[STARGAZING] October 2017

One of two annual meteor showers associated with Halley’s famous comet will reach its peak in the hours before dawn on October 21st. This is the Orionid shower, named after the constellation of the legendary Hunter from which the meteors seem to stream. Under the dark skies of a rural wilderness, free from urban light pollution, you can expect to see meteors starting at midnight and increasing in strength to a rate of 20 or more per hour by 5:40 a.m. when the sky begins to brighten. Comet Halley orbits the sun every 75 or 76 years, and the Orionids are dusty fragments shed from its icy nucleus in past centuries. Comet Halley last visited the inner solar system in 1986. In 2023 it will reach the farthest point in its orbit from the sun (the comet’s aphelion) and will begin to fall back toward the sun, to which it will next draw near in the summer of 2061.

The ringed planet Saturn is the only bright evening planet, but it is becoming lower and lower in the sky on successive evenings, moving from the south-southwest to the west-southwest over the course of the month. Appearing similar to a bright golden star against the background of faint stars of Ophiuchus the Serpent-Bearer, Saturn has reached the end of its period of evening visibility for the year. A telescope is needed to see the planet’s spectacular system of rings. This month the ring system is tilted nearly 27 degrees to our line of sight, the maximum amount for the next 15 years.

The brilliant planet Venus is visible above the eastern horizon at dawn. On the 5th, it appears very close to the fainter but distinctly orange planet Mars.

The moon is full on the 5th, last quarter on the 12th, new on the 19th, and first quarter on the 27th. On the 15th, use binoculars to watch at 3:11 a.m. as the bright star Regulus, in the constellation Leo the Lion, suddenly pops into view after being hidden, or occulted, by the crescent moon. This observation will require a clear eastern horizon because the moon will only be four degrees high in the Los Angeles sky when Regulus reappears.

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