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Ephemeris: 12/24/2025 – Taking our weekly look at the whereabouts of the naked-eye planets
This is Ephemeris for Christmas Eve, Wednesday, December 24th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:06, and it will rise tomorrow at 8:18. The Moon, 3 days before first quarter, will set at 9:51 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 southwestern sky as soon as it gets dark. In a telescope Saturn sports a very thin ring, eight tenths of a degree from being edge on and slowly opening. Jupiter will rise at 6:26 PM in the east-northeast, below Castor and Pollux, the bright stars of Gemini. The giant planet is slowly moving westward with its retrograde motion. Jupiter’s 4 brightest moons can be seen even in binoculars, and shift position night to night. In the morning sky, only Jupiter can be seen, descending in the western sky. It will leave the morning sky, officially on January 10th, as it reaches opposition to the Sun.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
A note about transits of Jovian moons: A transiting moon is extremely difficult to pick up, however the moon’s shadow falling on the planet is much more easily spotted.
Ephemeris: 12/18/2025 – Orion and Scorpius
This is Ephemeris for Thursday, December 18th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:03, and it will rise tomorrow at 8:16. The Moon, 1 day before new, will rise at 8:22 tomorrow morning.
The wonderful constellation of Orion the hard luck hunter is seen rising in the east as twilight fades. According to one Greek myth he was killed by the sting of a giant scorpion, thus he can only rise after the summer constellation of Scorpius the scorpion sets in the southwest, and he must set as the scorpion rises on early spring evenings. By 9 pm, he is located in the southeast. His three belt stars are nearly vertically arranged in a line and equally spaced. They point down to the horizon, at the brightest nighttime star Sirius which rose 13 minutes before. The belt stars lie within a large rectangle of stars tilted to the left. His shoulders and knees. The top left star is the bright red Betelgeuse. The bottom right star is blue-white Rigel.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 12/17/2025 – Taking our weekly look at the whereabouts of the naked-eye planets
This is Ephemeris for Wednesday, December 17th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:03, and it will rise tomorrow at 8:15. The Moon, 2 days before new, will rise at 7:26 tomorrow morning.
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, six tenths of a degree from being edge on and slowly opening. In a couple of months the rings will be much more visible in telescopes. Jupiter will rise at 7:02 PM in the east-northeast, below 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. In the morning sky, Mercury just might be spotted very low in the east-southeast by 7:30. The next opportunity to spot Mercury will be in the evening in mid-February.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 12/16/2025 – Finding Orion and the Wintermaker
This is Ephemeris for Tuesday, December 16th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:03, and it will rise tomorrow at 8:14. The Moon, 3 days before new, will rise at 6:19 tomorrow morning.
In the east, the central winter constellation Orion the hunter throws a leg over the horizon around 7 PM as Robert Frost told in his poem Star-Splitter. The upright rectangle that is his body is tilted to the left as he rises on December evenings. A bright red star, Betelgeuse, is at the top left of the rectangle, his shoulder. At the opposite corner is blue-white Rigel, a knee. In the center of the rectangle is a line of three stars nearly vertically aligned as he rises, which represents his belt. The stars of Orion’s belt are how many folks can find him. The Anishinaabe native peoples of this area call him the Wintermaker whose arms are held wide to encompass the winter stars. His rising in the evening heralds the coming of winter, five days from now.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 12/15/2025 – Capella, the winter star that never quite leaves us*
This is Ephemeris for Monday, December 15th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:02, and it will rise tomorrow at 8:14. The Moon, halfway from last quarter to new, will rise at 5:13 tomorrow morning.
Capella is the northernmost first magnitude stars. Tonight it shines in the northeastern sky. First magnitude stars are the 21 brightest stars in the night sky. Capella is the 6th brightest. Although I’ve always known it as the little she-goat, Capella’s name literally translates to “little goat.” Her three Kids are represented by a narrow triangle of stars positioned to the right of her in tonight’s evening sky. Capella is in the topmost corner of the pentagonal constellation of Auriga the Charioteer. Capella is actually a system of four stars only 43 light years away. And never sets for listeners in the Interlochen Public Radio transmission area who have a low northern horizon.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
* If you live north of 44° north latitude.
