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

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

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.

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 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).
11/30/2021 – Ephemeris – Previewing December skies
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

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 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.
03/15/2021 – Ephemeris – Newly discovered comet may reach naked-eye brightness by December
This is Ephemeris for Ides of March, Monday, March 15th. Today the Sun will be up for 11 hours and 54 minutes, setting at 7:49, and it will rise tomorrow at 7:52. The Moon, 2 days past new, will set at 10:12 this evening.
Now that daylight saving time is here all the times I give for sunrises and sunsets bump up at least an hour along with anything else the rises or sets. It’s lighter out in the evening now. The end of nautical twilight, by which time it’s dark enough to see most of the stars and constellations ends around 8:21 tonight, but that will continue to advance toward 11 pm by July. On to possibly happier news, a comet was discovered, and is called Comet 2021 A1 (Leonard). It could reach naked eye visibility and be brightest in mid-December. I mean could. Comets are unpredictable, and so is our weather that time of year. I’ll have more on Comet Leonard, its antics and more about comets in general as it heads in from the outer solar system during this year.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Comet C/2021 A1 (Leonard) orbit and position as of March 15, 2021. The vertical lines (I call them stilts) show the orbit’s position above or below the plane of the Earth’s orbit. It will reach its closest point to the Sun on January 3, 2022, just inside Venus’ orbit. Click on the image to enlarge. Credit NASA/JPL Small-Body Database Browser.
03/08/2021 – Ephemeris – 45 years ago today I saw and photographed Comet West!
This is Bob Moler with Ephemeris for International Women’s Day, Monday, March 8th. Today the Sun will be up for 11 hours and 32 minutes, setting at 6:40, and it will rise tomorrow at 7:05. The Moon, 3 days past last quarter, will rise at 5:34 tomorrow morning.
On this day 45 years ago, in 1976, during the first year of these Ephemeris programs I was able to report on, observe and photograph the brightest comet I had seen up till that time: Comet West. It was not supposed to be a bright comet, but as it rounded the Sun, it began to brighten spectacularly. Later I found out that it’s nucleus broke into several fragments, liberating a great quantity of gas and dust. It turned out to be a very dusty comet which ended up in a broad and bright tail. It was going to be visible before sunrise, and this was the first morning in a while it was clear. Even before the head of the comet rose, the tail could be seen rising in the east. I was able to get several photographs of this wonderful comet!
The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Comet West, C/1975 V1, as photographed by me at about 6 am, March 8, 1976. The wide, curved dust tail is most prominent with the narrow blue ion tail pointed more directly at the rising Sun. The small summer constellation of Delphinus the dolphin is to the upper right. The diamond shape of stars at the front of the dolphin’s body is an asterism called Job’s Coffin.
In the image above is tilted about 45 degrees to the horizon in the lower left due to the fact that it was on an equatorial mount, where up and down is north and south in the sky, horizontally is east and west. It’s cocked 45 degrees to the horizon because we are at 45 degrees latitude. Actually the angle is 90 – your latitude which around here is 90 – 45 = 45.
I got up early in the morning of March 8th 1976. I had my telescope mount outside because it takes awhile to set it up to true north and everything. The telescope and camera that mounts on it were taken inside. I just left it there covered with a tarp and wasn’t observing too much that winter. When I got up in wee hours of the morning of the eighth I found out that my telescope mount was buried in the middle of a snowdrift, so I had to dig it out. As I was digging it out I looked to the east and saw the tail of the comet rising before the head did. I then redoubled my efforts and got everything set up so I could take photographs of the comet.
I had built a small telescope a few years before for a solar eclipse as a kind of contingency camera in case my automatic cameras I had built didn’t work. It was a 108 mm f/6 reflecting telescope that I attached a camera back to and took some minute or two long exposures that way. I then realized that the sky was getting brighter, so I quickly switched, and took a couple of wide angle pictures with the 50 mm lens with tracking. That’s one of them above that shows the lovely comet with the long tail.
12/29/2020 – Ephemeris – 2020 the bad and the good in astronomy
This is Ephemeris for Tuesday, December 29th. Today the Sun will be up for 8 hours and 50 minutes, setting at 5:10, and it will rise tomorrow at 8:19. The Moon, at full today, will rise at 4:45 this evening.
2020 has been a terrible year due mostly to the COVID-19 pandemic that cost over 300 thousand American lives. It also saw the end of the 1,000 foot (305 meter) radio telescope dish set into a natural bowl near the north shore of Puerto Rico, 8.5 miles south of the city of Arecibo. The Arecibo Radio Telescope was until earlier this year the world’s largest single telescope. It also possessed a powerful radar transmitter allowing radar imaging of planets, moons and asteroids. It started to collapse several months ago and finally gave way December 1st.
On a positive note we were graced by the bright Comet NEOWISE visible first in the morning, then in the evening last July. It was the brightest comet in the northern skies since Comet Hale-Bopp appeared in 1997.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Aerial view of the Arecibo telescope after the collapse of the 900 ton feed platform suspended above the dish on December 1, 2020. Credit: Ricardo Arduengo/AFP via Getty Images
07/29/2020 – Ephemeris – Let’s look at a the naked-eye planets and not so naked-eye comets for this week
This is Bob Moler with Ephemeris for Wednesday, July 29th. Today the Sun will be up for 14 hours and 45 minutes, setting at 9:11, and it will rise tomorrow at 6:27. The Moon, 2 days past first quarter, will set at 2:27 tomorrow morning.
Let’s look at a the naked-eye planets for this week. Jupiter and Saturn are both low in the southeastern sky in the evening. Jupiter is the very bright one. To the left of it will be Saturn. Both planets will be up most of the night with Jupiter setting first at 5:05 am tomorrow morning and Saturn following at 5:44 am. Comet NEOWISE is in the evening sky fading to below naked-eye visibility and also it is hampered by the bright moon. It was a great sight in this bleak year of 2020. The next planet visible will be Mars which will rise at 12:03 am. Its now down to 60.6 million miles (97.5 million km) away, as the Earth slowly overtakes it at the rate of about 3.6 million miles (5.7 million km) a week. Venus will rise at 3:14 am in the east-northeast as our Morning Star. Finally Mercury will rise at 4:59 am.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum

Evening planets Jupiter and Saturn seen in the southeast at 10 pm, about 45 minutes after sunset July 29, 2020. Click on the image to enlarge. Created using Stellarium.

The morning planets as seen at 5:30 am or about an hour before sunrise July 30,2020. Mercury is showing up, rising at 4:56 amClick on the image to enlarge. Created using Stellarium.

The planets as seen in a telescope (north up) with the same magnification tonight and tomorrow July 29/30, 2020. Apparent diameters: Jupiter, 47.26″; Saturn, 18.45″, rings, 42.98″ at 10 pm. Mars, 14.40″, and Venus 27.78″ at 5:30 am. Mars also displays an enlargement showing surface detail. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge. Created using Cartes du Ciel (Sky Charts).