy from outside its disc has been transferred from NGC 5426. 

This image is the result of about 9 hours of integration in luminance, and 7 hours in RGB colour, and was taken over the course of ten nights in April and May. The field-of-view of this crop is about 26'x22'.