Addendum
Ephemeris: 12/12/2025 – The most active meteor shower of the year will peak Sunday morning
This is Ephemeris for Friday, December 12th. Today the Sun will be up for 8 hours and 51 minutes, setting at 5:02, and it will rise tomorrow at 8:11. The Moon, 1 day past last quarter, will rise at 1:58 tomorrow morning.
We are ramping up to the most active meteor shower of the year, the Geminid meteor shower. And it has been getting more active over the years. The peak will be about 2 AM Sunday morning with a 30% Moon rising shortly after 3. The radiant is the point in space where the meteors seem to come from, which is near the star Castor in the constellation Gemini from which the shower gets its name. Unlike most meteor showers, the Geminids will be visible all night. The meteors will be seen all over the sky, but they all can be traced back to the radiant. The body responsible for this meteor shower is an asteroid rather than a comet with the name 3200 Phaethon, which comes very close to the Sun.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 12/11/25 – The constellation of the guy with the goats
This is Ephemeris for Thursday, December 11th. Today the Sun will be up for 8 hours and 51 minutes, setting at 5:02, and it will rise tomorrow at 8:11. The Moon, at last quarter today, will rise at 12:53 tomorrow morning.
The first constellation of winter is in the northeastern sky, called Auriga the charioteer. It’s to the upper left of Orion and directly left of Taurus. Auriga actually never really quite leaves us, because its brightest star, Capella is the star that never leaves us even in the heat of summer, Though for most of us it’s in the trees in the north. Auriga is a pentagon of stars with the Capella on top. Just right of Capella is a thin triangle of three faint stars, an asterism or informal constellation called the Kids, baby goats. Capella is their mother. For some reason they are all held by a charioteer, who is shown without his chariot. Ptolemy, last of the great Greek astronomers called Auriga the coachman. If so, he did have room for the goats.
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
Ephemeris: 12/10/2025 – Taking a look at the whereabouts of the naked-eye planets
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
Ephemeris: 12/09/2025 – Aldebaran, the “Follower”
This is Ephemeris for Tuesday, December 9th. Today the Sun will be up for 8 hours and 53 minutes, setting at 5:02, and it will rise tomorrow at 8:09. The Moon, 2 days before last quarter, will rise at 10:34 this evening.
Tonight will be the night of the earliest sunset of the year. For the last few nights the Sun has been setting within the same minute. Soon the Sun will set noticeably later.
The bright star Aldebaran appears at the lower left tip of a letter V group of stars laying on it’s side, the Hyades star cluster and the face of Taurus the Bull. It’s in the east in the evening, above Orion. Aldebaran isn’t actually part of the group. The cluster is about 153 light years away, while Aldebaran is 65. The star has an orange hue because its surface is cooler than the Sun’s. However, Aldebaran is 44 times larger in diameter, and shines 425 times brighter than the Sun. The name Aldebaran means “Follower” because it follows the Pleiades star cluster across the sky.
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
Ephemeris: 12/08/2025 – Hyades, half sisters of the Pleiades
This is Ephemeris for Monday, December 8th. Today the Sun will be up for 8 hours and 54 minutes, setting at 5:02, and it will rise tomorrow at 8:08. The Moon, 3 days before last quarter, will rise at 9:19 this evening.
At 8 o’clock this evening the constellation of Orion the hunter is still in the act of rising with one leg still stuck in the snow. What is above him is the constellation of Taurus the bull. His face is a letter V of stars or as a letter A, is the star cluster called the Hyades. In Greek myth the stars are the half sisters of the Pleiades, which are right above them. The Hyades star cluster is very special. They don’t look as splashy as the Pleiades which are younger and still have their hot blue white stars. However, the Hyades are much closer, a third as far as the Pleiades. In fact they’re close enough to be measured by trigonometry using Earth’s orbit as the base of a triangle, before satellites. Which was critical in measuring distances beyond the solar system.
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
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