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06/02/2023 – Ephemeris – A South Pole adventure and a comet collision presentation – Tonight!

June 2, 2023 Leave a comment

This is Bob Moler with Ephemeris for Friday, June 2nd. Today the Sun will be up for 15 hours and 22 minutes, setting at 9:22, and it will rise tomorrow at 5:59. The Moon, 1 day before full, will set at 5:14 tomorrow morning.

An Antarctic Odyssey: Winter-Over at South Pole Station will be the presentation by John W. Briggs, via Zoom, at tonight’s meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers Observatory at 9 pm. John was a team member building a 24-inch infrared telescope and related experiments that were set up at the South Pole in time for him and colleagues to observe the July 1994, explosive crash of fragmented comet Shoemaker-Levy 9 into the planet Jupiter. There are two ways to attend: In person at the observatory, south of Traverse City on Birmley Road, or via Zoom with a link provided by the society’s website gtastro.org just prior to the meeting.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.

Addendum

Images of Jupiter in the infrared before and after Fragment C of Comet Shoemaker-Levy 9 struck Jupiter. The brightness reveals temperature of the atmosphere. Credit: University of Chicago.

About the Program

An Antarctic Odyssey: Winter-Over at South Pole Station

A presentation via Zoom by John W. Briggs

Abstract:
In a lavishly illustrated presentation, John W. Briggs of New Mexico will describe his year-long experience living at the Geographic South Pole while working for the Center for Astrophysical Research in Antarctica. In preparation for this at Yerkes Observatory of the University of Chicago, John was a team member building a 24-inch infrared telescope and related experiments that were set up at the Pole in time for him and colleagues to observe the July 1994, explosive crash of fragmented comet Shoemaker-Levy 9 into the planet Jupiter.

John weathered the “winter-over” with 26 other members of the U.S. Antarctic Program in an experience that many believe approximates what life will be like someday at a lunar or Martian outpost. Once begun, South Pole winter-over is an irreversible commitment, since the Program’s special LC-130 ski planes can’t land in the winter temperatures — in 1994, sometimes as low as 107 degrees F. below zero (with windchill, as low as -180 degrees). John will delight the audience with his perspective on the total South Pole experience — the strange natural environment, the odd social atmosphere, and the challenging, ongoing science.

01/27/2023 – Ephemeris – Where is comet ZTF this weekend?

January 27, 2023 Comments off
Here’s the next 4 nights of Comet ZTF. It is for 3 am on the dates posted, rather than moonset. Full moon is a coming, which will pretty much wipe out the comet. Then we can wait for dark skies once again. The tail rendering simply suggests the direction of the ion tail, blown away from the sun. Created using Cartes du Ciel (Sky Charts), labeled with LibreOffice Draw.

This is Ephemeris for Friday, January 27th. Today the Sun will be up for 9 hours and 36 minutes, setting at 5:44, and it will rise tomorrow at 8:06. The Moon, 1 day before first quarter, will set at 1:08 tomorrow morning. | Comet ZTF is now passing the star Kochab in the Little Dipper and is heading out to the barren wastes of Camelopardalis, the giraffe, which I’m sure not very many people have heard of because there’s no bright stars in it. The big question people have is why this comet was supposedly green. It is not particularly rare, even though the news reports I’ve seen of it and in social and main media seem to have intimated this. And they also say it comes around every 50,000 years or that it’s the only green comet and it comes every 50,000 years which is incorrect. There’s a certain amount of hype that comes with comets. They can be spectacular and they can be duds. I remember back in 1973 a large new comet was supposed to zip around the sun and be super bright called comet Kohoutek people my age might remember that. It was a pretty much dustless comet. I it’s the dust tail it really makes comets bright, not the ion tail of ionized gasses.

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.

01/26/2023 – Ephemeris – Where’s Comet ZTF tonight?

