November 5
The Demon's Blink
Sun Position
The Sun is in Scorpius near -17° declination. Northern days are noticeably brief; Southern Hemisphere evenings stretch pleasantly.
Sky Highlight
The South Taurid meteor shower continues, and the North Taurids begin to pick up, together producing a combined rate of around 10–15 meteors per hour at their best. Taurid meteors are unusually slow (roughly 28 km/s) making them easy to follow across the sky. Both branches are visible from either hemisphere.
Deep Sky Object
M34, open cluster in Perseus, about 1,400 light-years away. A loose, well-resolved cluster of roughly 100 stars, easily swept with binoculars, with a handful of wide double stars visible in small telescopes. Best from northern latitudes, Perseus being a circumpolar constellation for much of the Northern Hemisphere in autumn.
Featured Star
Algol (β Persei) is an eclipsing binary 92.8 light-years away, a blue-white main-sequence star paired with an orange subgiant (spectral class B8V + K2IV), and every 2.87 days the dimmer companion passes in front, dropping Algol's brightness by nearly a full magnitude for roughly ten hours. The Arabs called it Ra's al-Ghul, the Demon's Head, and it was almost certainly the first variable star observed by human eyes.
Around This Date
- November 5, 1838Friedrich Bessel announced his parallax measurement of 61 Cygni, the first successfully measured stellar distance, placing that star about 10.3 light-years away.
- November 9, 1934Walter Baade and Fritz Zwicky proposed that supernovae produce neutron stars, a prediction not confirmed observationally until the Crab Nebula pulsar was discovered in 1968.
Watch Algol long enough and you will see it dim and recover, the sky's most reliable watcher of a star eating its companion's light.