This is Ephemeris for Wednesday, December 10th. Today the Sun will be up for 8 hours and 52 minutes, setting at 5:02, and it will rise tomorrow at 8:10. The Moon, 1 day before last quarter, will rise at 11:45 this evening.
Let’s take our weekly look at the whereabouts of the naked-eye planets. Saturn is the brightest star-like object in the southern sky as soon as it gets dark. In a telescope Saturn sports a very thin ring, half a degree from being edge on and slowly opening. Normally, I’d say that Saturn’s rings are easy to see in a telescope. In a couple of months the rings will be much more visible in telescopes. Jupiter will rise at 7:29 PM in the east-northeast, beneath Castor and Pollux, the bright stars of Gemini. Jupiter’s 4 brightest moons can be seen even in binoculars, and shift position night to night. Tonight they will all be in line on one side of the planet. Mercury might be spotted very low in the east-southeast by 7 AM tomorrow morning.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Jupiter and Saturn along with the zodiacal constellations in this panorama at 9 PM tonight, December 10, 2025. Created using Stellarium.
Mercury (though not as bright as this) and the last quarter Moon, as they might appear at 7 AM tomorrow morning, December 11, 2025. Created using Stellarium.
The Moon, at last quarter, as seen tomorrow morning, December 10, 2025. A view visible in small telescopes showing an image with and without selected features labeled. Created using Stellarium, LibreOffice Draw, and GIMP.
Telescopic Saturn, and Jupiter (north up) as they would be seen in a small telescope with the same magnification at 9 PM tonight, December 10, 2025, Saturn will be 17.7″ in diameter, but its rings, being nearly edge on, may show up brighter than seen here, and extend to 41.3″. They are tilted 0.5° from being edge on. Jupiter will be 45.2″ in diameter. Mercury appears too small to be shown here, but its apparent diameter will be 6.2″ and appears 72% illuminated. The (”) symbol means seconds of arc, or 1/3600th of a degree. Created using Cartes du Ciel (Sky Charts), LibreOffice Draw and GIMP.
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on December 10th, 2025. The night ends on the left with sunrise on the 11th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
This is a low precision ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, December 10th and 11th, 2025. Some of the columns are self-explanatory, others are not. The transit column is the time that the body crosses the meridian and is due south. Elong, for elongation, is the angle between the Sun and that body. RA is right ascension, which is the object’s east-west position on the celestial sphere in hours and minutes. Dec is declination which is the north-south position of the object on the celestial sphere in degrees and minutes. R is the distance of that object from the Sun in astronomical units. An astronomical unit is about 93 million miles or 150 million kilometers. And Delta is the distance of that object from the Earth, also in astronomical units. I omit the ‘m’ in am and pm for compactness. The data was generated using my LookingUp for DOS app and displayed as a table by my Ephemeris Helper app.
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