August 3
The Eagle on the Wind
Sun Position
The Sun is in Leo at around +17° declination. Northern Hemisphere afternoons remain warm and long; Southern Hemisphere observers are gaining minutes of darkness each evening.
Sky Highlight
The Perseid meteor shower continues building; the radiant in Perseus rises higher after midnight for Northern Hemisphere observers, and rates are noticeably better than in late July. Southern Hemisphere observers can catch some activity, but the radiant stays low in the north.
Deep Sky Object
M11, the Wild Duck Cluster in Scutum, is at a favorable altitude in August evenings from mid-latitudes of both hemispheres. Roughly 6,200 light-years away, it is one of the richest and most compact open clusters in the sky, with around 3,000 stars packed into a region that looks almost globular at low magnification.
Featured Star
Altair, the alpha star of Aquila the Eagle, is an A7V main-sequence star just 16.7 light-years away (one of our nearest stellar neighbors) and it spins so fast, completing a rotation roughly every nine hours, that it is noticeably oblate, bulging at its equator. Light that left Altair tonight set out when you were a few years younger.
Around This Date
- August 3, 2004NASA's MESSENGER spacecraft launched from Cape Canaveral, beginning its long looping journey to Mercury for what would become the first orbital study of the innermost planet.
- August 5, 2011NASA's Juno spacecraft launched from Cape Canaveral on a five-year journey to Jupiter, where it would study the planet's atmosphere, magnetic field, and interior structure.
Altair spins fast enough that its own shape betrays it, a star that cannot hold still even from sixteen light-years away.