Salpeter E W Edwin Walter (1 results)

Paperback. Condition: Very Good. 16 b/w photograhic plates, each with three sections of the spectrum. (illustrator). 1st Edition. stapled blue printed wraps; 8 clean, unmarked pages; with 16 photographic plates (loose); both in a quatro-folded slipcase; lite sunning but very little wear mostly of which is at the seams/hinges of the slipcase; owner's name on slipcase and booklet. a landmark spectral atlas and catalog published by the Vatican Observatory detailing the atomic emission wavelengths (measured in Angströms, of the element thorium. It serves as a highly accurate, universal reference standard for calibrating astronomical spectrographs and laboratory equipment. Because thorium is mono-isotopic and avoids complex hyperfine line splitting, its spectrum produces clean reference points critical for precise astronomical radial velocity and exoplanet searches.