APOD: 2024 September 17 – Melotte 15 in the Heart Nebula

Good Constitution Day morning, Rallypoint, and welcome to the September 17th edition of Astronomy Picture of the Day (APOD). The Heart Nebula (IC 1805) is located 7,500 light years from Earth in the constellation Cassiopeia. It was first discovered by German astronomer and composer William Herschel in November 1787. Inside the Heart Nebula we find the star cluster Melotte 15, rendered in a traditional Hubble palette of reds, greens, and blues indicating the presence of ionized hydrogen, sulfur, and oxygen. British astronomer Philibert Melotte published his catalog of 245 star clusters in 1915. Based on what we understand of astrophysics, scientists estimate that Melotte 15 is only 1.5 million years old. Cheers.