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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.

03/15/2021 – Ephemeris – Newly discovered comet may reach naked-eye brightness by December

March 15, 2021 Comments off

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 Leonard orbit

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!

March 8, 2021 Comments off

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 at 6 am, March 8, 1976

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.

Comet West 108mm f/6

Comet West taken through the 108 mm f/6 telescope around 5:30 am, March 8, 1976 by a much younger me.

12/29/2020 – Ephemeris – 2020 the bad and the good in astronomy

December 30, 2020 Comments off

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

Arecibo telescope collapse

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

NEOWISE in the morning

My photograph of Comet NEOWISE at 4:40 am over the west arm of Grand Traverse Bay south of the Discovery Pier off M22. (For non-Michigander astronomers M22 is not the globular star cluster in Sagittarius, but a very scenic Michigan state road.) Click on the image to enlarge.

NEOWISE from backyard over tall shrubery

Comet NEOWISE from backyard over tall shrubbery 11:18 pm July 16, 2020. I didn’t have time to focus properly which actually accentuates the stars.

07/29/2020 – Ephemeris – Let’s look at a the naked-eye planets and not so naked-eye comets for this week

July 29, 2020 Comments off

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

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.

Binocular Moon

The gibbous Moon as it might be seen tonight at 10 pm July 29, 2020. Created using Stellarium.

Morning planets

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.

Planets and the Moon on a single night

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).

Planets and the Moon on a single night

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on July 29, 2020. The night ends on the left with sunrise on the 30th. Click on the image to enlarge. Created using my LookingUp program.

Comets NEOWISE and Lemmon at 11 pm for the week

Finder chart for Comets NEOWISE and Lemmon at 11 pm for the week of 07/29/20 to 08/04/20. NEOWISE will be a visible in binoculars. Lemmon will require a telescope. Labels give name, month/day and predicted magnitude. Click on the chart to enlarge. Created using Cartes du Ciel (Sky Charts).