January 26, 2023 Comments off
Comet ZTF finder chart for 12:01 am, January 27, 2023, shortly after moonset (evening of the 26th). The tail rendering simply suggests the direction of the ion tail, blown away from the sun. Created using Cartes du Ciel (Sky Charts), labeled with LibreOffice Draw.

This is Bob Moler with Ephemeris for Friday, January 27th. Today the Sun will be up for 9 hours and 36 minutes, setting at 5:44, and it will rise tomorrow at 8:06. The Moon, 1 day before first quarter, will set at 1:08 tomorrow morning.

Comet ZTF is now passing the star Kochab in the Little Dipper and is heading out to the barren wastes of Camelopardalis, the giraffe, which I’m sure not very many people have heard of because there’s no bright stars in it. The big question people have is why this comet was supposedly green. It is not particularly rare, even though the news reports I’ve seen of it and in social and main media seem to have intimated this. And they also say it comes around every 50,000 years or that it’s the only green comet, which is incorrect. There’s a certain amount of hype that comes with comets. They can be spectacular, or they can be duds.

I remember back in 1973 a large new comet was supposed to zip around the sun and be super bright called Comet Kohoutek, people my age might remember that. It was a pretty much dustless comet. It’s the dust tail that really makes comets bright, not the ion tail of gasses. A few years later, Comet West came by for the Bicentennial in early 1976. As the comet came around the sun near perihelion, its solid nucleus started to break apart, liberating a vast dust tail. It was wonderful.

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.

This post is actually longer than I have time for the Ephemeris program (59 seconds). I created this speech to text, due to my current physical and mental problems, it’s more stream of consciousness than my normal writing. So if it still makes sense, I’ll leave it in.

01/23/2023 – Ephemeris – New “green” comet C/2022 E3 (ZTF)

January 23, 2023 Comments off

This is Bob Moler with Ephemeris for Monday, January 23rd. Today the Sun will be up for 9 hours and 27 minutes, setting at 5:38, and it will rise tomorrow at 8:10. The Moon, 2 days past new, will set at 8:05 this evening.

I’m sure that many of us have now heard of a bright new comet that’s supposed to be visible in our sky that’s green. One, it is a newly discovered comet from 9 months ago. Two, it is green. Three, it won’t look green to the eye. And four, it isn’t really that bright. One of the rules of I have in mentioning objects to observe on this program is that it has to be found with the naked eye. This comet does not meet that criteria. One could find it with binoculars when it’s near a bright star which it’s not tonight, so that’s one thing but in order to see it, it will probably look like a little fuzzy blob in a pair of binoculars. I’m not sure that the tail that would be visible. The observer has to wait until after the moon sets, because moonlight washes out a comet, big time.

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

Comet ZTF finder

Comet ZTF finder chart for 1/24/23 through 1/29/23 at 9 pm. Plotted daily at 9 pm EST, though the best time to spot the comet will be after moonset which will advance by about an hour a night. The plot of the comet’s tail simply suggests a direction and not the appearance of the tail. Created using Cartes du Ciel. (Sky Charts). The plots are marked with the month-day and expected magnitude or brightness. Magnitudes are like golf scores. The larger the number, the poorer the golfer, and the dimmer the celestial object is.

12/10/2021 – Ephemeris – Our last look at Comet Leonard before it leaves forever*

December 10, 2021 Comments off

This is Ephemeris for Friday, 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, at first quarter today, will set at 12:25 tomorrow morning.

This is the day of the earliest sunset of the year. It doesn’t coincide with the shortest day because the Earth is moving faster in its orbit than average and getting ahead of its rotation a bit. Comet Leonard’s last appearance in the morning sky is tomorrow or Sunday before twilight overwhelms it. At 6:30 am it will be just a bit south of due east at azimuth 93 degrees and an altitude of 9 degrees, a bit less than the width of a fist held at arm’s length. When it gets into the evening sky, its track will take will be along the horizon from the southwest to the south. It will come very close to Venus, and I suspect that is what will alter its orbit slightly, so it will never return and end up becoming an interstellar comet.

