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Ephemeris: 12/19/2025 – Winter begins Sunday
This is Ephemeris for Friday, December 19th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:04, and it will rise tomorrow at 8:16. The Moon is new today, and won’t be visible.
The thermometer and snowfall tell us that winter ought to be here. Well, it will be at 10:03 Sunday morning. At that point, the winter solstice, the Sun will be directly over the Tropic of Capricorn at 23 ½ degrees south latitude. It’s an odd name because 2,000 years ago the Sun was in indeed entering Capricornus. Now it will be entering Sagittarius, right above the spout of the teapot asterism we know so well in summer. From then on the Sun will be climbing up the sky each noon until June 21st next year when summer will start. To which I say: Go Sun Go! The Sun will almost make it up to 22 degrees above the southern horizon at local noon, which is 12:40 pm, in Interlochen and be out for only 8 hours and 48 minutes. If it stayed that low all year, we’d be in a deep freeze, possibly colder than Antarctica.
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: 12/20/2024 – Winter is coming tomorrow!
Dec 20. This is Bob Moler with Ephemeris for Friday, December 20th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:04, and it will rise tomorrow at 8:17. The Moon, 2 days before last quarter, will rise at 10:55 this evening.
Today is the last full day of autumn. Tomorrow at 4:40 a.m. winter will begin as the Sun passes the winter solstice and stops its southward movement in the sky. Immediately it will slowly climb northward again. It will lengthen the daytime hours and increase the power of the Sun as it gets higher in our sky. The cooling of the Northern Hemisphere will continue until late January, on average, until the lengthening days and increased solar altitude will finally overcome it. Ancient cultures weren’t all that sure that the Sun would come back, since they didn’t understand what was really happening. So when the solstice finally arrived it was a time for great celebrations which survive to this day.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.
Addendum
Ephemeris: 12/21/2023 – Winter comes late this evening
This is Bob Moler with Ephemeris for Thursday, December 21st. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:04, and it will rise tomorrow at 8:17. The Moon, 2 days past first quarter, will set at 3:37 tomorrow morning.
Today is mostly the last day of Fall, since the moment of solstice will arrive at 10:28 pm (03:28 on the 22nd UTC). If you’re south of the equator this is the first day of summer. The Earth reaches a point in its orbit where its North Pole is tipped its furthest away from the Sun, and is in shadow in the middle of its six-month night. The Sun for us is up only 8 hours, 48 minutes, and to boot the Sun only rises 22 degrees above the horizon giving us the least amount of energy of any day of the year. Why did the ancients celebrate this time of year? That’s because the Sun had slowed and stopped its drift southward and was beginning to come back higher in the sky. Spring and summer would eventually return!
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.
Addendum
12/22/2020 – Ephemeris – Winter is going to be colder before it starts to warm up in a little over a month
This is Ephemeris for Tuesday, December 22nd. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:05, and it will rise tomorrow at 8:18. The Moon, 1 day past first quarter, will set at 1:47 tomorrow morning.
Now that winter is here, it’s going to get snowier and colder even though the amount of heat the Northern Hemisphere gets from the Sun bottomed out yesterday. There are two consequences of the Earth’s axial tilt with regard to the Sun on the winter solstice. First, the Sun is only up 8 hours 48 minutes. Second at its highest at local noon the Sun is so low, only 22 degrees above the horizon around here that its heat is spread out over a greater area so is diluted to only 40% of the peak heat we get from the Sun at noon on the summer solstice. And on the summer solstice the Sun stays up almost six and three-quarters of an hour longer. Even though it doesn’t feel like it at our latitude winter is 4 days shorter than summer. You’ll find out why in less than two weeks.
Addendum
Comparing the sun’s path at the summer and winter solstices. This is a stereographic representation of the whole sky which distorts the sky and magnifies the size of the sun’s path near the horizon.
Earth’s position at the solstices and equinoxes. This is an not to scale oblique look at the Earth’s orbit, which is nearly circular. The Earth is actually farthest from the Sun on July 4th. Click on the image to enlarge. Credit: ESO (European Southern Observatory which explains the captions in German and English.
12/18/2020 – Ephemeris – Winter begins Monday morning
This is Ephemeris for Friday, 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, 3 days before first quarter, will set at 9:29 this evening.
Monday will host two astronomical events. The second will be the extremely close conjunction or appearing together of the planets Jupiter and Saturn, which I’ll talk about then. But first, at 5:02 Monday morning winter will begin with the winter or December solstice. The word solstice means Sun stand still. On or about December 21st, the Sun appears to stop moving southward measured at noon and will begin moving northward again. All this is the result of the Earth’s 23 ½ degree axial tilt and our motion around the Sun. Our area of the globe is now receiving less energy from the Sun to support our temperatures, and they will continue to fall for the next month or so even as the Sun rises higher and stays out longer.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The sun’s daily path through the sky from horizon to horizon on the first day of winter, the winter solstice. Credit My LookingUp program.
