Archive
02/12/2021 – Ephemeris – Monoceros the unicorn
This is Ephemeris for Darwin Day, Friday, February 12th. Today the Sun will be up for 10 hours and 20 minutes, setting at 6:07, and it will rise tomorrow at 7:45. The Moon, 1 day past new, will set at 7:07 this evening.
Among all the constellations in the sky of animals real and mythical, there is also a unicorn. It’s called Monoceros, and inhabits the southeastern sky at 8 p.m. mostly bounded by Orion on the right, Canis Major, the great dog below and Canis Minor, the little dog to the left and above. Unfortunately for observers without a telescope Monoceros, is devoid of any but the faintest stars. Maybe that’s why no one sees unicorns anymore. It has many faint stars because the Milky Way runs through it. To the telescope it is a feast of faint nebulae or clouds of gas and dust, the birthplace of stars, including the red rose of the Rosette Nebula, and Hagrid’s Dragon Cluster (NGC 2301). It also contains a beautiful telescopic triple star system, Beta (β) Monocerotis.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Monoceros finder chart showing neighboring constellations for about 8 pm in mid-February. Created using Stellarium.
The brighter stars of NGC 2301 (Hagrid’s Dragon Cluster, AKA Great Bird Cluster and Copeland’s Golden Worm). It’s also in two other catalogs: Cr 119 and Mel 54. Created using Stellarium and GIMP. Dragon from “Dragon Flying Cycle” on YouTube by Simon Hussey.
Deep Sky Objects in and around Monoceros. Click on the image to enlarge. Created using Stellarium.
Rosette Nebula in the infrared from the Spitzer Space Telescope. The star cluster in the center is visible in a telescope, but the nebula is strictly photographic. Credit: NASA/JPL/Caltech.
Telescopic Beta Monocerotis. William Hershel, discoverer of Uranus, said that it was “One of the most beautiful sights in the heavens.” Credit: F. Ringwald, Fresno State.
02/11/2021 – Ephemeris – The Winter Triangle
This is Ephemeris for Thursday, February 11th. Today the Sun will be up for 10 hours and 17 minutes, setting at 6:06, and it will rise tomorrow at 7:47. The Moon is new today, and won’t be visible.
I usually talk about the Winter Circle of bright stars, but some other astronomers talk about the Winter Triangle. The stars involved are Betelgeuse in the hunter Orion, Sirius in Canis Major, Orion’s large hunting dog, and Procyon in Canis Minor, his other small hunting dog. These three stars enclose a rather blank piece of sky with the faint Milky Way running through it and the almost invisible constellation of Monoceros the unicorn. The Summer Triangle has three bright stars with no other close competition. The Winter Triangle has four other bright stars near it. Any three of these would make a nice triangle. One of these constellations Canis Minor is tiny, with Procyon and one other star. It makes me think of a dachshund, or maybe, if I’m hungry, a hot dog.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Winter Triangle finder animation. It shows the star field, named first magnitude stars, then their constellations, then the Winter Triangle and constellations of the three stars. Click on the image to enlarge. Created using Stellarium and GIMP.
02/10/2021 – Ephemeris – Let’s have a lookout for the naked-eye planets for this week
This is Ephemeris for Wednesday, February 10th. Today the Sun will be up for 10 hours and 14 minutes, setting at 6:04, and it will rise tomorrow at 7:48. The Moon, 1 day before new, will rise at 8:11 tomorrow morning.
Let’s have a lookout for the naked-eye planets for this week. It’s slim pickings for the bright naked-eye planets, known from antiquity, in our skies now. Only Mars can be spotted. The rest of them are hanging out in the direction of the Sun and won’t be seen until spring in the morning sky. Mars can be found high in the southwest at 8 pm. Mars is increasing its speed eastward through the constellation of Aries the ram, which it’s two thirds the way through, and will set at 1:38 am. Of the outer planets Mars is the fastest, being the nearest to the Sun, so unlike Jupiter, Saturn and the stars which rise and set about four minutes earlier each night, Mars sets about a minute earlier each night now.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars with zodiacal constellations along its future path with Orion as a prominent marker. The orange line is the ecliptic, the path of the Sun in the sky, and near which the planets can be found. Along with the constellation lines in blue are the official astronomical constellation boundaries in red. Click on the image to enlarge. Created using Stellarium.