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.

* After this weekend, the comet will enter the evening sky, but will hang quite low to the horizon in evening twilight as it passes Venus, heads southward and fades. It would best be viewed by observers in the Southern Hemisphere. It’s headed out of the solar system in a hyperbolic orbit.

Addendum

Comet Leonard 7 am, 12/11/21

Comet Leonard (C/2021 A1) finder chart for 7:00 am, December 11, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 22.1 million miles away, and will come within 21.7 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard (C/2021 A1) in the morning

Comet Leonard’s positions at 7:15 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for December 10th. The star field will be shifting to the upper right each morning at 7:15 from the December 10th date at 7:15. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. Created using Cartes du Ciel (Sky Charts).

12/09/2021 – Ephemeris – Comet Leonard and the Oort Cloud

December 9, 2021 Comments off

This is Ephemeris for Thursday, 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, 1 day before first quarter, will set at 11:14 this evening.

Comet Leonard will only be available to be spotted for the next two mornings. After that, it will be too close to the direction of the Sun to be spotted. It came in from hundreds of times the Earth’s distance from the Sun from a spherical area around the solar system call the Oort cloud. This area, proposed as a source of comets, was named after Dutch astronomer, Jan Oort, who hypothesized its existence. Near as we can tell, Comet Leonard had been falling toward the Sun for 40,000 years. Tomorrow morning the comet will be nearly 30 degrees below and a bit left of the bright star Arcturus from 6:00 to 7 am tomorrow morning. 30 degrees is three times the width of one’s fist held at arm’s length.

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

Comet Leonard 6 am 12-10-21

Comet Leonard (C/2021 A1) finder chart for 6:00 am, December 10, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 23.1 million miles away, and will come within 21.7 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard (C/2021 A1) in the morning

Comet Leonard’s positions at 7:15 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for December 10th. The star field will be shifting to the upper right each morning at 7:15 from the December 10th date at 7:15. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. The tails shown here simply show the direction of the tail, which will be very short, if visible at all visually. Created using Cartes du Ciel (Sky Charts).

12/07/2021 – Ephemeris – This is the best week to view Comet Leonard

December 7, 2021 Comments off

This is Bob Moler with Ephemeris for Tuesday, December 7th. Today the Sun will be up for 8 hours and 55 minutes, setting at 5:02, and it will rise tomorrow at 8:07. The Moon, halfway from new to first quarter, will set at 8:43 this evening.

The evening sky between 5:45 and 7 pm will feature Venus, the crescent Moon, with dim Saturn above it and Jupiter all in the southwestern sky. Saturn will appear dim, only in the early part of that period, due to bright twilight. Saturn is about midway between Venus and Jupiter. In the morning sky, Comet Leonard continues to fall inward toward the Sun. It’s passing relatively close to the Earth, now about 29 million miles. It will pass its closest to on Sunday at about 21 million miles, at which time we’ll have a hard time spotting it in morning twilight. Comet Leonard will stay barely bright enough to spot in dark skies by really sharp-eyed observers without binoculars or a telescope. The rest of us will need optical aid.

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

Comet Leonard finder 12/08/21 6:30 am

Comet Leonard (C/2021 A1) finder chart for 6:30 am, December 8, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 26.7 million miles away, and will come within 21.7 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard (C/2021 A1) in the morning

Comet Leonard’s positions at 6:30 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for November 27th. The star field will be shifting to the upper right each morning at 6:30 from the November 27th date at 6:30. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. Created using Cartes du Ciel (Sky Charts). I’ve reversed the colors from previous printings of this image. Reprinted from my article in the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society.

12/06/2021 – Ephemeris – A new comet is reaching naked-eye or binocular visibility

December 6, 2021 Comments off

This is Ephemeris for Monday, December 6th. Today the Sun will be up for 8 hours and 56 minutes, setting at 5:02, and it will rise tomorrow at 8:06. The Moon, 2 days past new, will set at 7:27 this evening.

