... 2001 April 16 . The Hydra Cluster of Galaxies . ... Explanation: The Hydra Cluster of Galaxies contains well over 100 bright galaxies - but perhaps fewer galaxies than might be expected from its mass. ... Most of a cluster's mass , however, appears to be in a form too dark to see , as analyses of the distribution of X-ray light , gravitational lensing , and internal motions indicate. ... The Hydra Cluster of Galaxies, named for its home constellation , spans about ten million light years . ...

... December 13, 1997 . The Coma Cluster of Galaxies . ... The Coma Cluster of Galaxies pictured is one of the densest clusters known - it contains thousands of galaxies . Each of these galaxies house billions of stars - just as our own Milky Way Galaxy does. ... In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! Most galaxies in Coma and other clusters are ellipticals , while most galaxies outside of clusters are spirals . ...

Supernova 2002bu in NGC 4242 . This page is devoted to information on Supernova 2002bu in NGC 4242 Basic information on this SN, including the last reported brightness, on this Supernova can be found on the main page . Information on the original web pages for many of these images can be found on the updates and links web pages. This is a type IIn supernova found in a galaxy which is in Canes Venatici. ... Mag . ... 2002/03/28.26 . ... A Leroy image . ... SUPERNOVA 2002bu IN NGC 4242 . ...

ABSOLUTE PROPER MOTIONS OF 331 OPEN CLUSTERS . ... The proper motions of stars in the fields of 331 open clusters were taken from Four-Million Star Catalog (4M-catalog) of positions and proper motions (Volchkov et al. ... The absolute proper motions for 21 young open clusters have been derived by comparison of precise relative proper motions of individual stars and their corresponding absolute proper motions. ... Sign of proper motions in RA . ... 0.0001 arcsec/yr . ... rms error in RA proper motion . ...

... We have compiled the Catalogue of extragalactic supernovae using the GCVS card catalogue. ... Doubtful (?), or rejected (-) SN 8 A1 --- RemFlag [*] The '*' indicates a remark in sn_rem.dat 10- 19 A10 --- Gal Parent galaxy designation 21- 22 I2 h RAh Right Ascension 1950 of Parent galaxy 23- 24 I2 min RAm Right Ascension 1950 (minutes) 25- 28 F4.1 s RAs Right Ascension 1950 (seconds) 29 A1 --- DE- Declination 1950 (sign) 30- 31 I2 deg DEd Declination 1950 of Parent ...

... The distance scales of the objects are matched both by comparing the first derivatives of the angular velocity determined separately from radial velocities and proper motions and by the statistical-parallax method. ... Good agreement between the inferred 0 and our calculations based on space velocities suggests that the Lindblad relation holds throughout the entire sample volume. ... Brandt and Blitz (1993) published the distances and radial velocities for a total of 206 H II-regions. ... Astron. ...