Thursday, July 17, 2025

The Ellensburg, WA sky for the week of July 19, 2025

Saturday: As of July 17, both the US Senate and House of Representatives have rejected the White House NASA budget cuts and propose to keep NASA’s budget nearly unchanged. But your favorite NASA mission isn’t out of danger yet. Because of the White House request, NASA has directed teams to start submitting project termination plans. One of the missions in danger is the Deep Space Climate Observer (DSCOVR), a collaboration between NASA, NOAA, and the U.S. Air Force. Since reaching orbit in 2015, it has been Earth’s primary warning system for dangerous solar magnetic storms.

Sunday: Take a two and a half hour walk today. Too long, you say? 56 years ago today, Neil Armstrong and Buzz Aldrin took the first ever walk by humans on another world. They spend two and a half hours setting up scientific instruments and collecting rocks for study back on Earth. Their colleague Michael Collins orbited the Moon in the spacecraft the astronauts would use to return to Earth. While everyone seems to know about Armstrong and Aldrin, spend some time learning more about Collins by reading https://time.com/5624528/michael-collins-apollo-11/.

Monday: At 4:30 a.m., Venus is one and a half fists above the eastern horizon, right below the moon. Jupiter is a half a fist above the east-northeastern horizon.

Tuesday: Mars is a little more than one fist above the western horizon at 9:30 p.m.

Wednesday: Zubenelgenubi, the second brightest star in the constellation Libra. The name means "southern claw", a holdover from the time when this part of the sky was associated with the neighboring constellation of Scorpius the scorpion. Zubenelgenubi is a binary star system, easily seen with binoculars as a white and yellow pair. To a person living on a planet orbiting the dimmer of the two stars, the brighter star would be nearly as bright as the full Moon appears from Earth. Zubenelgenubi is one and a half fists above due southwest at 10:45 p.m.

Thursday: What you see with the naked eye isn’t all that can be seen. While astronomers can learn a lot from observing the sky in the visible wavelengths, many celestial objects radiate more light, and more information, in wavelengths such as radio, microwave, infrared, ultraviolet, x-ray, and gamma ray. In 2012, NASA launched the Wide-field Infrared Survey Explorer (WISE) to study objects that radiate in the infrared range such as asteroids, cool dim stars, and luminous galaxies. For an interesting comparison of how different wavelengths show distinct aspects of celestial objects, go to http://goo.gl/nvuax. If it weren’t for infrared telescopes such as WISE, astronomers would not know about the significant amount of dust in galaxies. We also wouldn’t know how much brighter than the Sun red supergiant stars are. Antares is a red supergiant star, currently sitting at one and a half fists above the southern horizon at 9:30 p.m. In the visible wavelengths, Antares shines 10,000 times brighter than the Sun. But since Antares is much cooler than the Sun, its energy distribution peaks in the infrared. Across all wavelengths of light, Antares shines 60,000 times brighter than the Sun. The JWST is also an infrared telescope.

Friday: Capella is the fourth brightest star we can see in Ellensburg. It is the brightest northerly star. Actually two stars, a binary star system of two yellow giant stars that orbit each other every 100 days. At 11:30 p.m., Capella is a half a fist above the northern horizon. At this time, the planet Saturn is half a fist above the eastern horizon.

The positional information in this column about stars and planets is typically accurate for the entire week. For up-to-date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm. All times are Pacific Time unless noted.

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