Comet 2021 A1, is also known as Comet Leonard, for its discoverer Gregory J. Leonard of the Mount Lemmon Survey, near Tuscon, Arizona. When it was found, on January 3rd this year, it was farther from the Sun than Jupiter. January 3rd of next year, less than a month from now, it will pass its closest to the Sun at a distance of around 57 million miles from the Sun. This is after falling in toward the Sun for the last 40,000 years. It will pass close to Venus, and its orbit will be tweaked to escape the solar system to eventually head out among the stars. Tomorrow morning it will be 7 ½ degrees or 3 fingers below left of Arcturus, the brightest star in the east before 6:30. It’s 5th magnitude, but still requires binoculars for most folks to be able to spot.

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

Comet Leonard finder 12/07/21 6:30 am

Comet Leonard (C/2021 A1) finder chart for 6:30 am, December 7, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 29 million miles away, and will come within 22 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard (C/2021 A1) in the morning

Comet Leonard’s positions at 6:30 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for November 27th. The star field will be shifting to the upper right each morning at 6:30 from the November 27th date at 6:30. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. The comet tails shown show the direction of the tail, if visible, only. Created using Cartes du Ciel (Sky Charts). I’ve reversed the colors from previous printings of this image. Reprinted from my article in the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society.

12/01/2021 – Ephemeris – Let’s search for the naked-eye planets and a comet for this week

December 1, 2021 Comments off

This is Bob Moler with Ephemeris for Wednesday, December 1st. Today the Sun will be up for 9 hours and 3 minutes, setting at 5:03, and it will rise tomorrow at 8:01. The Moon, 3 days before new, will rise at 5:45 tomorrow morning.

Let’s search for the naked-eye planets for this week. Venus will be visible in the southwestern evening twilight by 5:30 tonight. It’s a crescent in telescopes. It is moving closer to us, and now appears a bit larger than Jupiter in telescopes. Venus will set at 7:47 pm. By 5:45 pm, both Jupiter and Saturn should be able to be spotted in the southern sky. Saturn will be dimmer, and to its right. It will set first at 9:30 pm, with Jupiter following at 10:56 pm. A new comet named Leonard can be spotted with binoculars about 14 degrees above the bright star Arcturus in the east before 6:30 or 7am tomorrow morning. The spread of your fingers at arm’s length is about 15 degrees. The comet will move lower each morning.

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. That also applies to the times in the addendum below.

Addendum

Evening planets

The evening planets Venus, Saturn and Jupiter at 5:45 pm this evening, December 1, 2021. Created using Stellarium.

Comet Leonard Finder chart

Comet Leonard, designation C/2021 A1, Finder chart looking East at 6:30 am. Arcturus is the brightest star in that direction. The handle of the Big Dipper is above and right of it. The comet is expected to be 7th magnitude, requiring binoculars or a telescope. It is expected to brighten to possibly be visible to the naked eye by the end of next week. No promises though. Created using Stellarium.

The Moon and Mars 12/02/21 7 am

A closeup of the Moon and Mars at 7 am tomorrow morning, December 2, 2021. The star next to the Moon is Zubenelgenubi (south claw of the scorpion), in Libra. The Arabs, who named this star and most others, saw this star as part of Scorpius, to the left and yet to rise.

Telescopic views of the naked-eye planets

Telescopic views of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening at 7 pm, December 1, 2021. Apparent diameters: Venus, 39.41″, 27.9% illuminated; Saturn 15.99″, its rings 37.24″; Jupiter, 38.25″. The ” symbol means seconds of arc (1/3600th of a degree.) Jupiter’s other bright moons are behind the planet at 7 pm. Callisto will reappear on the eastern edge of Jupiter (Io’s side) at 9:13 pm. Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on December 1, 2021. The night ends on the left with sunrise on the 2nd. Click on the image to enlarge it. Created using my LookingUp program.

