September 29
The Circumpolar Tip
Sun Position
The Sun is in Libra at about -5° declination. For Northern Hemisphere observers near 45°N latitude, nights are now about 13 hours long; Southern Hemisphere observers are experiencing symmetric spring conditions.
Sky Highlight
Cassiopeia is now above the pole and visible all night from latitudes north of about 30°N, making it the reliable background constellation for the entire autumn and winter observing season. No major meteor shower peaks today.
Deep Sky Object
NGC 869 / NGC 884, Double Cluster, Perseus. These two open clusters, each about 7,500 light-years away, are well-placed overhead for mid-northern observers by mid-evening and circumpolar from higher latitudes. They are among the sky's finest targets for binoculars or a low-power telescope eyepiece.
Featured Star
Caph (β Cas), the yellow-white Delta Scuti variable at spectral type F2III-IV and 54.7 light-years distance, marks the western tip of Cassiopeia's W and is the first point of the constellation to rise in the northeast. At 54.7 light-years, it is close enough that its distance is known to better than 1% precision from Hipparcos parallax measurements.
Around This Date
- September 29, 1988Space Shuttle Discovery launched on mission STS-26, the Return to Flight mission after the Challenger disaster, successfully deploying a NASA Tracking and Data Relay Satellite.
- September 29, 2008SpaceX's Falcon 1 became the first privately developed liquid-fueled rocket to reach Earth orbit, on its fourth launch attempt, marking the beginning of the commercial orbital launch era.
Caph rises in the northeast before the rest of the W clears the horizon, patient, a little early, as if it has somewhere to be.