Welcome to the University of Texas Skywatchers Report for Monday June 22nd through Sunday June 28th.
The moon was at first quarter late on Sunday the 21st and will reach full on Monday the 29th, so we’ll have a waxing gibbous moon all of this week.
Mercury is sinking back towards the sun after last week’s greatest elongation and is setting at 9:55 p.m. at midweek. Jupiter is just above Mercury and is setting at 10:15 p.m. Venus is above Jupiter and is setting at 11:10 p.m.
In the predawn skies, Saturn is rising at 2:00 a.m. and Mars rises a couple of hours later at 4:10 a.m.
In space anniversaries this week, Friday June 26th marks 30 years since the Galileo spacecraft made its first close flyby of Jupiter’s moon Ganymede, the largest moon in our solar system. The flyby was used as a gravity-assist to reduce the spacecraft’s orbital period, but the close approach was also used to conduct science on that moon. On this flyby, instruments on Galileo detected signs of a self-generated magnetosphere around Ganymede, the first, and to date only, one found for a moon in the solar system.
During Galileo’s nearly eight years in orbit around Jupiter, it made six close fly-bys of Ganymede, including the closest flyby to date of 164 miles above the moon’s surface. The Jupiter Icy Moons Explorer (or JUICE) launched in 2023 will become the first spacecraft to orbit Ganymede, which will occur in 2032.
There will be no public viewing this summer on 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.
