Archive
01/31/2023 – Ephemeris – Previewing February skies
This is Ephemeris for Tuesday, January 31st. Today the Sun will be up for 9 hours and 46 minutes, setting at 5:49, and it will rise tomorrow at 8:02. The Moon, 3 days past first quarter, will set at 5:36 tomorrow morning.
February is the shortest month, even so, the daylight hours throughout the month will be getting longer. Daylight hours will expand from 9 hours and 49 minutes tomorrow the first, to 11 hours and 6 minutes on the 28th. The sunrise time will drop from 8:02 tomorrow to 7:22 at month’s end. The sunset times will extend from 5:51 tomorrow to 6:28 on the 28th. Along with that, the altitude of the Sun at local noon will increase from 28 degrees tomorrow to nearly 38 degrees at month’s end. Local noon, by the way, for Interlochen and Traverse City, when the Sun is due south, will be 12:57 p.m. at mid-month. Venus and Jupiter will appear to approach each other all month, in the western evening sky, coming into conjunction March 1st.
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
February Evening Star Chart

Star Chart for February 2023, (9 p.m. EST February 15, 2023). 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, 2023 (6 a.m. EST February 15, 2023). No naked-eye planets are visible. 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. |
2023-02-01 | 6h22m | 6h57m | 18h56m | 19h30m | 5h37m | 6h22m | 0.89 |
2023-02-02 | 6h21m | 6h56m | 18h57m | 19h31m | – | – | 0.94 |
2023-02-03 | 6h20m | 6h54m | 18h58m | 19h32m | – | – | 0.98 |
2023-02-04 | 6h19m | 6h53m | 19h00m | 19h34m | – | – | 1.00 |
2023-02-05 | 6h18m | 6h52m | 19h01m | 19h35m | – | – | 1.00 |
2023-02-06 | 6h17m | 6h51m | 19h02m | 19h36m | – | – | 0.98 |
2023-02-07 | 6h16m | 6h50m | 19h03m | 19h37m | 19h37m | 19h58m | 0.95 |
2023-02-08 | 6h15m | 6h49m | 19h05m | 19h39m | 19h39m | 21h03m | 0.90 |
2023-02-09 | 6h14m | 6h48m | 19h06m | 19h40m | 19h40m | 22h08m | 0.83 |
2023-02-10 | 6h13m | 6h46m | 19h07m | 19h41m | 19h41m | 23h14m | 0.75 |
2023-02-11 | 6h11m | 6h45m | 19h09m | 19h42m | 19h42m | – | 0.65 |
2023-02-12 | 6h10m | 6h44m | 19h10m | 19h44m | 19h44m | 0h24m | 0.55 |
2023-02-13 | 6h09m | 6h42m | 19h11m | 19h45m | 19h45m | 1h36m | 0.44 |
2023-02-14 | 6h07m | 6h41m | 19h12m | 19h46m | 19h46m | 2h52m | 0.33 |
2023-02-15 | 6h06m | 6h40m | 19h14m | 19h47m | 19h47m | 4h07m | 0.23 |
2023-02-16 | 6h05m | 6h38m | 19h15m | 19h49m | 19h49m | 5h18m | 0.14 |
2023-02-17 | 6h03m | 6h37m | 19h16m | 19h50m | 19h50m | 6h03m | 0.06 |
2023-02-18 | 6h02m | 6h35m | 19h18m | 19h51m | 19h51m | 6h02m | 0.02 |
2023-02-19 | 6h00m | 6h34m | 19h19m | 19h53m | 19h53m | 6h00m | 0.00 |
2023-02-20 | 5h59m | 6h32m | 19h20m | 19h54m | 19h54m | 5h59m | 0.01 |
2023-02-21 | 5h57m | 6h31m | 19h21m | 19h55m | 20h16m | 5h57m | 0.05 |
2023-02-22 | 5h56m | 6h29m | 19h23m | 19h56m | 21h34m | 5h56m | 0.12 |
2023-02-23 | 5h54m | 6h28m | 19h24m | 19h58m | 22h49m | 5h54m | 0.20 |
2023-02-24 | 5h53m | 6h26m | 19h25m | 19h59m | – | 5h53m | 0.29 |
2023-02-25 | 5h51m | 6h25m | 19h27m | 20h00m | 0h03m | 5h51m | 0.39 |
2023-02-26 | 5h49m | 6h23m | 19h28m | 20h02m | 1h15m | 5h49m | 0.49 |
2023-02-27 | 5h48m | 6h21m | 19h29m | 20h03m | 2h25m | 5h48m | 0.59 |
2023-02-28 | 5h46m | 6h20m | 19h31m | 20h04m | 3h29m | 5h46m | 0.68 |
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
Feb 1 We Venus: 24.4° E 2 Th 3:18 am Moon North Dec.: 27.5° N 3 Fr 2:47 pm Moon-Pollux: 2.1° N 4 Sa 3:55 am Moon Apogee: 406,500 km 4 Sa 4:32 pm Moon-Beehive: 3.9° S 5 Su 1:29 pm Full Snow Moon 12 Su 2:31 am Moon Descending Node 13 Mo 11:01 am Last Quarter 14 Tu 1:09 pm Moon-Antares: 1.9° S 16 Th 9:36 am Moon South Dec.: 27.6° S 16 Th 11:17 am Saturn Conjunction 19 Su 4:06 am Moon Perigee: 358,300 km 20 Mo 2:06 am New Moon 22 We 2:57 am Moon-Venus: 2.1° N 22 We 4:58 pm Moon-Jupiter: 1.2° N 24 Fr 1:56 pm Moon Ascending Node 26 Su 9:42 am Moon-Pleiades: 2.2° N 27 Mo 3:06 am First Quarter 27 Mo 11:32 pm Moon-Mars: 1.2° S Mar 1 We Venus: 30.6° E