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on February 10, 2021. The night ends on the left with sunrise on the 11th. There is a planet traffic jam in the morning and the labels for Jupiter and Venus overlap. Unfortunately these planets rise too soon before the Sun to be seen for us up north. Click on the image to enlarge. Created using my LookingUp program.
02/09/2021 – Ephemeris – Happy Mars New Year
This is Ephemeris for Tuesday, February 9th. Today the Sun will be up for 10 hours and 11 minutes, setting at 6:03, and it will rise tomorrow at 7:49. The Moon, 2 days before new, will rise at 7:35 tomorrow morning.
Thanks to Dr. Phil Plait’s Bad Astronomy Blog I found out that last Sunday was Mars’ New Year’s Day for year 36*. I didn’t know they were counting them. Year 1 started on the first day of spring for Mars’ Northern Hemisphere, April 11th 1955. Like for most calendars the year numbering wasn’t created until later, from a scientific paper published in 2000 which followed the seasonal changes on Mars and had to put them in Mars years to make sense, rather than Earth years. I approve. As a teenager with my first telescope I eagerly awaited Mars’ especially close approach in 1956. By the Mars calendar that was in martian year 1. Back then our ignorance of Mars was profound. But a decade later the Mariner 4 spacecraft flew past Mars taking the first closeup pictures.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
* For some reason I said it was year 38 in the broadcast.
Addendum
Earth and Mars orbits and seasons compared as seen from the north. Planet motion is counterclockwise. Vernal equinox is the position of the planet for the Northern Hemisphere spring Source: Wikipedia user Areong.
Additional links:
https://www.syfy.com/syfywire/happy-martian-new-year
https://en.wikipedia.org/wiki/Timekeeping_on_Mars
https://www.planetary.org/articles/mars-calendar
02/08/2021 – Ephemeris – A look at Gemini the twins
This is Ephemeris for Monday, February 8th. Today the Sun will be up for 10 hours and 9 minutes, setting at 6:01, and it will rise tomorrow at 7:51. The Moon, 3 days before new, will rise at 6:49 tomorrow morning.
Let’s look at another of the winter constellations, and a member of the Zodiac. The constellation of Gemini the Twins is visible high in the southeast, above and left of Orion the hunter at 9 p.m. The namesake stars of the two lads, will be at the left end of Gemini, are nearly overhead and vertically aligned. Castor is on top, while the slightly brighter Pollux is below. From them come two lines of stars that outline the two extending toward Orion. In Greek mythology the lads were half brothers, Castor was fathered by a mere mortal, while Pollux was fathered by Zeus, but were born together as twins. When Castor was killed during the quest for the Golden Fleece, Pollux pleaded with Zeus to let him die also, so Zeus placed them together in the sky, so they could be together forever.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Gemini finder animation for early February at 9 pm (about 3 hours after sunset). Created using Stellarium and GIMP.
02/04/2021 – Ephemeris – Finding Orion’s larger hunting dog
This is Bob Moler with Ephemeris for Thursday, February 4th. Today the Sun will be up for 9 hours and 58 minutes, setting at 5:56, and it will rise tomorrow at 7:56. The Moon, at last quarter today, will rise at 2:19 tomorrow morning.
The great winter constellation or star group Orion the hunter, is located in the southern sky at 9 p.m. His elongated rectangle of a torso is vertical. In the center of the rectangle are three stars in a line that make his belt. As a hunter, especially one of old, he has two hunting dogs. The larger, Canis Major can be found by following the three belt stars of Orion down and to the left. They point to Sirius, the brightest night-time star, also known as the Dog Star. It’s in the heart of a stick figure dog low in the southeast facing Orion that appears to be begging. There’s a fine star cluster, called Messier, or M 41, at the 5 o’clock position from Sirius. It’s easily visible in binoculars or a small telescope.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion and his hunting dogs with pointers as seen February. I didn’t have time in the program to mention Canis Minor, the little dog. I expect to cover it in the future, or you can search for Canis Minor in the search box above. Created using Stellarium.
I did not have time to talk about Canis Minor in this program due to the inclusion of M 41. I plan to cover Canis Minor soon. I have in the past. Search for Canis Minor in the search box above.
Star cluster M 41 finder chart. Created using Stellarium.
