September 6
Pulse in the Square
Sun Position
The Sun is in Virgo near +5° declination. Dusk is arriving earlier each evening at northern latitudes; southern spring is solidly underway.
Sky Highlight
The epsilon Perseids, a minor shower active in early-to-mid September, peak around this period with a modest zenithal hourly rate of roughly 5. The radiant is in Perseus, best placed for Northern Hemisphere observers in the hours before dawn.
Deep Sky Object
M31, Andromeda Galaxy. About 2.5 million light-years away, M31 is the nearest large spiral galaxy to our own and spans more than three full moon-widths across the sky, though only the bright core is visible to the naked eye. It is rising in the northeast after dark for Northern Hemisphere observers; Southern Hemisphere viewers see it low in the north.
Featured Star
Scheat (β Peg) is a pulsating red giant (spectral type M2.5II-III) about 196 light-years distant, varying in brightness over a roughly 38-day cycle as its outer layers expand and contract. It glows with the subdued orange-red hue characteristic of cool, giant stars much larger than the Sun.
Around This Date
- September 6, 2006The Heliospheric Imager on the STEREO-A spacecraft returned its first images of the solar wind structure, inaugurating a new era of three-dimensional solar weather monitoring.
- September 6, 2013The first Minotaur V rocket launched from Wallops Island, Virginia, carrying NASA's LADEE spacecraft to study the lunar exosphere and dust environment.
Scheat's slow pulse is too gradual for any single night to show, but knowing it is there changes how you look at what seems like a fixed point.