Comet NEAT (Q4) Over Indian Cove
18.05.2004

Comet NEAT (Q4) was quite photogenic earlier this month. Although the head and part of the tails of Comet C/2001 Q4 (NEAT) were visible to the unaided eye, the best views of the colorful tail were revealed only later by cameras able to expose for long periods.

A Lunar Rille
29.10.2002

What could cause a long indentation on the Moon? First discovered over 200 years ago with a small telescope, rilles (rhymes with pills) appear all over the Moon. Three types of rilles...

The Tails of Comet NEAT Q4
12.05.2004

Comet NEAT (Q4) is showing its tails. As the large snowball officially dubbed Comet C/2001 Q4 (NEAT) falls toward the inner Solar System, it has already passed the Earth and will reach its closest approach to the Sun this coming Saturday.

Comet Lovejoy through Morby Castle Ruins
4.12.2013

This new comet is quite photogenic. Comet Lovejoy, discovered only three months ago, was imaged through ruins of ancient MЖrby Castle in Sweden last week sporting a green-glowing coma and tails trailing several degrees.

Dry Ice Sled Streaks on Mars
17.06.2013

What creates these long and nearly straight grooves on Mars? Dubbed linear gullies, they appear on the sides of some sandy slopes during Martian spring, have nearly constant width, extend for as long as two kilometers, and have raised banks along their sides.

Comet and Orion
2.10.2009

These colorful panels both feature a familiar northern hemisphere astronomical sight: the stellar nursery known as the Great Orion Nebula. They also offer an intriguing and unfamiliar detail of the nebula rich skyscape -- a passing comet.

Comet Hale Bopp Over Indian Cove
20.04.2004

Comet Hale-Bopp, the Great Comet of 1997, was quite a sight. No comets of comparable brightness have graced the skies of Earth since then. During this next month, however, even besides the fleeting Comet Bradfield, two comets have a slight chance of rivaling Hale-Bopp and a good chance of putting on a memorable sky show.

P2010 A2: Unusual Asteroid Tail Implies Powerful Collision
3.02.2010

What is this strange object? First discovered on ground based LINEAR images on January 6, the object appeared unusual enough to investigate further with the Hubble Space Telescope last week. Pictured above, what Hubble saw indicates that P/2010 A2 is unlike any object ever seen before.

APOD: 2026 March 20 Б Spring Equinox at Teide Observatory
20.03.2026

The defining astronomical moment of the equinox today is at 14:46 UTC (March 20). That's when the Sun crosses the celestial equator moving north in its yearly journey through planet Earth's sky, marking the beginning of spring for our fair planet in the northern hemisphere and fall in the southern hemisphere.

Mysterious Features on Ganymede
9.12.1997

Where is the rest of the circle? Jupiter's largest moon Ganymede has some truly unusual terrain, including the pictured half circle above cut by nearly parallel curves. Full circles can be easily explained by impact craters, but partial circles imply that some resurfacing has occurred since the original impact.