Mars in View
6.12.2007

Very good telescopic views of Mars can be expected in the coming weeks as the Red Planet nears opposition on December 24th. Of course, opposition means opposite the Sun in planet Earth's sky - an arrangement that occurs every 26 months for Mars.

SN 1006 Supernova Remnant
1.08.2009

A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum.

Pacman and Hartley
7.10.2010

Touring the solar system with a 6 year orbital period, small comet Hartley 2 (103/P Hartley) will make its closest approach to planet Earth on October 20 and its closest approach to the Sun on October 28. It may become a naked-eye comet, just visible in clear, dark skies.

The Iris Nebula in a Field of Dust
1.08.2018

What blue flower grows in this field of dark interstellar dust? The Iris Nebula. The striking blue color of the Iris Nebula is created by light from the bright star SAO 19158 reflecting off of a dense patch of normally dark dust.

Flemings Triangular Wisp
27.07.2021

Chaotic in appearance, these tangled filaments of shocked, glowing gas are spread across planet Earth's sky toward the constellation of Cygnus as part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star.

Reflected Aurora Over Alaska
12.02.2013

Some auroras can only be seen with a camera. They are called subvisual and are too faint to be seen with the unaided eye. In the above image, the green aurora were easily visible to the eye, but the red aurora only became apparent after a 20-second camera exposure.

Perihelion Approaches
15.08.2015

This dramatic outburst from the nucleus of Comet 67P/Churyumov-Gerasimenko occured on August 12, just hours before perihelion, its closest approach to the Sun. Completing an orbit of the Sun once every 6.45 years, perihelion distance for this periodic comet is about 1.3 astronomical units (AU), still outside the orbit of planet Earth (at 1 AU).

APOD: 2025 December 28 Б NGC 1898: Globular Cluster in the Large Magellanic Cloud
28.12.2025

Jewels don't shine this bright -- only stars do. And almost every spot in this jewel-box of an image from the Hubble Space Telescope is a star. Now, some stars are more red than our Sun, and some more blue -- but all of them are much farther away.

Equinox at Saturn
25.08.2009

What would Saturn's rings look like if the ring plane pointed directly at the Sun? That situation occurred earlier this month when equinox occurred on Saturn. Since the Earth is nearly in the same direction as the Sun from Saturn, the rings appeared to disappear from Earth.

APOD: 2023 October 8 Б Plane, Clouds, Moon, Spots, Sun
8.10.2023

What's that in front of the Sun? The closest object is an airplane, visible just below the Sun's center and caught purely by chance. Next out are numerous clouds in Earth's atmosphere, creating a series of darkened horizontal streaks.