October 31
The Monster's Breath
Sun Position
The Sun is in Scorpius near -18.5° declination. This is one of the dates farthest from any solstice or equinox by about 45 days, the cross-quarter point, midway between the September equinox and December solstice. Day and night length differences are near their most rapid rate of change.
Sky Highlight
October 31 is a traditional cross-quarter day, approximately midway between the autumn equinox and winter solstice in the Northern Hemisphere (and between spring equinox and summer solstice in the Southern Hemisphere). The Southern Taurid meteor shower is near its most active phase, and the Taurus region rises in the east after dark, with the Pleiades and Hyades both visible by late evening. The Orionids, now past their peak, still contribute occasional meteors.
Deep Sky Object
M1 (Crab Nebula), a supernova remnant about 6,500 light-years away. M1 in Taurus is the remnant of a supernova observed by Chinese and Arab astronomers in 1054 CE, the expanding debris cloud is still growing at roughly 1,500 km/s and is powered by a pulsar at its center spinning 30 times per second, one of the fastest and best-studied neutron stars known. Accessible from both hemispheres as Taurus rises in October; best visibility from Northern Hemisphere and southern mid-latitudes.
Featured Star
Menkar (α Cet) is a red giant (M1.5IIIa) about 249 light-years away, the alpha star of a sea monster constellation, burning at the expanded, reddened stage that precedes stellar death on million-year timescales. On the last night of October, Cetus rides high in the south for Northern Hemisphere observers, and Menkar is the brightest reference point in a dim, sprawling figure. Menkar, the nostril of the sea monster, a red giant fading toward its end.
Around This Date
- October 31, 1992The Vatican formally acknowledged that the Inquisition's judgment against Galileo in 1633 had been an error, issuing a statement that rehabilitated his astronomical work 359 years after his condemnation.
- October 30, 1981The Soviet Venera 13 spacecraft launched toward Venus, carrying instruments that would transmit color photographs of the Venusian surface (the first ever) for 127 minutes after landing in March 1982.
October ends at a cross-quarter point, midway between equinox and solstice, the sky is neither at rest nor at an extreme, just moving steadily toward both.