Bakersfield Night Sky — January 18, 2025
Bakersfield College starts back up this coming week and the spring slate of evening shows at the William M Thomas Planetarium will be posted this week but we already have the Mesmerica shows lined up for the first Fridays and Saturdays in February, March, and April. The Mesmerica tickets will be sold through the Mesmerica website and tickets for the other Planetarium shows will be sold through Vallitix.
This past week Mars was at opposition as Earth passed by it in our faster, inner orbit. Mars is still very bright and will continue to be so for the rest of the month. Because we’ve been moving past by Mars, Mars has been appearing to move backward (retrograde) among the stars of Cancer and Gemini. It will continue doing that until late February.
Because Mars is closest to us of the outer planets, its retrograde loop on our sky is the largest, going from the middle of Cancer to the middle of Gemini. Tonight, you’ll see the bright orange-red planet next to the bright star Pollux of Gemini. Mars will be closest to Pollux on the night of January 22, getting to within about two thumb widths at arm’s length. Pollux is a KO-type giant star, meaning it is a dying star about nine times the diameter of the sun and about one thousand degrees cooler on the surface. It also means that Pollux has an orange-reddish tint to it that is similar to Mars but because Mars is so much brighter, we have an easier time seeing Mars’ color with the naked eye.
The color receptors in our eyes (the “cones”) require a lot of light while the other receptors (the “rods”) work just fine with less light. This is why most stars to the naked eye appear white while a few especially bright ones have a definite color tint to them. Look at Mars and Pollux with binoculars and you’ll probably be able to see Pollux’s color and compare it to Mars. They’ll both fit within the same field of your binoculars until the end of the month. Images made with extended exposure times are also able to collect more of the color, so those night shots can look a bit more colorful that what see with our eyes alone. Longer exposures also bring out objects too faint to see with our eyes alone, adding to the sparkle of the night shots.
Brilliant Jupiter ends its retrograde motion in the first week of February. It is now at the top of Taurus’ head in the south, appearing almost directly above orange-red Aldebaran at the eye of Taurus. Almost directly right of Jupiter will be the Pleiades star cluster. Low in the west we’ve seen Venus pass by Saturn. Yesterday and tonight they are at their closest separation—like Mars and Pollux mentioned above, about two thumb widths apart. Venus is almost 200 times brighter than Saturn. Saturn will be to the left of Venus. All of the outer planets and Venus will be above the horizon from sunset to a bit after 8:30 p.m., at which time Venus and Saturn will set or be buried in the usual haze layer.
Tonight the moon is a waning gibbous, rising about 10:30 p.m. On the night of January 20/21, a smaller waning gibbous moon (one day shy of last quarter phase) will rise about 12:30 a.m. trailing close behind Virgo’s brightest star, Spica. The moon will be at new phase on January 29, so at the very end of the month, you might be able to spot a thin sliver of the waxing crescent moon low in the west shortly after sunset just below Saturn, only a thumb width apart.
A couple of space science missions I did not include in my previous column’s rundown of space science launches in 2025 is the launch of SPHEREx and PUNCH in late February. They are both launching together on the same rocket and both have acronyms for shorthand names because the full names are more than a mouthful. SPHEREx stands for “Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer” and it will provide the first all-sky spectral survey, getting color data on over 450 million galaxies and over 100 million stars in our galaxy, the Milky Way. SPHEREx will collect data in 102 colors in the infrared to help us figure out how the universe’s expansion in the first pico-second after the Big Bang led to the structure of galaxy clusters we see today; help us understand the formation of galaxies; and measure the abundance of frozen water, carbon dioxide, and other essential ingredients for life in 9 million unique directions across the galaxy. SPHEREx’s prime mission is 25 months long.
PUNCH stands for “Polarimeter to Unify the Corona and Heliosphere”. It is a constellation of four small satellites that will make global, 3D observations of the sun’s corona (upper atmosphere) to help us figure out how the million miles-per-hour stream of charged particles— the “solar wind”—is produced. That is all part of enabling us to predict “space weather”, which affects the multi-billion dollar satellite network on which our multi-trillion dollar economy relies, as well as, ensure the stability of our power grid.
I hope that you’ll be able to find a time and place sometime in 2025 to gaze up in wonder at a dark night sky filled with thousands of stars.
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Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com
