M46 Open Cluster in Puppis

Classified as a medium size open cluster M46 contains approximately 500 stars and lies at a distance of 5,500 light years. (ly) This is an LRGB image with 21 minutes of integration time per filter. Within can be seen a small ring-shaped planetary nebula designated NGC 2438, which at 1,370 ly is much closer to us. It has a diameter of 1 arc minute but there is a larger outer shell about twice that size , however, longer exposure times are needed to pull it out from the background.