12/13/2021 – Ephemeris – The Geminid Meteor Shower reaches its peak tomorrow morning

This is Ephemeris for Monday, December 13th. Today the Sun will be up for 8 hours and 50 minutes, setting at 5:02, and it will rise tomorrow at 8:12. The Moon, 3 days past first quarter, will set at 3:41 tomorrow morning.

Tomorrow morning we will have the chance to see near the peak of the Geminid meteor shower after the Moon sets. Some of its members can be seen tonight, in the bright moonlight. This shower is currently besting the Perseid meteor shower of August, with a predicted 120 meteors per hour tomorrow morning. The problems for us in viewing this fabulous shower, beside the bright Moon this year, are the cold temperatures and usually cloudy skies. The source of the Geminids was discovered in 1983. It is a probably burnt out comet with the asteroid designation 3200 Phaethon, which swoops down to only 13 million miles of the Sun. Some call it a rock comet. The Geminids were first seen in 1862.

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

An all sky view at 4 am, December 14th, 2021, showing the radiant for the Geminid meteor shower. The meteors will be seen all over the sky. Their trails, however, can be traced back to their radiant. The radiant is marked on the chart as GemR, near the star Castor in Gemini. The sky at that hour is that of the evening sky of early spring. Created using my LookingUp program.

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.
• Follow the arc of the handle of the Big Dipper to the star Arcturus, then
• Follow the spike to Spica.

12/11/2020 – Ephemeris – More on the Geminid meteor shower peaking this weekend

This is Ephemeris for Friday, 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, 3 days before new, will rise at 5:33 tomorrow morning.

This weekend and specifically Sunday evening to Monday morning the Geminid meteor shower will be at its peak, with up to 120 meteors appearing an hour in the early morning hours of Monday. The meteors will appear to come from near the star Castor, the northernmost star of the constellation of Gemini the twins. Castor and Pollux are the namesake stars at the head of Gemini. While they will seem to come from a specific point in the sky, they will be seen all over the sky, and be traced back to the point. They are coming in on parallel trajectories, just as straight railroad tracks recede to a point in the distance. Let’s hope for clear skies. The meteor shower lasts all night.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Star Chart for 7 pm, or about 2 hours after sunset. December 13, 2020. Click on image to enlarge. GemR is the location of the Geminid radiant low in the northeast. Click on image to enlarge. Created using my LookingUp program.

All sky chart of the Geminid Radiant 1 am Dec 14, 2020. GemR is the location of the Geminid radiant nearly overhead in the southeast. 

All sky chart of the Geminid Radiant 6 am Dec 14, 2020. GemR is the location of the Geminid radiant in the west.

12/10/2020 – Ephemeris – The Geminid meteor shower will reach its peak Sunday evening and Monday Morning December 13/14, 2020

This is Bob Moler with Ephemeris for Thursday, December 10th. Today the Sun will be up for 8 hours and 52 minutes, setting at 5:02 pm which will signal the beginning of the Jewish feast of Chanukah. Sunrise tomorrow will be at 8:10 am. The Moon, 3 days past last quarter, will rise at 4:13 tomorrow morning.

The Geminid meteor shower, the most active meteor shower of the year will be at its most active Sunday night and Monday morning. This year the Moon will be new on Monday and won’t interfere. Our problem is that it’s December, one of the cloudiest months of the year. The Geminid meteors will seem to come from near the star Castor, the second brightest star in Gemini. The actual source of the meteors is the asteroid or rock comet Phaethon. If it is an asteroid it comes closest to the Sun of any asteroid. It has been observed by spacecraft shedding dust when it’s heated near the Sun. It is probably a dead comet.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Star Chart for 7 pm, or about 2 hours after sunset. December 13, 2020. Click on image to enlarge. Click on image to enlarge. Created using my LookingUp program. 

All sky chart of the Geminid Radiant 1 am, or about 7 hours after sunset, Dec 14, 2020. Click on image to enlarge.

All sky chart of the Geminid Radiant 6 am, or about 2 hours before sunrise, Dec 14, 2020. Click on image to enlarge.

12/13/2019 – Ephemeris – Tonight is the first night that straddles the peak of the Geminid meteor shower

Ephemeris for Friday, December 13th. Today the Sun will be up for 8 hours and 50 minutes, setting at 5:02, and it will rise tomorrow at 8:12. The Moon, 1 day past full, will rise at 6:33 this evening.