12/22/2015 – Ephemeris – Welcome to winter, or summer if you’re down under
Ephemeris for Tuesday, December 22nd. The Sun will rise at 8:17. It’ll be up for 8 hours and 48 minutes, setting at 5:05. The Moon, 3 days before full, will set at 5:59 tomorrow morning.
Today is the first full day of winter. For folks south of the equator this is the first full day of summer. The Earth reached a point in its orbit where its north pole is tipped its furthest away from the Sun, and is in shadow in the middle of it’s six month night. We do see the Sun, though less than 9 hours of daylight, and to boot the Sun only rises 22 degrees above the horizon giving us the least amount of energy of any day of the year. Why did the ancients celebrate this time of year? That’s because the Sun had slowed and stopped its drift southward and was beginning to come back higher in the sky. They still had to go through the worst of winter, but the Sun was coming back. Spring and summer would eventually return!
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comparing the sun’s path at the summer and winter solstices. This is a stereographic representation of the whole sky which distorts the sky and magnifies the size of the sun’s path near the horizon.
The above chart shows the diurnal path of the Sun at the winter and summer solstices for Traverse City, MI near 45º north latitude. Peak Sun altitude at noon at the winter solstice is 22º, while it’s 69º at the summer solstice.
12/21/2015 – Ephemeris – Except for 12 minutes today is the last day of autumn.
Ephemeris for Monday, December 21st. The Sun will rise at 8:16. It’ll be up for 8 hours and 48 minutes, setting at 5:04. The Moon, 3 days past first quarter, will set at 4:50 tomorrow morning.
Here we are at the mostly last day of autumn. The last 12 minutes will be the start of winter. The winter solstice will occur at 11:48 this evening, here in the Eastern Standard Time Zone. Next year winter will start 18 hours earlier. The reason is that next year is a leap year and the addition of an extra day will push all the solstices and equinoxes back by about 18 hours. Why only 18 hours? 18 hours is three-quarters of a day, and by this time next year we will have used up a quarter of that adjustment already. The Earth takes approximately 365 and a quarter days to orbit the Sun, so a day is added every 4th year, except century years not divisible by 400. I’ll discuss more about the implications of the solstice tomorrow.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Not quite the solstice, this is the Earth on December 16th, 2015 taken by the EPIC camera on the DISCOVR spacecraft at the Sun-Earth L1 point, some 1.5 million miles (1 million km) from the Earth. Credit: NOAA.
12/01/2015 – Ephemeris – Previewing December skies
Ephemeris for Tuesday, December 1st. The Sun will rise at 7:59. It’ll be up for 9 hours and 4 minutes, setting at 5:03. The Moon, 2 days before last quarter, will rise at 11:13 this evening.
December is the month with the shortest daylight hours. Winter will officially arrive at the winter solstice on the 21st at 11:48 p.m. There will be little movement in the sunset times: In the Traverse City/Interlochen area this will be from 5:03 tonight, down to 5:02 and then advancing to 5:11 at the end of the month. There is more movement in the sunrise times which will advance from 7:59 today to 8:20 on the 31st. There is also little movement of daylight hours. The noontime sun will hang around 22 to 23 degrees above the southern horizon all month. We have some great events this month, from an occultation of Venus by the moon on the 7th, to the Geminid meteors on the 14th and Comet Catalina will be seen in binoculars on mornings all this month.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
Star Chart for December 2015. Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 9 p.m. EST. That is chart time. Note, Traverse City is located 45 minutes behind our time meridian. To duplicate the star positions on a planisphere you may have to set it to 45 minutes earlier than the current time.
Evening astronomical twilight ends at 6:48 p.m. EST on December 1st, decreasing a minute 9 days later before increasing to 6:57 p.m. EST on the 31st.
Morning astronomical twilight starts at 6:15 a.m. EST on December 1st, and increasing to 6:34 a.m. EST on the 31st.
Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.
For a list of constellation names to go with the abbreviations click here.
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
- The Summer Triangle is still up and is shown in red.
- GemR is the Geminid meteor shower radiant
Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Daylight Time. Some additions made to aid clarity.
Date Local Event
Time EST
Dec 01 Tu Venus: 43.3° W 03 Th 2:41am Last Quarter 04 Fr 1:21am Moon-Jupiter: 2° N 04 Fr 1:33pm Moon Ascending Node 05 Sa 9:56am Moon Apogee: 404800 km 05 Sa 9:40pm Moon-Mars: 0.1° N - Occultation ** 07 Mo 11:55am Moon-Venus: 0.7° S - Occultation * 11 Fr 5:29am New Moon 12 Sa 3:15am Moon South Dec.: 18.4° S 14 Mo 12:48pm Geminid Shower: ZHR = 120 17 Th 9:32pm Saturn-Antares: 6.2° N 18 Fr 10:13am Moon Descending Node 18 Fr 10:14am First Quarter 21 Mo 3:53am Moon Perigee: 368400 km 21 Mo 11:48pm Winter Solstice 22 Tu 9:00pm Ursid Shower: ZHR = 10 23 We 9:16pm Mars-Spica: 3.5° N 23 We 2:09pm Moon-Aldebaran: 0.7° S 25 Fr 2:30am Moon North Dec.: 18.4° N 25 Fr 6:11am Full Moon 28 Mo 9:59pm Mercury Elongation: 19.7° E 29 Tu 3:30pm Moon-Regulus: 2.9° N 31 Th 12:55pm Moon-Jupiter: 1.6° N 31 Th 3:19am Moon Ascending Node Jan 01 Fr Venus: 37.9° W
* The occultation will be visible in the US, except extreme southwestern Alaska and Hawai’i; and Canada down to Panama. In the Grand Traverse area of Michigan the occultation starts around 12:20 p.m. and ends around 1:27 p.m. This is a daytime event for most of the US. Note that the actual time depends on your exact location. I’ll have more information in a non Ephemeris post on Saturday the 5th. The Occultation map is here.
