Melotte 15 RedCat 51, QHY minicam8 mono, on Hem27ec. 22 x 600s Ha, 32 x 600s OIII and SII, 20 x 60s RGB. Unguided

Melotte 15

Melotte 15 is a striking open star cluster located at the center of the Heart Nebula (IC 1805 or Sh2-190) in the constellation Cassiopeia, roughly 7,100–7,500 light years from Earth.​
It is part of the Perseus Arm of the Milky Way and is often called the “Heart of the Heart”because it illuminates the surrounding emission and reflection nebula.​

The cluster includes several massive, young stars—some up to 50 times the mass of the Sun—that formed only about 1.5 million years ago. Their intense radiation sculpts the surrounding gases into intricate shapes of hydrogen, sulfur, and oxygen, giving the nebula its iconic red, green, and blue hues. Over time, these stellar winds and radiation will erode the nebula, leaving behind a clean cluster of young stars.​​

Historically, Melotte 15 was catalogued by Philibert Jacques Melotte in 1915 and later identified with other designations like Collinder 26.​