Administration/ESA Double Star mission operated alongside Cluster II from 2004 to 2007. The first of the satellites of Cluster II to re-enter the atmosphere did so on 8...

1012 solar masses each. Each has its own system of satellite galaxies: The Andromeda Galaxy's satellite system consists of Messier 32 (M32), Messier 110...

gravitationally bound to the Sun. While most satellite galaxies are dwarf galaxies, satellite galaxies of large galaxy clusters can be much more massive. The Milky...

each other, thus they are not a star cluster, a fact established by measurements taken by the Hipparcos satellite in 1997. An additional 30 or so much...

active galactic nucleus. Galaxies can also have satellites in the form of dwarf galaxies and globular clusters. The constituents of a galaxy are formed out...

on 4 June 1996. It carried the Cluster spacecraft, a constellation of four European Space Agency research satellites. The launch ended in failure due...

three formations possible: trailing, cluster, and constellation. Trailing formations are formed by multiple satellites orbiting on the same path. Each one...

Berenices cluster, etc.). Measurements of the distance have elicited much controversy. Results prior to the launch of the Hipparcos satellite generally...

Star clusters are large groups of stars held together by self-gravitation. Two main types of star clusters can be distinguished. Globular clusters are...

quasars Satellite galaxies List of satellite galaxies of the Milky Way List of Andromeda's satellite galaxies List of Triangulum's suspected satellite galaxies...

An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the...

as part of the Milky Way subgroup, which is part of the local galaxy cluster, the Local Group. There are 61 small galaxies confirmed to be within 420...

Caldwell 50 or the Satellite Cluster) is an open cluster in the Rosette Nebula, which is located in the constellation Monoceros. This cluster has several O-type...

A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center...

known as ASTRO-H and New X-ray Telescope (NeXT), was an X-ray astronomy satellite commissioned by the Japan Aerospace Exploration Agency (JAXA) for studying...

consisted of two satellites: an Equatorial satellite (TC-1) and Polar satellite (TC-2). Double Star followed in the footsteps of ESA's Cluster mission by studying...

using the Hipparcos satellite and the Hubble Space Telescope. An alternative method of computing the distance is to fit the cluster members to a standardized...

use inter-satellite communication. Satellite constellations should not be confused with: satellite clusters, which are groups of satellites moving very...

Filton) for four Cluster satellites, which were destroyed on 4 June 1996 on the Ariane 5G, Flight 501 Technologies for Artemis satellite Ariel 6 AfriStar...

Pegasi. Earth-orbiting satellites Uhuru and Chandra X-ray Observatory have detected two bright X-ray sources in this cluster: Messier 15 X-1 (4U 2129+12)...

two brightest satellite galaxies, M32 and M110. An amateur telescope can reveal Andromeda's disk, some of its brightest globular clusters, dark dust lanes...

observatory satellite Uhuru close to the center of the Coma cluster and this source was suggested to be designated Coma X-1. The Coma cluster contains about...

Satellite Instructional Television Experiment or SITE was an experimental satellite communications project launched in India in 1975, designed jointly...

As built, the Condor Cluster was the 33rd largest supercomputer in the world and was used to analyze high definition satellite imagery at a cost of only...

The Quintuplet cluster is a dense cluster of massive young stars about 100 light years from the Galactic Center (GC). Its name comes from the fact it has...

hair. The Hipparcos satellite and infrared color-magnitude diagram fitting have been used to establish a distance to the cluster's center of approximately...

parsecs (330,000 light-years) from the Sun. This star cluster is further away than the SagDEG satellite galaxy. Initially it was thought to be a dwarf galaxy...

geolocation of Soviet Navy assets during the Cold War. NOSS involves satellite clusters operating in low Earth orbit to detect radar and other electronic...

Persei. The Hipparcos satellite and infrared color-magnitude diagram fitting have been used to establish a distance to the cluster of ~560 light-years (172 pc)...

(born 1964) is an American astronomer whose interests include galaxy clusters, satellite galaxies, and gravitational lensing. Educated in Canada and the US...