Movie: A Green Flash Over Italy
29.01.2007

How could the Sun turn green? Difficult to observe, the momentary green flash above the rising or setting sun has been documented as a phenomenon caused by the atmospheric bending or refraction of sunlight.

Antares and Rho Ophiuchi
22.09.1997

Why is the sky near Antares and Rho Ophiuchi so colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark.

IC 1795: The Fishhead Nebula
31.07.2019

To some, this nebula looks like the head of a fish. However, this colorful cosmic portrait really features glowing gas and obscuring dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia.

Perihelion Sun
11.01.1999

The Earth's orbit is not a perfect, sun-centered circle. At aphelion, the most distant point in Earth's orbit, the Sun is 150 million kilometers away and at perihelion, the closest point, Earth approaches the Sun to within about 147 million kilometers. While aphelion occurs in July, perihelion for planet Earth comes in January.

Three Nebulae in Narrow Band
2.11.2007

Narrow band filters and a false-color palette give these three nebulae a stunning appearance against the cosmic canvas of the central Milky Way. All three are stellar nurseries about 5,000 light-years or so distant, toward the nebula rich constellation Sagittarius.

Stars, Dust, and Gas Near Antares
26.01.2022

Why is the sky near Antares and Rho Ophiuchi so dusty yet colorful? The colors result from a mixture of objects and processes. Fine dust -- illuminated from the front by starlight -- produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae.

Dark Ball in Inverted Starfield
6.11.2022

Does this strange dark ball look somehow familiar? If so, that might be because it is our Sun. In the featured image from 2012, a detailed solar view was captured originally in a very specific color of red light, then rendered in black and white, and then color inverted.

APOD: 2024 May 1 Б IC 1795: The Fishhead Nebula
1.05.2024

To some, this nebula looks like the head of a fish. However, this colorful cosmic portrait really features glowing gas and obscuring dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia.

The Galactic Ring of NGC 6782
21.11.2001

Do spiral galaxies look the same in every color? NGC 6782 demonstrates colorfully that they do not. In visible light, NGC 6782 appears to be a normal spiral galaxy with a bright bar across its center.

Black Sun and Inverted Starfield
15.10.2012

Does this strange dark ball look somehow familiar? If so, that might be because it is our Sun. In the above image, a detailed solar view was captured originally in a very specific color of red light, then rendered in black and white, and then color inverted.