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, 2023 Local time zone: EST +-----------------------------------------------------------------------+ | DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM | | | RISE SET HOURS | END START |PHASE SET** TIME FRACTN| +=======================================================================+ |Wed 1| 08:02a 05:51p 09:49 | 06:57p 06:55a | Set 06:31a 88%| |Thu 2| 08:00a 05:52p 09:51 | 06:58p 06:54a | Set 07:16a 93%| |Fri 3| 07:59a 05:54p 09:54 | 06:59p 06:53a | Set 07:54a 97%| |Sat 4| 07:58a 05:55p 09:56 | 07:01p 06:52a | Set 08:24a 99%| +------+-----------------------+----------------+-----------------------+ |Sun 5| 07:57a 05:56p 09:59 | 07:02p 06:51a |Full Rise 05:47p 100%| |Mon 6| 07:55a 05:58p 10:02 | 07:03p 06:50a | Rise 06:53p 98%| |Tue 7| 07:54a 05:59p 10:05 | 07:05p 06:49a | Rise 07:58p 95%| |Wed 8| 07:53a 06:01p 10:07 | 07:06p 06:48a | Rise 09:02p 91%| |Thu 9| 07:52a 06:02p 10:10 | 07:07p 06:47a | Rise 10:07p 84%| |Fri 10| 07:50a 06:04p 10:13 | 07:08p 06:45a | Rise 11:14p 76%| |Sat 11| 07:49a 06:05p 10:16 | 07:10p 06:44a | Rise 12:23a 67%| +------+-----------------------+----------------+-----------------------+ |Sun 12| 07:47a 06:06p 10:19 | 07:11p 06:43a | Rise 01:36a 57%| |Mon 13| 07:46a 06:08p 10:21 | 07:12p 06:41a |L Qtr Rise 02:51a 46%| |Tue 14| 07:44a 06:09p 10:24 | 07:14p 06:40a | Rise 04:07a 36%| |Wed 15| 07:43a 06:11p 10:27 | 07:15p 06:39a | Rise 05:18a 25%| |Thu 16| 07:41a 06:12p 10:30 | 07:16p 06:37a | Rise 06:19a 16%| |Fri 17| 07:40a 06:13p 10:33 | 07:17p 06:36a | Rise 07:07a 8%| |Sat 18| 07:38a 06:15p 10:36 | 07:19p 06:34a | Rise 07:44a 3%| +------+-----------------------+----------------+-----------------------+ |Sun 19| 07:37a 06:16p 10:39 | 07:20p 06:33a | Rise 08:13a 0%| |Mon 20| 07:35a 06:18p 10:42 | 07:21p 06:31a |New Set 06:54p 1%| |Tue 21| 07:34a 06:19p 10:45 | 07:23p 06:30a | Set 08:15p 4%| |Wed 22| 07:32a 06:20p 10:48 | 07:24p 06:28a | Set 09:33p 10%| |Thu 23| 07:30a 06:22p 10:51 | 07:25p 06:27a | Set 10:49p 18%| |Fri 24| 07:29a 06:23p 10:54 | 07:27p 06:25a | Set 12:02a 27%| |Sat 25| 07:27a 06:24p 10:57 | 07:28p 06:24a | Set 01:15a 37%| +------+-----------------------+----------------+-----------------------+ |Sun 26| 07:25a 06:26p 11:00 | 07:29p 06:22a | Set 02:24a 47%| |Mon 27| 07:24a 06:27p 11:03 | 07:30p 06:20a |F Qtr Set 03:29a 56%| |Tue 28| 07:22a 06:28p 11:06 | 07:32p 06:19a | Set 04:27a 66%| +-----------------------------------------------------------------------+ * Nautical Twilight ** Moonrise or moonset, whichever occurs between sunrise and sunset
Created using my LookingUp for MS-DOS output as HTML.
01/30/2023 – Ephemeris – Two planetary events are happening today
This is Ephemeris for Monday, January 30th. Today the Sun will be up for 9 hours and 44 minutes, setting at 5:48, and it will rise tomorrow at 8:03. The Moon, 2 days past first quarter, will set at 4:34 tomorrow morning.
Today, the planet Mercury was seen as far away from the Sun as it can get for this time of year in the morning sky. It’s called “greatest western elongation”, and it’s distance from the sun and angle is 25 degrees. It’s going to stay pretty close to that for about the next week or so, it’ll be visible if it ever clears up. This is about the latest time one can see Mercury morning elongations this for this time of year. We’re running out of the correct angles for it. This evening, if it’s clear, the planet of Mars will appear near the waxing gibbous Moon. Early on in the evening Mars will be to the upper left of the Moon, which will be approaching it by about its own diameter every hour, until about 1 o’clock in the morning when Mars will it’s closest above the Moon it should be a striking sight.
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
01/27/2023 – Ephemeris – Where is comet ZTF this weekend?

