... The spectrum of the brightest star, our Sun, shows several dark gaps perpendicular to the flow of it’s colours (figure 1). These so called spectral absorption lines where discovered in 1802 by the English scientist William Wollaston. ... Some stars as Pollux show a spectrum similar to that of our sun with strong Ca II and Fe II lines, others as Sirius or Vega show strong absorption lines of hydrogen, others, as Mira show very complicated spectra due to molecular absorption lines (see figure 5). ...

The Second U.S. Naval Observatory CCD Astrograph Catalog ( UCAC2 ) Table of Contents 1) Introduction 2) Summary of the Project a) Observations and Instrumentation b) Reductions of UCAC Observations c) Computation of Proper Motions 3) Properties of the Catalog and Important Notes For the User a) Sky Coverage b) Completeness c) Positions, Proper Motions and Error Calculations d) UCAC2 Magnitudes e) 2MASS Photometry f) Non-stellar ... All stars in the UCAC2 have proper motions. ...

The Database of Close Binary Systems . ... Team . ... This web-based interactive database is being developed and maintained by a team at the Sternberg Astronomical Institute of the Moscow State University . The project is an on-line extension of our catalogue on "Highly Evolved Close Binary Stars" (volumes I, II) published by Gordon and Breach in 1996. As of September 2009, the database (both the software and the content) is in its development/testing phase. ...