Skywatcher's Guide: October-December 2023

Just before sunrise, the Moon completes the third quarter of its orbit around Earth and begins the last quarter, appearing nearly overhead against the stars of Gemini the Twins.

New Moon at 10:55 am PT. The first very thin visible crescent after new is difficult to see, usually obscured by the glare of sunset, but it's theoretically observable from South America on the 15th (also from Central America and Southern Africa under perfect conditions). This observation marks the start of Rabi al Thani, the fourth month of the Islamic lunar calendar

An annular solar eclipse is visible along a narrow path crossing much of the Americas. More in Highlights.

Peak of the annual Orionid meteor shower. At its peak, the shower produces about 10-20 meteors per hour under perfect conditions, but how good are conditions this year? A run-down of coming major showers is in Highlights.

The Moon is at first quarter, visible in the south at nightfall, nestled between the stars of Sagittarius the Archer and Capricornus the Sea-Goat.

This month's full Moon is first to follow the Harvest Moon of September 29, and by tradition is known as the Hunter's Moon from the Algonquin, since prey is easier to find in the freshly-shorn fields. Also called the Blackberry Moon (Choctaw), and Falling Leaves Time (Nez Perce).

Partial lunar eclipse visible in Europe, Asia, Australia, Africa, North America, much of South America, Pacific, Atlantic, Indian Ocean, Arctic, Antarctica. More in Highlights.

The last quarter Moon occurs on the night of the 4th-5th, rising against the faint stars of Cancer the Crab and located high in the south at dawn.

Daylight Time ends at 2 am on the first Sunday in November in most of the US, as we turn clocks back one hour and the 1-2 am hour repeats—but our return to Standard Time (and Solar Mean Time) is short-lived, lasting only 4 months and ending on March 10, 2024. Where is Daylight Time not observed? Find out in Highlights.

New Moon at 1:26 am PT, starting a new lunation, or cycle of phases. Visual sighting of the first crescent marks the start of the fifth month of the Islamic calendar, Jumada al Awwal. This always-challenging observation is possible for sharp-eyed observers in the southern US, Central and South America, and throughout most of Africa just after sunset on the 14th.

The lack of moonlight makes it easier to observe the distant planet Uranus, which is at opposition and at its brightest. Viewing advice and a finder chart can be found at https://lovethenightsky.com/see-uranus-through-a-telescope. At least binoculars are needed—look about halfway between Jupiter and the Pleiades star cluster and about 2° south of a line joining them for a tiny, steadily shining disk with a greenish tint.

Peak of the Leonid meteor shower, which is active November 6-30, when Earth passes through the dust trail of Comet Tempel-Tuttle. Its peak coincides with a waxing crescent Moon that sets early, so observers in dark locations can expect about 15 meteors per hour. Advice on how to watch a shower is in Highlights.

The Moon reaches the first quarter during the early morning hours, when it's below the horizon. The next time we see it is when it rises at midday, around 1 pm

The full Moon rises at sunset, also known as the Beaver Moon (Algonquin), the Bison Moon (Natchez), and variations of the Frost or Frosty Moon (Choctaw, Creek, Assiniboine, Potawatomi, among others).

The Moon is at last quarter, rising late tonight against the stars of Leo the Lion.

New Moon at 3:31 pm PT, though not visible in the Sun's glare. Sighting of the first crescent after new marks the start of Jumada al Thani, the sixth month in the Islamic calendar. This difficult observation is possible from South America just after sunset on the 13th, and more easily from the rest of the world on the 14th.

Peak of the Geminid meteor shower, which is active December 6-19. This has become the most reliable display of the year and can produce as many as 80-100 meteors per hour under ideal conditions. Observing tips are in Highlights.

The first quarter Moon is at 10:39 am PT.

December solstice at 7:28 pm PT. This is the day the Sun rises and sets farthest south over the northern hemisphere, following its lowest arc across the sky and producing the shortest daylight period and longest night.

Peak of the Ursid meteor shower, just four days before a full Moon, so moonlight may obscure most of the meteors until the Moon sets. More details are in the meteor shower listing in Highlights.

Indigenous Americans called the full Moon nearest the winter solstice the Long Night's Moon (Algonquin), Time of Cold (Mohawk), and the Moon of the Popping Trees (Lakota Sioux and Arapaho)—names appropriate for the short, cold days and long nights which occur at this time of the year in the northern hemisphere.