Popular Astronomy, Volumes 24-25; Volume 1917

American amount Androm appear Association astronomical atmosphere Aurigae body bright Cassiop central Cephei Class cluster color comet comparison correction Cygni determined direction distance Draconis earth eclipse Ephemeris fact Figure Gemin given gives Herculis indicate interest July June latitude less light lines Lyrae magnitude March marked Mars mass matter mean measures meteor miles month moon motion nearly nebula night NOTES objects observations Observatory obtained Ophiuchi orbit parallax period Persei photographic planet plates position possible present probably Professor record region rotation scale seems seen Society solar spectra spectrum standard surface taken Tauri telescope theory universe VARIABLE STAR Virginis visible