11/30/2021 – Ephemeris – Previewing December skies

November 30, 2021 Comments off

This is Ephemeris for Tuesday, November 30th. Today the Sun will be up for 9 hours and 4 minutes, setting at 5:03, and it will rise tomorrow at 8:00. The Moon, 3 days past last quarter, will rise at 4:24 tomorrow morning.

Let’s look ahead at the skies of December. We are now in the holiday season and about to celebrate the southernmost travel of the Sun in the sky and its return northward. The Sun will stop its travel south, the winter solstice on the 21st at 10:59 a.m. That will make that day the shortest day in terms of daylight hours. However, the earliest sunset and latest sunrise don’t coincide with that date. The reason is the Earth is closer to the Sun than average and is moving faster in its orbit than it normally does. It skews the sunrise and sunset times, making them later than they would be on average. We have a comet, C/2021 A1 (Leonard), that will be bright enough to be visible in binoculars coming into view in the morning later this week and into the next.

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

December Evening Star Chart

December Evening Star Chart

Star Chart for December 2021 (9 p.m. EST December 15, 2021). Click on image to enlarge. Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 9 pm EST in the evening and 6 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian, West 75° longitude. (An hour 45 minutes behind our daylight saving time meridian during EDT).

December Morning Star Chart

Star Chart for December mornings, 2021 (6 a.m. EST December 15, 2021). Click on image to enlarge. 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.
  • The leaky bowl of the Big Dipper drips on Leo.
  • Follow the arc of the handle of the Big Dipper to the star Arcturus, then
  • Follow the spike to Spica.
  • The Summer Triangle is in red.
  • GemR on the star charts is the radiant of the Geminid meteor shower, which peaks on the morning of the 14th.

Twilight Limits, Nautical and Astronomical

      EST        
  Morning Twilight Evening Twilight Dark Night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2021-12-01 6h20m 6h56m 18h15m 18h51m 18h51m 4h24m 0.07
2021-12-02 6h21m 6h57m 18h15m 18h50m 18h50m 5h45m 0.02
2021-12-03 6h22m 6h57m 18h15m 18h50m 18h50m 6h22m 0
2021-12-04 6h23m 6h58m 18h15m 18h50m 18h50m 6h23m 0.01
2021-12-05 6h24m 6h59m 18h15m 18h50m 18h50m 6h24m 0.05
2021-12-06 6h25m 7h00m 18h15m 18h50m 19h27m 6h25m 0.12
2021-12-07 6h26m 7h01m 18h15m 18h50m 20h43m 6h26m 0.21
2021-12-08 6h27m 7h02m 18h15m 18h50m 22h00m 6h27m 0.31
2021-12-09 6h28m 7h03m 18h15m 18h50m 23h14m 6h28m 0.41
2021-12-10 6h28m 7h04m 18h15m 18h50m 6h28m 0.52
2021-12-11 6h29m 7h05m 18h15m 18h50m 0h25m 6h29m 0.62
2021-12-12 6h30m 7h05m 18h15m 18h51m 1h32m 6h30m 0.71
2021-12-13 6h31m 7h06m 18h15m 18h51m 2h38m 6h31m 0.79
2021-12-14 6h31m 7h07m 18h16m 18h51m 3h42m 6h31m 0.87
2021-12-15 6h32m 7h07m 18h16m 18h51m 4h46m 6h32m 0.92
2021-12-16 6h33m 7h08m 18h16m 18h52m 5h50m 6h33m 0.97
2021-12-17 6h29m 7h05m 18h13m 18h48m 0.99
2021-12-18 6h30m 7h05m 18h13m 18h48m 1
2021-12-19 6h30m 7h06m 18h13m 18h49m 0.99
2021-12-20 6h31m 7h07m 18h14m 18h49m 0.96
2021-12-21 6h31m 7h07m 18h14m 18h50m 18h50m 19h11m 0.92
2021-12-22 6h32m 7h07m 18h15m 18h50m 18h50m 20h16m 0.86
2021-12-23 6h32m 7h08m 18h15m 18h51m 18h51m 21h23m 0.78
2021-12-24 6h33m 7h08m 18h16m 18h51m 18h51m 22h31m 0.7
2021-12-25 6h33m 7h09m 18h17m 18h52m 18h52m 23h40m 0.6
2021-12-26 6h34m 7h09m 18h17m 18h53m 18h53m 0.49
2021-12-27 6h34m 7h09m 18h18m 18h53m 18h53m 0h50m 0.38
2021-12-28 6h34m 7h10m 18h19m 18h54m 18h54m 2h02m 0.27
2021-12-29 6h34m 7h10m 18h19m 18h55m 18h55m 3h18m 0.18
2021-12-30 6h35m 7h10m 18h20m 18h55m 18h55m 4h38m 0.1
2021-12-31 6h35m 7h10m 18h21m 18h56m 18h56m 6h00m 0.04

