September 25
The Queen's Brightest
Sun Position
The Sun is in Libra at about -2° declination, south of the celestial equator and moving further south daily. The Northern Hemisphere is in the first days of astronomical autumn; evening darkness sets in noticeably earlier than two weeks ago.
Sky Highlight
Cassiopeia is circumpolar for observers north of about 30°N and climbs to a prime position high in the north by late October evenings; from mid-northern latitudes in late September, it is already well up by 10 PM. No major meteor shower peaks today.
Deep Sky Object
NGC 663, open Cluster, Cassiopeia. About 6,900 light-years away, this moderately rich open cluster contains roughly 80 members and sits in a dense section of the Milky Way arm. Circumpolar for Northern Hemisphere observers north of 40°N; very low or not visible from southern latitudes.
Featured Star
Schedar (α Cas) is a cool orange giant of spectral type K0IIIa, about 228 light-years away, the brightest star in Cassiopeia by conventional visual magnitude. Its orange color is subtle but detectable with the naked eye, driven by a surface temperature of about 4,500 K, well below the Sun's 5,780 K.
Around This Date
- September 25, 1973The crew of Skylab 3 (Bean, Garriott, Lousma) splashed down after 59 days in orbit, setting a then-record for human spaceflight duration and returning extensive solar observation data.
- September 26, 1983Soviet officer Stanislav Petrov declined to report what the early-warning system indicated were five incoming US missiles, correctly judging the alerts to be a satellite error, a decision that may have prevented nuclear escalation.
Schedar's orange hue is quieter than red giants tend to be in descriptions, but point a binocular at it and the warmth is real.