October 2
The Queen's Knee
Sun Position
The Sun is in Libra at roughly -4° declination, tracking south of the equator. Northern Hemisphere days are shortening with purpose now; Southern Hemisphere afternoons are growing longer.
Sky Highlight
Cassiopeia transits near the zenith for mid-northern latitudes in October evenings, making this a prime month to explore the rich Milky Way fields surrounding the W. Southern Hemisphere observers see Cassiopeia skimming the northern horizon or not at all.
Deep Sky Object
NGC 457, an open cluster (the Owl Cluster or ET Cluster) about 7,900 light-years away. NGC 457 in Cassiopeia is a young, bright open cluster whose two brightest members mark what many observers see as the eyes of an owl, or, more recently, the silhouette of the film character E.T., arms outstretched. Best for Northern Hemisphere observers in autumn; from southern latitudes it is low or inaccessible.
Featured Star
Ruchbah (δ Cas) is a white giant (spectral class A5III) about 99 light-years away, one of the five named stars that form Cassiopeia's distinctive W shape as seen from Earth. The name comes from the Arabic for knee, marking the queen's seated posture in the old sky charts. Ruchbah, the queen's knee, one of the five stars in Cassiopeia's W.
Around This Date
- October 2, 1935The Hayden Planetarium opened in New York City, becoming one of the most influential public astronomy institutions in the United States and a primary site of popular science education for decades.
- October 4, 1957The Soviet Union launched Sputnik 1, the first artificial Earth satellite, inaugurating the space age and triggering an immediate global reckoning with what orbit meant for science and security.
Cassiopeia climbs highest in October nights, a useful anchor when Orion has not yet risen.