The Cat's Eye Nebula (Revisited)
4.07.1996

Three thousand light years away, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals "The Cat's Eye Nebula" to be one of the most complex planetary nebulae known.

MyCn18: An Hourglass Nebula
15.06.2002

The sands of time are running out for the central star of this hourglass-shaped planetary nebula. With its nuclear fuel exhausted, this brief, spectacular, closing phase of a Sun-like star's life occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf.

Shell Game in NGC 300
22.08.2002

Featured in color in yesterday's episode, big, beautiful, face-on spiral galaxy NGC 300 is seen here through a narrow filter that transmits only the red light of hydrogen atoms. Ionized by energetic starlight, a hydrogen atom emits the characteristic red H-alpha light as its single electron is recaptured and transitions to lower energy states.

MyCn18: An Hourglass Nebula
4.06.2000

The sands of time are running out for the central star of this hourglass-shaped planetary nebula. With its nuclear fuel exhausted, this brief, spectacular, closing phase of a Sun-like star's life occurs as its outer layers are ejected - its core becoming a cooling, fading White Dwarf.

APOD: 2025 February 23 Б Saturn in Infrared from Cassini
22.02.2025

Saturn looks slightly different in infrared light. Bands of clouds show great structure, including long stretching storms. Also quite striking in infrared is the unusual hexagonal cloud pattern surrounding Saturn's North Pole. Each side of the dark hexagon spans roughly the width of our Earth.

Symbiotic R Aquarii
10.07.2018

You can see it change in brightness with just binoculars over the course of a year. Variable star R Aquarii is actually an interacting binary star system, two stars that seem to have a close, symbiotic relationship.

MyCn18: An Hourglass Nebula
14.09.1997

The sands of time are running out for the central star of this hourglass-shaped planetary nebula. With its nuclear fuel exhausted, this brief, spectacular, closing phase of a Sun-like star's life occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf.

One Armed Spiral Galaxy NGC 4725
15.04.2015

While most spiral galaxies, including our own Milky Way, have two or more spiral arms, NGC 4725 has only one. In this sharp color composite image, the solo spira mirabilis seems to wind from a prominent ring of bluish, newborn star clusters and red tinted star forming regions.

Small Star
19.11.1999

A dim double star system cataloged as Gliese 623 lies 25 light-years from Earth, in the constellation of Hercules. The individual stars of this binary system were distinguished for the first time when the Hubble Space Telescope's Faint Object Camera recorded this image in June 1994.

APOD: 2025 April 21 Б Galaxy Lenses Galaxy from Webb
20.04.2025

Is this one galaxy or two? Although it looks like one, the answer is two. One path to this happening is when a small galaxy collides with a larger galaxy and ends up in the center. But in the featured image, something more rare is going on.