Burnham's Celestial Handbook Quotes

“the Horsehead must be classed as one of the most difficult objects in the sky. Barnard could find no definite sign of it with the 40-inch Yerkes refractor in 1913,”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“The hydrogen reaction operates most efficiently at the center of a star, where the temperature and pressure are greatest. Eventually, the hydrogen supply becomes depleted in this region, and the star develops a “core” of helium. The hydrogen reaction must then operate in a zone surrounding the core. As the core grows in mass, the hydrogen zone slowly increases in radius. This evolution is slow at first, but proceeds more and more rapidly as time goes on. When about 10% of the star’s mass has gone into the helium core, the star has evolved from the original point “A” on the diagram to the point “B”. By the time the point “C” is reached, the core contains 20% of the mass of the star. The increase in size and luminosity has become noticeable, and the star can now be classified as a subgiant. As more and more helium is added to the core, the outer regions continue to expand and the star follows the evolutionary path to point “D” where approximately 30% of the mass is contained in the core. Now, although the expansion lowers the star’s surface temperature, the increase in size more than compensates for this, and the total radiation therefore increases vastly as the evolution proceeds. When the star arrives at point “E” the diameter has increased by a factor of several hundred, and the luminosity is about 1000 times the original value. The star is now a typical red giant.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“The interesting and valuable fact about the cluster variables is that they all seem to be nearly equal in actual luminosity, regardless of the length of the period.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“The music of the Lyre, in Greek legend, cast such a spell that Orpheus charmed every living creature with it, even persuading the grim guardians of the Underworld to allow him to rescue his beautiful wife Eurydice from the Land of the Dead. Having been warned to cast no glance upon her until the couple had safely reached the upper world, Orpheus unfortunately lost Eurydice at the last moment by disobeying the fateful order. The story is one of the most popular of the Greek legends, and was the subject of the opera Orpheo ed Euridice by Gluck in 1762, and a ballet by Stravinsky in 1947.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“Another mystery concerns the fact that this white star has so often been described as “greenish” or “pale emerald”. Olcott refers to it as “the only naked-eyel star that is green in color”, while T.W.Webb refers to its “beautiful pale green hue”.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“DELTA GEMINORUM and PLUTO. The new planet (arrow) is shown here shortly after discovery at Lowell Observatory, in February 1930. Date of Photograph is March 4, 1930.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“There is no doubt that the Veil is expanding into a dusty region and sweeping up the interstellar material as it does so. The sky within the loop is noticeably clearer than the area outside, as evidenced by the difference in the number of faint stars visible in the two regions. This effect is plainly seen on the photograph on page 802”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“M85 (NGC 4382) Position 12228nl828. One of the bright members of the Virgo Galaxy Cluster, the great aggregation of external systems which is centered some 5° to the south. The chief facts concerning this very remarkable cluster are given in the constellation section on Virgo; the most notable members lying north of the border in Coma are: M85, M88, M98, M99, M100, and NGC 4565.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“It consists of a brilliant nucleus about 2’ in diameter, surrounded by a dusky halo of light that gives it a glittering gem-like appearance. The background is dark but glimpses of numerous, faint stars can be obtained in clear conditions.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System

“Sir William Herschel, with his great reflector, spoke of M53 as “one of J the most beautiful sights I remember to have seen in the heavens.”
― Robert Burnham Jr., Burnham's Celestial Handbook, Volume Two: An Observer's Guide to the Universe Beyond the Solar System