Twilight calendar was generated using Cartes du Ciel (Sky Charts).

See my blog post: Twilight Zone for the definitions of the different periods of twilight here: https://bobmoler.wordpress.com/2018/09/27/.

NASA Calendar of Planetary Events

     Date     Time    Event
Dec  1  We            Venus: 41.4° E
     3  Fr   9:58 am  Moon Descending Node
     4  Sa   2:34 am  Total Solar Eclipse (Antarctica, Southern Ocean)
     4  Sa   2:43 am  New Moon
     4  Sa   5:01 am  Moon Perigee: 356800 km
     5  Su   9:25 pm  Moon South Dec.: 26.3° S
     6  Mo   7:48 pm  Moon-Venus: 1.9° N
     7  Tu   8:52 pm  Moon-Saturn: 4.2° N
     9  Th   1:07 am  Moon-Jupiter: 4.6° N
    10  Fr   8:36 pm  First Quarter
    14  Tu   1:44 am  Geminid Shower: ZHR = 120
    16  Th   7:12 pm  Moon Ascending Node
    17  Fr   9:16 pm  Moon Apogee: 406300 km
    18  Sa  11:36 pm  Full Moon
    19  Su  11:32 pm  Moon North Dec.: 26.3° N
    21  Tu   4:20 am  Moon-Pollux: 2.9° N
    21  Tu  10:59 am  Winter Solstice
    22  We   5:28 am  Moon-Beehive: 3.6° S
    22  We  10:00 am  Ursid Shower: ZHR = 10
    26  Su   9:24 pm  Last Quarter
    27  Mo   4:17 am  Mars-Antares: 4.5° N
    28  Tu  11:49 pm  Mercury-Venus: 4.2° N
    30  Th   8:07 pm  Moon Descending Node
    31  Fr   3:13 pm  Moon-Mars: 0.9° N

All event times are given for UTC-5 Eastern Standard Time.

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html.

If you go to the above site, you can print out a list like the above for the entire year or calendar pages for your time zone.