** On December the 5th there will be an occultation of Mars visible across the Indian Ocean and much of Australia. That occultation map is here.
Estimating occultation timings for your location
I used Cartes du Ciel the free software that I have a link to on the right. Make sure that the program is set for topocentric positions under Setup/Solar System. And you have entered your position under Setup/Observatory. You can find your location in Google Earth, or your GPS device or smart phone.
You can also use Stellarium. Just make sure the Moon is normal sized.
In both programs you can lock the Moon or Aldebaran in the center of the screen Pick a time in advance of the occultation and using the set time window walk the star towards the Moon, mark the time. Then walk the star out from the Moon and record the reappearance time. That’s it.
This should work with other planetarium programs too.
For better accuracy go to the International Occultation Timing Association (IOTA) website. Download and install their Occult4 program for Windows computers. Follow the instructions. When I ran the program for my location, the location I use for Interlochen/Traverse City (Since I live approximately half-way between the two). I got results within a half-minute of the IOTA Occult4 program results. So the approximation method using planetarium programs is valid.
Comet C/2013 US10 (Catalina)
This comet has been hiding for the last two years after its discovery, moving into the far southern hemisphere of the sky. However this month it has emerged into our morning sky. This comet is a one time visitor from the Oort Cloud to the inner solar system and will be ejected into interstellar space. It passed perihelion on November 15th, coming just inside the Earth’s orbit on the other side of the Sun from us. It’s orbit will be headed northward and a bit toward us, so it will keep its brightness steady.
The position marks in the chart have the date and the magnitude. However the comet is currently appearing one magnitude dimmer than shown. So instead of appearing as nearly 5th magnitude, it will really be 6th magnitude. It’s definitely a binocular or telescopic object.
According to the brightness graph the comet began to under perform in brightness back in September, however, according to a new brightness formula the comet may increase in brightness by a magnitude by late February when it will be well placed for viewing all night. To monitor the brightness reports from observers go to http://www.aerith.net/comet/catalog/2013US10/2013US10.html.
The tracks of Comet C/2013 US10 (Catalina) for December 2015 along with part of Venus’ track. Created using Cartes du Ciel (Sky Charts).
12/20/2013 – Ephemeris – Winter begins tomorow
Ephemeris for Friday, December 20th. The sun will rise at 8:15. It’ll be up for 8 hours and 48 minutes, setting at 5:04. The moon, 3 days past full, will rise at 8:32 this evening.
The thermometer and snowfall tell us that winter ought to be here. Well it will be at 12:11 p.m. (17:11 UT) tomorrow afternoon. At that point the sun will be directly over the Tropic of Capricorn at 23 ½ degrees south latitude. Odd name because 2,000 years ago the sun was in indeed entering Capricornus. Now it’s entering in Sagittarius, right above the spout of the teapot asterism we know so well in summer. From then on the sun will be climbing up the sky each noon until June 21st next year when summer will start. To which I say Go Sun Go! The sun will barely make it to 22 degrees above the southern horizon at local noon in Interlochen and be out for only 8 hours and 48 minutes. If it stayed there all year we’d be in a deep freeze colder than Antarctica.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Sun’s view of the Earth at the instant of winter solstice. Created using Celestia.
06/20/2013 – Ephemeris – Summer starts tomorrow
Ephemeris for Thursday, June 20th. Today the sun will be up for 15 hours and 33 minutes, setting at 9:31. The moon, 3 days before full, will set at 4:15 tomorrow morning. Tomorrow the sun will rise at 5:57.
Summer will arrive overnight at 1:04 a.m. tomorrow morning when the sun will reach its highest point in the northern sky. If you were watching the sun’s shadow of a flag pole at local noon, when the sun is due south, it would be getting shorter every day since the winter solstice back on December 21st. From tomorrow until the next winter solstice that shadow will be getting longer. We are getting the most heat from the sun now due to the length of daylight and the high altitude of the sun most of the day. Because the earth and water takes time to heat up, we are not experiencing our greatest temperatures yet. That will take a month or a month and a half. That’s why solstice just starts summer and is not at the peak of it.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comparison of shadows between winter and summer solstices. Note the angles are approximate.
Bob Moler's Ephemeris Blog 