Welcome to the University of Texas Skywatchers Report for Monday May 18th through Sunday May 31st.

The moon will be a very thin waxing crescent on Monday the 18th and then will reach first quarter on Saturday the 23rd. After that, we’ll have a waxing gibbous moon until it reaches full early in the morning of Sunday the 31st. This will be the second full moon in the month of May, which is now commonly known as a Blue Moon. This full moon is within a day of apogee, the Moon’s farthest point from the Earth in its orbit, so it will have the smallest angular size of any full moon in 2026.

Mercury is emerging from solar conjunction into the western skies shortly after sunset and will be setting an hour and a half after the sun by the end of the month.

Venus will continue to appear higher in the west each evening after sunset and is setting at 10:50 p.m. in mid-May and at 11:05 p.m. by the end of the month. Look for a very thin crescent moon alongside Venus on the evening of Monday the 18th.

Jupiter is also in the west at sunset and is appearing lower each evening, moving closer to Venus. Jupiter is setting at 12:20 a.m. mid-month and 11:30 p.m. at the end of May. Look for Jupiter below the crescent moon on the evening of the 20th.

In the morning skies, Saturn is rising at 4:20 a.m. in mid-May and at 3:35 a.m. by the end of May. Mars follows at 5:10 a.m. mid-month and 4:45 a.m. at the end of the month.

In space anniversaries for the second half of May, Saturday May 30th marks 55 years since the launch of Mariner 9, which became the first mission to orbit the planet Mars. Mariner 9 arrived at the Red Planet in November 1971 where it operated in orbit for almost a year and mapped 85% of the planet before it was decommissioned in late October 1972. Mariner 9 is also the namesake of the Valles Marineris canyon on Mars, which was discovered by that mission.

There will be no public viewing this summer on the UT campus telescopes so we can do maintenance and repairs. We expect to resume the regular viewing schedule in the Fall 2026 semester.

While you’re waiting for Austin-area telescope viewing to resume, you can tune in to McDonald Observatory live streams from west Texas. You can view past events on the McDonald Observatory YouTube channel and you can follow the observatory on social media and at McDonaldObservatory.org to be notified of future events.

Thank you for calling the University of Texas Skywatchers Report.