M 41 up close. Image courtesy of Tim Hunter and James McGaha, Grasslands Observatory at http://www.3towers.com
02/03/2021 – Ephemeris – Let’s have a lookout for the naked-eye planets
This is Ephemeris for Wednesday, February 3rd. Today the Sun will be up for 9 hours and 55 minutes, setting at 5:54, and it will rise tomorrow at 7:57. The Moon, 1 day before last quarter, will rise at 1:03 tomorrow morning.
Let’s have a lookout for the naked-eye planets for this week. It’s slim pickings for the bright naked-eye planets, known from antiquity in our skies right now. Only Mars can be spotted. The rest of them are hanging out in the direction of the Sun and won’t be seen for a month or more. Mars can be found high in the south at 7 pm. It will actually be due south at 6:30 tonight. Mars is increasing its speed eastward through the constellation of Aries the ram, which it’s halfway through, and will set at 1:45 am. Of the outer planets Mars is the fastest, being the closest to the Sun, so unlike Jupiter, Saturn and the stars which rise and set about four minutes earlier each night, Mars rises and sets about a minute and a half earlier each day.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars finder chart. Showing Mars in Aries. Also shown are Taurus and Orion. All are seen tonight at 8 pm, February 3, 2021. Click on the image to enlarge. Created using Stellarium.
The Moon as it might look like at last quarter tomorrow morning at 6 am, February 4, 2021. Created using Stellarium.
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on February 3, 2021. The night ends on the left with sunrise on the 4th. I’m afraid that the labels for Jupiter and the Sun overlap, since the planets and Sun are very close. Click on the image to enlarge. Created using my LookingUp program.
02/02/2021 – Ephemeris – Happy Groundhog Day
This is Bob Moler with Ephemeris for Ground Hog Day, Tuesday, February 2nd. Today the Sun will be up for 9 hours and 53 minutes, setting at 5:53, and it will rise tomorrow at 7:59. The Moon, 2 days before last quarter, will rise at 11:48 this evening.
I’m not sure if Punxsutawney Phil will see his shadow this morning or not, but February 2nd was a special day to the ancients. It is also Candlemas day for the Catholic Church. It is also celebrated as a cross-quarter day. The middle of the season of Winter, though the exact date of the middle of winter is the 4th. And if Phil sees his shadow, and we do get 6 more weeks of winter, that’s OK too. By the calendar it is actually 6 weeks and 5 days to the vernal or spring equinox, the official end of winter. But this is northern Michigan. Of the other cross-quarter days, only one stands out today. It’s May 1st, May Day. The way this year has been going, winter has had a hard time getting started. But when it gets going… Look out!
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Poor Punxsutawney Phil, rousted out of his mid winter nap on a previous Groundhog Day. Phil looks kind of grumpy. I don’t blame him. Credit: http://www.fuzzytoday.com.
02/01/2021 – Ephemeris – Previewing February Skies
This is Ephemeris for Monday, February 1st. Today the Sun will be up for 9 hours and 50 minutes, setting at 5:51, and it will rise tomorrow at 8:00. The Moon, 3 days before last quarter, will rise at 10:33 this evening. | February is the shortest month, even so the daylight hours throughout the month will be getting longer. Daylight hours will increase from 9 hours and 50 minutes today to 11 hours and 7 minutes on the 28th. The sunrise time will decrease from 8:01 today to 7:21 at months end. The sunset times will increase from 5:51 today to 6:29 on the 28th. Along with that the altitude of the Sun at noon will increase from 28.4 degrees today to 37.6 degrees at month’s end. It will be a degree lower for folks in the Straits area because they are a degree of latitude farther north. Local noon, by the way for Interlochen and Traverse City is about 12:56 p.m.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Star Chart for February 2021 (9 p.m. EST February 15, 2021). Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 9 p.m. 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. (An hour 45 minutes behind our daylight saving time meridian during EDT). To duplicate the star positions on a planisphere (rotating star finder) you may have to set it to 1 hour 45 minutes earlier than the current time.
Note the chart times of 9 p.m. and 6 a.m. are for the 15th. For each week before the 15th add ½ hour (28 minutes if you’re picky). For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog.
February Morning Star Chart
Star Chart for February mornings 2021 (6 a.m. EST February 15, 2021). Created using my LookingUp program. Click on image to enlarge.
For a list of constellation names to go with the abbreviations click here.
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
- Follow the arc of the handle of the Big Dipper to the star Arcturus, and
- Extend like a spike to Spica,
- The Summer Triangle is in red.
