The most detailed printed star atlas ever produced.  Considered the definitive reference set for stargazers, comprised of 1,548 sky charts based on the European Space Agency's Hipparchos and Tycho satellite survey catalogs.  One million stars and ten thousand nonstellar objects charted.  The scale of the charts matches the view at the focus of an 8-inch f/10 Schmidt-Cassegrain telescope. 

Some of the other information charted includes 250 of the brightest quasars, star magnitudes (based on printed image size), distance labels for stars within 200 light-years of the Sun, proper motion arrows for stars with motion exceeding 0.2 arcsec/yr, variable star amplitude and variability type, double stars have marks indicating separation and position angle, and more.  Incredibly information dense reference work.

6 clear acetate overlays to measure numerous positional data.

These volumes are in like new condition, no damage/defects/markings anywhere.  The binding and covers are library/reference quality.  Sturdy slipcase houses the 20 pound work.  Published by Sky Publishing who also publishes Sky and Telescope magazine. It is a beautiful example that the printed reference will endure and be appreciated long into the future.