APOD: 2006 September 28- RCW 86: Historical Supernova Remnant
28.09.2006

In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism - a part of the sky identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest recorded supernova.

Sungrazer
22.03.2009

The Sun destroyed this comet. Arcing toward a fiery fate, this Sungrazer comet was recorded by the SOHO spacecraft's Large Angle Spectrometric COronagraph(LASCO) on 1996 Dec. 23. LASCO uses an occulting disk...

Julius Caesar and Leap Days
29.02.2024

In 46 BC Julius Caesar reformed the calendar system. Based on advice by astronomer Sosigenes of Alexandria, the Julian calendar included one leap day every four years to account for the fact that an Earth year is slightly more than 365 days long.

Cassini Spacecraft Crosses Saturns Ring Plane
29.12.2019

If this is Saturn, where are the rings? When Saturn's "appendages" disappeared in 1612, Galileo did not understand why. Later that century, it became understood that Saturn's unusual protrusions were rings and that when the Earth crosses the ring plane, the edge-on rings will appear to disappear.

A Rare Hybrid Solar Eclipse
3.11.2013

A spectacular geocentric celestial event of 2005 was a rare hybrid eclipse of the Sun - a total or an annular eclipse could be seen depending on the observer's location. For Fred Espenak, aboard...

R Leporis: A Vampire's Star
31.10.2018

Better known as Hind's Crimson Star, R Leporis is a rare star in planet Earth's night sky. It's also a shocking shade of red. The star's discoverer, 19th century English...

M44: The Beehive Cluster
30.04.2022

A mere 600 light-years away, M44 is one of the closest star clusters to our solar system. Also known as the Praesepe or the Beehive cluster its stars are young though, about 600 million years old compared to our Sun's 4.5 billion years.

Rotating Asteroid Bennu from OSIRIS REx
13.11.2018

Could this close-by asteroid ever hit the Earth? Eventually yes -- but probably not for a very long time, even though the asteroid is expected to pass inside the orbit of the Moon next century.

The Mystery of the Fading Star
8.01.2010

Every 27 years Epsilon Aurigae fades, remaining dim for roughly two years before growing bright again. Since the 19th century, astronomers have studied the mystery star, eventually arguing that Epsilon Aur, centered in this telescopic skyview, was actually undergoing a long eclipse by a dark companion object.

APOD: 2008 January 2- A Galaxy is not a Comet
2.01.2008

This gorgeous galaxy and comet portrait was recorded on December 30th, in the skies over Hoogeveen, The Netherlands. The combined series of 60 x 60 second exposures finds the lovely green coma of Comet 8P/Tuttle near its predicted conjunction with the Triangulum Galaxy.