Twilight Limits, Nautical and Astronomical
| EST | |||||||
| Morning twilight | Evening twilight | Dark night | Moon | ||||
| Date | Astro. | Nautical | Nautical | Astro. | Start | End | Illum. |
| 2021-02-01 | 6h22m | 6h56m | 18h56m | 19h30m | 19h30m | 22h33m | 0.78 |
| 2021-02-02 | 6h21m | 6h55m | 18h57m | 19h31m | 19h31m | 23h48m | 0.67 |
| 2021-02-03 | 6h20m | 6h54m | 18h59m | 19h33m | 19h33m | – | 0.56 |
| 2021-02-04 | 6h19m | 6h53m | 19h00m | 19h34m | 19h34m | 1h03m | 0.45 |
| 2021-02-05 | 6h18m | 6h52m | 19h01m | 19h35m | 19h35m | 2h20m | 0.34 |
| 2021-02-06 | 6h16m | 6h50m | 19h02m | 19h36m | 19h36m | 3h35m | 0.23 |
| 2021-02-07 | 6h15m | 6h49m | 19h04m | 19h38m | 19h38m | 4h48m | 0.15 |
| 2021-02-08 | 6h14m | 6h48m | 19h05m | 19h39m | 19h39m | 5h54m | 0.08 |
| 2021-02-09 | 6h13m | 6h47m | 19h06m | 19h40m | 19h40m | 6h13m | 0.03 |
| 2021-02-10 | 6h12m | 6h46m | 19h08m | 19h41m | 19h41m | 6h12m | 0 |
| 2021-02-11 | 6h10m | 6h44m | 19h09m | 19h43m | 19h43m | 6h10m | 0 |
| 2021-02-12 | 6h09m | 6h43m | 19h10m | 19h44m | 19h44m | 6h09m | 0.02 |
| 2021-02-13 | 6h08m | 6h42m | 19h11m | 19h45m | 20h14m | 6h08m | 0.06 |
| 2021-02-14 | 6h06m | 6h40m | 19h13m | 19h47m | 21h19m | 6h06m | 0.12 |
| 2021-02-15 | 6h05m | 6h39m | 19h14m | 19h48m | 22h22m | 6h05m | 0.19 |
| 2021-02-16 | 6h04m | 6h37m | 19h15m | 19h49m | 23h25m | 6h04m | 0.27 |
| 2021-02-17 | 6h02m | 6h36m | 19h17m | 19h50m | – | 6h02m | 0.35 |
| 2021-02-18 | 6h01m | 6h34m | 19h18m | 19h52m | 0h27m | 6h01m | 0.45 |
| 2021-02-19 | 5h59m | 6h33m | 19h19m | 19h53m | 1h30m | 5h59m | 0.54 |
| 2021-02-20 | 5h58m | 6h32m | 19h21m | 19h54m | 2h33m | 5h58m | 0.64 |
| 2021-02-21 | 5h56m | 6h30m | 19h22m | 19h56m | 3h35m | 5h56m | 0.73 |
| 2021-02-22 | 5h55m | 6h28m | 19h23m | 19h57m | 4h34m | 5h55m | 0.81 |
| 2021-02-23 | 5h53m | 6h27m | 19h24m | 19h58m | 5h28m | 5h53m | 0.89 |
| 2021-02-24 | 5h52m | 6h25m | 19h26m | 19h59m | – | – | 0.94 |
| 2021-02-25 | 5h50m | 6h24m | 19h27m | 20h01m | – | – | 0.98 |
| 2021-02-26 | 5h48m | 6h22m | 19h28m | 20h02m | – | – | 1 |
| 2021-02-27 | 5h47m | 6h20m | 19h30m | 20h03m | – | – | 0.99 |
| 2021-02-28 | 5h45m | 6h19m | 19h31m | 20h05m | 20h05m | 20h16m | 0.95 |
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/2019/09/27/
NASA Calendar of Planetary Events
Date Time Event
Feb 1 Mo Venus: 13° W
3 We 2:33 pm Moon Perigee: 370,100 km
4 Th 12:37 pm Last Quarter
6 Sa 7:29 pm Moon Descending Node
8 Mo 8:39 am Mercury Inferior Conjunction
8 Mo 10:34 am Moon South Dec.: 25° S
11 Th 2:06 pm New Moon
18 Th 5:22 am Moon Apogee: 404,500 km
18 Th 5:47 pm Moon-Mars: 4.1° N
19 Fr 1:47 pm First Quarter
20 Sa 8:44 pm Moon Ascending Node
22 Mo 7:12 pm Moon North Dec.: 25.1° N
23 Tu 2:38 am Mercury-Saturn: 4° N
24 We 7:16 pm Moon-Beehive: 2.5° S
