Discovered by Giovanni Batista Hodierna before 1654.
M34 is a bright open cluster of stars in the constellation of Perseus. The estimated distance to the cluster is approximately 1,500 light years. The cluster is visible with the aid of binoculars and is readily resolved even in small amateur telescopes. The visual diameter of the cluster is a little larger than that of the full Moon. This equates to a diameter of about 15 light years. The age of the cluster is estimated to be between 200 and 250 million years.
1https://en.wikipedia.org/wiki/Messier_34