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?

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.
01/25/2023 – Ephemeris – Let’s see where the naked-eye planets have wandered off to this week
This is Bob Moler with Ephemeris for Wednesday, January 25th. Today the Sun will be up for 9 hours and 32 minutes, setting at 5:41, and it will rise tomorrow at 8:08. The Moon, 3 days before first quarter, will set at 10:42 this evening.
Let’s see where the naked-eye planets have wandered off to this week. Very early after sunset, Venus might be spotted very low in the southwest by a little past 6 pm. Mars, and Jupiter will be visible this evening, in the east to southwestern sky by 6:30 or 7 pm. Mars will be above Orion in the east-southeast and is pulling away from the Pleiades. Jupiter is brighter than Mars, and will be in the south-southwest, and tonight it’s directly above the crescent Moon. Saturn is below Venus now, so it’s pretty much gone until it reappears in the morning sky in a few months. Mercury is now in the morning sky, after it passed inferior conjunction with the Sun on the 7th, that is, it passed between the Earth and the Sun. It should be briefly visible before sunrise by month’s end.
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




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01/24/2023 – Ephemeris – The “green” comet’s designation is C/2022 E3 (ZTF)
This is Bob Moler with Ephemeris for Tuesday, January 24th. Today the Sun will be up for 9 hours and 29 minutes, setting at 5:40, and it will rise tomorrow at 8:09. The Moon, 3 days past new, will set at 9:26 this evening.
Yesterday, I began covering new comet that’s in our skies. I didn’t mention its name. It’s got an odd one. Its designation is C/2022 E3, which means it was discovered in 2022. E means that it was in the 5th half month of the year, which puts it in early March, and three is the third object in that period. The name that goes along with it is actually the initials ZTF which stand for Zwicky Transient Facility which is actually 2 observatory complexes, one in California and the other one in Chile which looks for things that go bump in the night. Basically, things that change their brightness or movement in the short period of time. They cover the whole sky eventually and get back and see what’s changed. The facility is named after astronomer Fritz Zwicky.
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

