Anemic Spiral NGC 4921 from Hubble
15.05.2019

How far away is spiral galaxy NGC 4921? It's surpringly important to know. Although presently estimated to be about 300 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe.

The X Ray Sky from eROSITA
23.06.2020

What if you could see X-rays? The night sky would seem a strange and unfamiliar place. X-rays are about 1,000 times more energetic than visible light photons and are produced by violent explosions and high temperature astronomical environments.

Rosetta s Target Comet
23.05.2014

The Rosetta spacecraft captured this remarkable series of 9 frames between March 27 and May 4, as it closed from 5 million to 2 million kilometers of its target comet. Cruising along...

Comet Garradd Passes Ten Thousand Stars
3.09.2011

Comet Garradd continues to brighten as it drifts across the northern sky. Last week the comet, visible with binoculars and discernable by its green coma, passed nearly in front of globular cluster M71.

Hartley 2 Star Cluster Tour
2.12.2010

Early in November, small but active Comet Hartley 2 (103/P Hartley) became the fifth comet imaged close-up by a spacecraft from planet Earth. Continuing its own tour of the solar system with a 6 year orbital period, Hartley 2 is now appearing in the nautical constellation Puppis.

NGC 4302 and NGC 4298
21.04.2017

Seen edge-on, spiral galaxy NGC 4302 (left) lies about 55 million light-years away in the well-groomed constellation Coma Berenices. A member of the large Virgo Galaxy Cluster, it spans some 87,000 light-years, a little smaller than our own Milky Way.

Comet NEAT and the Beehive Cluster
17.06.2004

To the unaided eye, they appeared as similar fuzzy patches. But when a bright comet passed in front of a bright star cluster last month, binoculars and cameras were able to show off their marked differences in dramatic fashion.

The Hunter, the Bull, and Lovejoy
13.01.2015

Heading north, Comet Lovejoy (C/2014 Q2) is putting on its best show for comet watchers now, with moonlight absent from mid-January's early evening skies. An easy binocular target and just visible to the unaided eye from dark sites, the comet sweeps across the constellation Taurus the Bull in this deep night skyscape.

Comet Garradd and M92
4.02.2012

Sweeping slowly through the constellation Hercules, Comet Garradd (C2009/P1) passed with about 0.5 degrees of globular star cluster M92 on February 3. Captured here in its latest Messier moment, the steady performer remains just below naked-eye visibility with a central coma comparable in brightness to the dense, well-known star cluster.

Encke and the Tadpoles
27.10.2023

History's second known periodic comet is Comet Encke (2P/Encke). As it swings through the inner Solar System, Encke's orbit takes it from an aphelion, its greatest distance from the Sun, inside the orbit of Jupiter to a perihelion just inside the orbit of Mercury.