Astronomy Picture Of the Day (APOD)Sunset at the Portara
Today, the Sun crosses the celestial equator heading north at 11:44 UT. Known as an equinox, this astronomical event marks the first day of spring in the northern hemisphere and autumn in the south. It also marks the beginning of Norouz, the Persian (Iranian) new year. Equinox means equal night.
Saturn: Moons in Transit
Every 14 to 15 years, Saturn's rings are tilted edge-on to our line of sight. As the bright, beautiful rings seem to grow narrower it becomes increasingly difficult to see them, even with large telescopes. But it does provide the opportunity to watch multiple transits of Saturn's moons.
GLOBE at Night: Help Track Light Pollution
How many stars can you see? Through next week, the GLOBE at Night project invites people from all over the world to go outside at night, look up, and see! Specifically, people are invited to go out an hour after sunset and look for the constellation Orion toward the west.
Tychos Supernova Remnant
What star created this huge puffball? Pictured above is the best multi-wavelength image yet of Tycho's supernova remnant, the result of a stellar explosion first recorded over 400 years ago by the famous astronomer Tycho Brahe.
Martian Moon Deimos from MRO
Mars has two tiny moons, Phobos and Deimos. Pictured above, in a recently release image by HiRISE camera onboard the Mars-orbiting Mars Reconnaissance Orbiter (MRO), is Deimos, the smaller moon of Mars. Deimos is one of the smallest known moons in the Solar System measuring only about 15 kilometers across.
A Prominent Solar Prominence from SOHO
What's happened to our Sun? It was sporting a spectacular -- but not very unusual -- solar prominence. A solar prominence is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field.
Haute Provence Star Trails
Fix your camera to a tripod and you can record the graceful trails traced by the stars as planet Earth rotates on its axis. For example, this dramatic 5 hour long exposure was made on February 24 from Haute-Provence Observatory (OHP) in southeastern France.
Hickson Compact Group 90
Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups (HCGs). This sharp Hubble image shows one such galaxy group, HCG 90, in startling detail.
Thor s Helmet (NGC 2359) and Planetary Nebula
At the right, Thor's Helmet (NGC 2359) seems to gaze across a lovely star field. The broad skyscape itself covers about 1.5 degrees or 3 full moons toward the constellation Canis Major.
The striking X near the center of this lunarscape is easily visible in binoculars or a small telescope. Yet, not too many have seen it. The catch is, this lunar X is only apparent during a four hour period just before the Moon's first quarter phase.