Sun and Moon Rising and Setting Events

LU                  Ephemeris of Sky Events for Interlochen/TC
December, 2021    Local time zone: EST
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Wed  1| 08:00a  05:03p  09:03 | 06:12p  06:50a |      Rise 05:45a    8%|
|Thu  2| 08:01a  05:03p  09:01 | 06:12p  06:51a |      Rise 07:09a    3%|
|Fri  3| 08:02a  05:02p  09:00 | 06:12p  06:52a |      Rise 08:33a    0%|
|Sat  4| 08:03a  05:02p  08:59 | 06:12p  06:53a |New   Set  05:18p    1%|
+------+-----------------------+----------------+-----------------------+
|Sun  5| 08:04a  05:02p  08:57 | 06:12p  06:54a |      Set  06:17p    4%|
|Mon  6| 08:05a  05:02p  08:56 | 06:12p  06:55a |      Set  07:27p   11%|
|Tue  7| 08:06a  05:02p  08:55 | 06:12p  06:56a |      Set  08:43p   19%|
|Wed  8| 08:07a  05:02p  08:54 | 06:12p  06:57a |      Set  10:00p   28%|
|Thu  9| 08:08a  05:02p  08:53 | 06:12p  06:58a |      Set  11:14p   39%|
|Fri 10| 08:09a  05:02p  08:52 | 06:12p  06:59a |F Qtr Set  12:25a   49%|
|Sat 11| 08:10a  05:02p  08:51 | 06:12p  06:59a |      Set  01:32a   60%|
+------+-----------------------+----------------+-----------------------+
|Sun 12| 08:11a  05:02p  08:51 | 06:12p  07:00a |      Set  02:37a   69%|
|Mon 13| 08:11a  05:02p  08:50 | 06:12p  07:01a |      Set  03:41a   78%|
|Tue 14| 08:12a  05:02p  08:49 | 06:13p  07:02a |      Set  04:45a   85%|
|Wed 15| 08:13a  05:02p  08:49 | 06:13p  07:02a |      Set  05:50a   91%|
|Thu 16| 08:14a  05:03p  08:49 | 06:13p  07:03a |      Set  06:53a   96%|
|Fri 17| 08:14a  05:03p  08:48 | 06:14p  07:04a |      Set  07:56a   99%|
|Sat 18| 08:15a  05:03p  08:48 | 06:14p  07:04a |Full  Rise 04:34p  100%|
+------+-----------------------+----------------+-----------------------+
|Sun 19| 08:16a  05:04p  08:48 | 06:14p  07:05a |      Rise 05:19p   99%|
|Mon 20| 08:16a  05:04p  08:48 | 06:15p  07:05a |      Rise 06:12p   97%|
|Tue 21| 08:17a  05:05p  08:48 | 06:15p  07:06a |      Rise 07:11p   93%|
|Wed 22| 08:17a  05:05p  08:48 | 06:16p  07:06a |      Rise 08:16p   87%|
|Thu 23| 08:18a  05:06p  08:48 | 06:16p  07:07a |      Rise 09:23p   80%|
|Fri 24| 08:18a  05:06p  08:48 | 06:17p  07:07a |      Rise 10:31p   71%|
|Sat 25| 08:18a  05:07p  08:48 | 06:18p  07:08a |      Rise 11:40p   62%|
+------+-----------------------+----------------+-----------------------+
|Sun 26| 08:19a  05:08p  08:49 | 06:18p  07:08a |L Qtr Rise 12:50a   51%|
|Mon 27| 08:19a  05:08p  08:49 | 06:19p  07:08a |      Rise 02:02a   40%|
|Tue 28| 08:19a  05:09p  08:50 | 06:20p  07:09a |      Rise 03:18a   30%|
|Wed 29| 08:19a  05:10p  08:50 | 06:20p  07:09a |      Rise 04:37a   20%|
|Thu 30| 08:19a  05:11p  08:51 | 06:21p  07:09a |      Rise 06:00a   11%|
|Fri 31| 08:20a  05:12p  08:52 | 06:22p  07:09a |      Rise 07:20a    5%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

Comet Leonard

Comet 2021 A1 Leonard in the morning Dec 2021

Comet Leonard’s positions at 6:30 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for November 27th. The star field will be shifting to the upper right each morning at 6:30 from the November 27th date. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. Plus, the comet tails will not appear as long. The tail may not actually be visible visually. Created using Cartes du Ciel (Sky Charts). Reprinted from my article in the December 2021 issue of the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society.

This is our best shot at spotting the comet. After it passes the Sun and enters the evening sky, the comet will hug the southwest to southern horizon in twilight. I’ll have more on Comet Leonard in the rest of the programs this week.