27 Sa 3:17 am Full Moon
All event times are given for UTC-5:00: Eastern Standard or Daylight 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 February, 2021 Local time zone: EST +-----------------------------------------------------------------------+ | DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM | | | RISE SET HOURS | END START |PHASE SET** TIME FRACTN| +=======================================================================+ |Mon 1| 08:01a 05:51p 09:50 | 06:57p 06:55a | Rise 10:33p 79%| |Tue 2| 08:00a 05:53p 09:53 | 06:59p 06:54a | Rise 11:48p 69%| |Wed 3| 07:59a 05:54p 09:55 | 07:00p 06:53a | Rise 01:03a 58%| |Thu 4| 07:57a 05:56p 09:58 | 07:01p 06:52a |L Qtr Rise 02:19a 47%| |Fri 5| 07:56a 05:57p 10:00 | 07:03p 06:51a | Rise 03:35a 36%| |Sat 6| 07:55a 05:59p 10:03 | 07:04p 06:50a | Rise 04:48a 25%| +------+-----------------------+----------------+-----------------------+ |Sun 7| 07:54a 06:00p 10:06 | 07:05p 06:48a | Rise 05:53a 16%| |Mon 8| 07:52a 06:01p 10:09 | 07:06p 06:47a | Rise 06:49a 9%| |Tue 9| 07:51a 06:03p 10:11 | 07:08p 06:46a | Rise 07:35a 4%| |Wed 10| 07:49a 06:04p 10:14 | 07:09p 06:45a | Rise 08:11a 1%| |Thu 11| 07:48a 06:06p 10:17 | 07:10p 06:43a |New Set 05:57p 0%| |Fri 12| 07:47a 06:07p 10:20 | 07:12p 06:42a | Set 07:07p 2%| |Sat 13| 07:45a 06:08p 10:23 | 07:13p 06:41a | Set 08:14p 5%| +------+-----------------------+----------------+-----------------------+ |Sun 14| 07:44a 06:10p 10:26 | 07:14p 06:39a | Set 09:19p 11%| |Mon 15| 07:42a 06:11p 10:29 | 07:15p 06:38a | Set 10:22p 17%| |Tue 16| 07:41a 06:13p 10:32 | 07:17p 06:37a | Set 11:24p 25%| |Wed 17| 07:39a 06:14p 10:34 | 07:18p 06:35a | Set 12:27a 34%| |Thu 18| 07:38a 06:15p 10:37 | 07:19p 06:34a | Set 01:30a 43%| |Fri 19| 07:36a 06:17p 10:40 | 07:21p 06:32a |F Qtr Set 02:32a 52%| |Sat 20| 07:34a 06:18p 10:43 | 07:22p 06:31a | Set 03:34a 61%| +------+-----------------------+----------------+-----------------------+ |Sun 21| 07:33a 06:20p 10:46 | 07:23p 06:29a | Set 04:33a 71%| |Mon 22| 07:31a 06:21p 10:49 | 07:25p 06:28a | Set 05:28a 79%| |Tue 23| 07:30a 06:22p 10:52 | 07:26p 06:26a | Set 06:15a 87%| |Wed 24| 07:28a 06:24p 10:55 | 07:27p 06:25a | Set 06:56a 93%| |Thu 25| 07:26a 06:25p 10:58 | 07:28p 06:23a | Set 07:30a 98%| |Fri 26| 07:24a 06:26p 11:01 | 07:30p 06:21a | Set 07:59a 100%| |Sat 27| 07:23a 06:28p 11:05 | 07:31p 06:20a |Full Rise 06:59p 99%| +------+-----------------------+----------------+-----------------------+ |Sun 28| 07:21a 06:29p 11:08 | 07:32p 06:18a | Rise 08:16p 96%| +-----------------------------------------------------------------------+ * Nautical Twilight ** Moonrise or moonset, whichever occurs between sunrise and sunset
Created using my LookingUp for DOS output as HTML.
Bob Moler's Ephemeris Blog 