APOD: 2025 October 21 Б IC 1805: The Heart Nebula
21.10.2025

What electrifies the Heart Nebula? First, the large emission nebula on the left, catalogued as IC 1805, looks somewhat like a human heart. The nebula glows brightly in red light emitted by its most prominent element, hydrogen, but this long-exposure image was also blended with light emitted by sulfur (yellow) and oxygen (blue).

IC 1805: The Heart Nebula
11.09.2019

What energizes the Heart Nebula? First, the large emission nebula dubbed IC 1805 looks, in whole, like a human heart. The nebula glows brightly in red light emitted by its most prominent element: hydrogen. The red glow and the larger shape are all powered by a small group of stars near the nebula's center.

Stars and Dust of the Lagoon Nebula
8.09.2003

The large majestic Lagoon Nebula is home for many young stars and hot gas. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebulae is so big and bright that it can be seen without a telescope toward the constellation of Sagittarius.

APOD: 2026 May 13 Б NGC 188: Old Cluster in the New General Catalog
13.05.2026

The New General Catalog of star clusters and nebulae really isn't so new. In fact, it was published in 1888 - an effort by J. L. E. Dreyer to consolidate the work of astronomers William, Caroline, and John Herschel along with others into a useful single, complete catalog of astronomical discoveries and measurements.

Star Clusters Young and Old
10.09.2006

Many stars form in clusters. Galactic or open star clusters are relatively young swarms of bright stars born together near the plane of our Milky Way Galaxy. Separated by about a degree...

M46 Plus Two
17.04.2015

Galactic or open star clusters are young. These swarms of stars are born together near the plane of the Milky Way, but their numbers steadily dwindle as cluster members are ejected by galactic tides and gravitational interactions. In fact, this bright open cluster, known as M46, is around 300 million years young.

Collinder 399: The Coat Hanger
23.12.2008

Is this coat hanger a star cluster or an asterism? This cosmic hang-up has been debated over much of last century, as astronomers wondered whether this binocular-visible object is really a physically associated open cluster or a chance projection. Chance star projections are known as asterisms, an example of which is the popular Big Dipper.

The Lagoon Nebula in Stars Dust and Gas
24.09.2014

The large majestic Lagoon Nebula is home for many young stars and hot gas. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebula is so big and bright that it can be seen without a telescope toward the constellation of Sagittarius.

NGC 281: The Pacman Nebula
23.08.2005

NGC 281 is a busy workshop of star formation. Prominent features include a small open cluster of stars, a diffuse red-glowing emission nebula, large lanes of obscuring gas and dust, and dense knots of dust and gas in which stars may still be forming.

NGC 281: Cluster, Clouds, and Globules
21.09.1998

NGC 281 is a busy workshop of star formation. Prominent features include a small open cluster of stars, a diffuse red-glowing emission nebula, large lanes of obscuring gas and dust, and dense knots of dust and gas in which stars may still be forming.