Welcome to the University of Texas Skywatchers Report for Monday December 15 through Sunday December 21.

The new moon for the month of December is on Friday night into Saturday morning, so we’ll have a waning crescent moon in the pre-dawn skies for most of the week and then start into the waxing crescent phase late in the weekend.

Mars and Venus are both now just a couple of weeks away from solar conjunction and are lost in the sun’s glare.

Saturn is high in the south after sunset and is setting at 12:25 a.m. at midweek.

Jupiter is rising at 7:20 p.m. at midweek and then is visible for the rest of the night.

In the morning skies, Mercury is sinking back towards its next conjunction but is still rising an hour and 20 minutes before sunrise, so you might be able to get a glimpse of it if you have a good view to the east-southeast.

The winter solstice for the northern hemisphere occurs at 9:03 a.m. on Sunday December 21 in Austin when we will experience our lowest amount of daylight for the year at 10 hours and 11 minutes. Compare that to the 14 hours and 6 minutes we have at the summer solstice in June.

In space anniversaries this week, Tuesday December 16th marks 60 years since the launch of Pioneer 6, one of four identical spacecraft deployed to measure the space environment of the inner solar system. The spacecraft measured cosmic rays, the solar wind, the Sun’s magnetic field, and were the first space-based space weather network to monitor the effects of solar storms. Pioneer 6 collected data for at least 30 years and the last communications with the spacecraft were in December 2000 to celebrate its 35th anniversary. Although there hasn’t been any contact with the spacecraft in recent years, it’s thought to still be in orbit around the Sun between the orbits of Venus and Earth.

Public viewing on UT campus telescopes has finished for the fall 2025 semester. Spring semester viewing will resume in the second half of January 2026.

Thank you for calling the University of Texas Skywatchers Report.