Tonight and tomorrow nights will straddle the peak of the Geminid meteor shower. It is the best meteor shower of the year and it is getting more active over the years. The Moon will interfere with all but the brightest meteors. 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. 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. It comes very close to the sun, So it may shed bits of itself due to heat stress. I suppose I can’t resist this: That’s how the asteroid crumbles.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

3200 Phaethon a rock comet showing a tail as it nears the Sun. Credit NASA/STEREO

Eastern sky for Geminids at 10 p.m. December 13, 2019. On the 14th the Moon will be the same distance from Pollux but below it. Remember that the Geminid meteors will be seen all over the sky. It might help to hide the moon behind a building so as to better see the brighter meteors. Created using Stellarium.

Orbit of 3200 Phaethon with the Earth and Phaethon at 10:02 p.m. December 12, 2019. (03:02 UT Dec 13) Credit TheSkyLive.com.

Orbits of Fireballs on the night of December 13-14 as recorded by NASA’s All Sky Cameras six years ago. The preponderance of fireballs (bright meteors) are Geminids. These are published daily on Spaceweather.com. Credit: NASA and Spaceweather.com.

Eastern sky for Geminids at 10 p.m. December 13, 2019. On the 14th the Moon will be the same distance from Pollux but below it. Remember that the Geminid meteors will be seen all over the sky. It might help to hide the moon behind a building so as to better see the brighter meteors. Created using Stellarium.

From the International Meteor Organization: Observing proposal: Geminids and Full Moon

 

12/12/2019 – Ephemeris – Previewing the Geminids this weekend

Ephemeris for Thursday, 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, at full today, will rise at 5:38 this evening.

This upcoming weekend is the weekend of the greatest annual meteor shower of the year. They’re the Geminids. I confess to never having seen a Geminid. The reason is that it’s generally too cloudy, and for me too cold and this year is another problem, a bright Moon. In dark skies they have a 120 per hour peak, when the radiant point in Gemini is overhead. The body that was discovered to produce these meteors doesn’t appear to be a comet. It is designated as an asteroid 3200 Phaethon. Phaethon gets extremely close to the sun at 13 million miles (21 million km) and one of the STEREO Sun monitoring satellites caught it developing a tail when close to the Sun. Phaethon may then be the first known rock comet. I’ll have more on it tomorrow. (12/08/2014)

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Eastern sky for Geminids at 10 p.m. December 13, 2019. On the 14th the Moon will be the same distance from Pollux but below it. Remember that the Geminid meteors will be seen all over the sky. It might help to hide the moon behind a building so as to better see the brighter meteors. Created using Stellarium.

Orbits of Fireballs on the night of December 13-14 as recorded by NASA’s All Sky Cameras six years ago. The preponderance of fireballs in yellow (bright meteors) are Geminids. These are published daily on Spaceweather.com. Credit: NASA and Spaceweather.com

12/01/2014 – Ephemeris – Previewing December skies

Ephemeris for Monday, 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 past first quarter, will set at 3:32 tomorrow morning.

Let’s preview December’s skies.  Winter will officially arrive on the 21st at 6:03 p.m., the winter solstice.  The noontime sun will dip from 23 ½ degrees to a bit less than 22 degrees above the southern horizon on that day.  There will be little movement in the sunset times: In the Traverse City/Interlochen area this will be from 5:03 today, 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 this morning to 8:19 on the 31st.  The big event in December will be the Geminid meteor shower whose maximum is on the morning of the 14th.  But will be hampered by the moon after 12:17 a.m that morning.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Star Chart for December 2014. Created using my LookingUp program.

The Moon is not plotted.  The planets and stars are plotted for the 15th at 9 p.m.  That is chart time.

Evening astronomical twilight ends at 6:48 p.m. on December 1st, decreasing  one minute by the 9th and increasing to 6:57 p.m. on the 31st.

Morning astronomical twilight starts at 6:14 a.m. on December 1st, and increasing to 6:33 a.m. 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.

Also shown is the Summer Triangle in red. Clockwise from the top star is Deneb in Cygnus, Vega in  Lyra and Altair in Aquila.

The green pointer from the Big Dipper is:

• Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.

The Geminid radiant is shown in yellow and marked GemR.