ARP 171 is situated in Virgo and consists of NGC 5718 and other related galaxies in the cluster interacting with neighboring IC 1042 (PGC52433). The galaxies are classified within the diffuse counter tail category. There is a halo/ multiple shell structure that surrounds NGC 5718 and IC 1042 and extends visually out to PGC 1253615 (distance 360 million light years) in the upper right and PGC 52452 (distance 407 million light years) on the lower left.
NGC 5718 is 417 million light years away from here. The Small blue galaxy to the upper left of NGC 5718 is PGC52451 which is 505 million light years away, and the spiral galaxy below NGC 5718 is PGC52434 at a distance of 391 million light years.
To give a bit of perspective PGC 1251904 which is the smaller galaxy diagonally to the lower right of NGC 5718 is at a distance of 1.2 billion light years. The light from NGC 5718 left the galaxy during the Devonian period on Earth. This period ushered in the first life on dry land with the formation of forests and plants. Within the ocean’s fish (placoderms became dominant).
When the light we see from PGC 1251904 began its journey here 1.2 billion years ago Earth was in the Mesoproterozoic Era. This marked the beginning of the appearance of multi cellular life in the form of jellyfish, worms and sponges.
Things have changed quite a bit since then.
Imaged in LRGB on our PlaneWave CDK 1000 at Observatorio El Sauce, Chile.
Image Processing: Mike Selby
www.throughlightandtime.com