01/23/2023 – Ephemeris – New “green” comet C/2022 E3 (ZTF)
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 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.
01/20/2023 – Ephemeris – Gemini’s Castor is six stars orbiting each other
This is Ephemeris for Friday, January 20th. Today the Sun will be up for 9 hours and 21 minutes, setting at 5:34, and it will rise tomorrow at 8:12. The Moon, 1 day before new, will rise at 8:34 tomorrow morning.
At 9 p.m. the constellation of Gemini the twins will be seen high in the east-southeast. The namesake stars of the two lads are the two bright stars at the left of the constellation. Pollux the pugilist, or boxer, is the lower and slightly brighter of the two, while Castor, the horseman, is the other star, or rather a six-star system. In telescopes two close stars may be seen, each is a spectroscopic binary, meaning the lines of two stars can be seen in the spectrum, shifting as they orbit each other. Another faint spectroscopic binary also belongs. Pollux, though a single star, does have at least one planet with over twice the mass of Jupiter orbiting the star. Pollux and Castor are respectively 34 and 50 light years away. Not too far away as stars go.
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

01/19/2023 – Ephemeris – Gemini, twins with a secret
This is Ephemeris for Thursday, January 19th. Today the Sun will be up for 9 hours and 19 minutes, setting at 5:33, and it will rise tomorrow at 8:13. The Moon, 2 days before new, will rise at 7:38 tomorrow morning.
Another famous winter constellation is Gemini. The constellation of Gemini the Twins is visible halfway to the zenith in the east, at the top and left of Orion the hunter, at 9 pm. The namesake stars of the two lads, are the two bright stars at the left end of Gemini, and are high and are due east. Castor is on top, while Pollux is below. From them come two lines of stars that outline the two, extending horizontally 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.
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

Gemini finder animation for the second half of January 2023. It’s dated because Mars is dawdling in Taurus near the Pleiades. Mars is now back to heading eastward once again, after being in retrograde or westward motion as the Earth passed it in early December. Mars will officially enter Gemini in March. Created using Stellarium, and GIMP.
01/18/2023 – Ephemeris – Let’s see where the naked-eye planets have wandered off to this week
This is Ephemeris for Wednesday, January 18th. Today the Sun will be up for 9 hours and 17 minutes, setting at 5:32, and it will rise tomorrow at 8:14. The Moon, 3 days before new, will rise at 6:28 tomorrow morning.
Let’s see where the naked-eye planets have wandered off to this week. Very early after sunset, Venus might be spotted very low in the southwest by 6 pm. Mars, Jupiter and Saturn will be visible this evening, in the east to southwestern sky by 6:30 or 7 pm. Mars will be above Orion in the east-southeast and near the Pleiades. Jupiter is the brightest of the three and will be in the south-southwest., while dimmer Saturn will be very low in the southwest at that time. Saturn, the westernmost of these bright planets, will set around 7:42 this evening. It’s a bit above and left of Venus. Mercury is now in the morning sky, after it passed inferior conjunction with the Sun on the 7th, that is, it passed between the Earth and the Sun. It should be briefly visible before sunrise by month’s end.
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

Venus and Saturn low in the southwest at 6:15 pm tonight, January 18, 2023. Saturn will probably not be visible yet, but Venus should be plenty bright enough. Created using Stellarium.

All the evening planets before Venus sets are in this panorama looking southward from east to west at 7:15 tonight, January 18, 2023. I dropped lines from some of the dimmer constellations. Click on the image to enlarge it. Created using Stellarium.

Telescopic views of Saturn Jupiter and Mars (north up) as they would be seen in a small telescope, with the same magnification. The image of Mars doesn’t show it, but the white north polar cap will appear at the top or north limb of Mars. The planets are shown at 7 pm tonight, January 18, 2023. Apparent diameters: Venus 10.77″ and is 93.5% illuminated; Saturn 15.52″, its rings 36.16″; Jupiter 37.32″. Mars 12.25″. Mars’ distance is71.6 million miles (114.4 million kilometers). The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).