Special to CosmicTribune.com, December 4, 2023, 2023

Excerpts from weekly Sky&Telescope report.

MONDAY, DECEMBER 4

■ Last-quarter Moon tonight (exact at 12:49 a.m. EST). The Moon rises around 11 or midnight local time. By the time Tuesday’s dawn begins to break the Moon is high in the south.

TUESDAY, DECEMBER 5

■ At this time of year the Big Dipper lies down lowest soon after dark, due north. If you’re as far south as Miami, it’s entirely below the north horizon.

But by midnight the Dipper stands straight up on its handle in fine view in the northeast, while Cassiopeia has wheeled down to the northwest to stand nearly upright on the bright end of its W shape.

WEDNESDAY, DECEMBER 6

■ Jupiter’s moon Io crosses onto Jupiter’s face at 6:47 p.m. EST, moving from celestial east to west, followed by its tiny black shadow at 7:36 p.m. EST. They depart Jupiter’s western limb at 8:56 and 9:46 p.m. EST, respectively. Meanwhile, Jupiter’s Great Red Spot crosses the planet’s central meridian around 9:26 p.m. EST.

THURSDAY, DECEMBER 7

■ Earliest sunset of the year (if you’re near latitude 40° north). By the time of the solstice and longest night on December 21st, the Sun actually sets 3 minutes later than it does now. And the latest sunrise doesn’t come until Jan. 5. These slight discrepancies arise from the tilt of Earth’s axis and the ellipticity of Earth’s orbit.

■ The Pleiades and Aldebaran below them are well up in the east after dark. So you know Orion can’t be far behind below them. Orion’s whole main figure, formed by his seven brightest stars, takes about 1 hour 20 minutes to clear the horizon. By 8 or 9 p.m. Orion is up in fine view.

■ Before and during early dawn Friday morning the 8th, look southeast for the waning crescent Moon. Spot Spica, magnitude +1.0, a couple degrees below it, as shown here, before the sky gets too bright.

The waning Moon in the dawn advances from Spica to Venus over the course of 24 hours. In the last six days, the gap between the two points has widened from 5° to 11°.

FRIDAY, DECEMBER 8

■ M31, the Andromeda Galaxy, passes your zenith sometime around 7 or 8 p.m. if you live in the world’s mid-northern latitudes. The exact time depends on how far east or west you live in your time zone.

■ Before and during dawn Saturday morning the 9th, catch the lovely meetup in the eastern sky of Venus and the thin crescent Moon.

SATURDAY, DECEMBER 9

■ Orion is coming into good view low in the east-southeast after dinnertime now. And that means Gemini is also coming up to its left (for the world’s mid-northern latitudes).

SUNDAY, DECEMBER 10

■ The Cassiopeia W hangs very high in the northeast after dark. The bottom star of the W is Epsilon (ε) Cassiopeiae, the faintest. That’s your starting point for hunting down the little-known star cluster Collinder 463: sparse, loose, subtle, but visible in large binoculars and wide-field scopes on these moonless nights. It’s 8° to Epsilon’s celestial north (the direction toward Polaris), surrounded by a nice quadrilateral of 4th- and 5th-magnitude stars about 3° wide. The cluster is nearly 1° long, curved and narrow. Its brightest stars are only 8th and 9th magnitude, so use averted vision.