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Ephemeris: 02/13/2024 – View the Moon tonight
This is Ephemeris for Fat Tuesday, February 13th. Today the Sun will be up for 10 hours and 21 minutes, setting at 6:07, and it will rise tomorrow at 7:45. The Moon, 3 days before first quarter, will set at 11:12 this evening.
The moon tonight appears to be a beautiful crescent, a four-day-old moon, or three days before first quarter. On it are two dark seas visible, the small sea Mare Crisium, or Sea of Crises, is easily spotted surrounded by bright highlands near the moon’s limb, or edge. The larger Mare Fecunditatis (Fertility) is left of it. At the edge of the Sea of Fertility at the Terminator, one can see in binoculars, or a small telescope, a tiny keyhole-shaped crater which stands out. It really does look like a tiny keyhole, but it’s two craters slightly overlapping each other. Both are named after Johannes Gutenberg, the inventor of the movable-type printing press. The big crater is Gutenberg. The second is Gutenberg C.
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
Ephemeris: 01/25/2024 – Where is the full moon in winter?
This is Ephemeris for Thursday, January 25th. Today the Sun will be up for 9 hours and 31 minutes, setting at 5:41, and it will rise tomorrow at 8:08. The Moon, at full today, will rise at 5:30 this evening.
The exact time that the Moon will be full, at least to the nearest minute is 12:54 this afternoon. Have you ever noticed the placement of the full moon in the sky between winter and summer? The full moon near the winter solstice moves very high at midnight, while the full moon near the summer solstice is seen quite low in the south. For the Moon to be full, it must be nearly opposite the Sun in the sky, so we see it fully illuminated as the Sun does. The Moon’s orbit is close to the Sun’s apparent path in the sky, the ecliptic, which is the projection of the Earth’s orbit of the Sun. So the Moon now is near, and actually a bit north of, where the Sun will be 6 months from now in mid to late July.
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
Ephemeris: 01/23/2024- The “dark” side of the Moon is its brightest side
This is Ephemeris for Tuesday, 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 before full, will set at 8 o’clock tomorrow morning.
In a couple of days the far side of the Moon will become the dark side for real. It’ll be night when the near side of the moon becomes fully illuminated, the far side will be a night. The far side of the moon actually gets more sunlight than the near side of the moon because it does not suffer solar eclipses. The lunar solar eclipse occurs when we see a lunar eclipse. The Sun is blocked from shining on the Moon. The totality of a lunar solar eclipse lasts much longer than a few minutes that we get when the Moon totally blocks the Sun, the length of totality for the Moon’s solar eclipse can last several hours. The far side of the moon does not see eclipses, and when fully illuminated at what we call new moon it is a quarter of a million miles closer to the Sun than Earth.
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
Ephemeris: 12/18/2023 – The Moon tonight
This is Bob Moler with Ephemeris for Monday, December 18th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:03, and it will rise tomorrow at 8:15. The Moon, 1 day before first quarter, will set at 11:50 this evening.
Tonight’s Moon is just about exactly one day before first quarter it’s a six-day-old Moon. Each quarter of the revolution of the moon is just about one week. A lunar month comes out to 29 1/2 days which is a little bit more than 28 days which should be four weeks. That’s pretty close. The illuminated part of the moon that we’re looking at first quarter I consider the most interesting half of the Moon with a good mixture of lowlands which are the seas which are the dark grayer parts of the Moon and the highlands which are very roughly cratered, and are actually higher than the lowlands, or the seas. So if you could put water on the Moon without evaporating it, this is where the water would be. Early telescopic astronomers did think that’s where the water was. Of course the Moon has no atmosphere and the water would just evaporate.
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
Ephemeris: 11/20/2023 – Observing the Moon tonight
This is Ephemeris for Monday, November 20th. Today the Sun will be up for 9 hours and 24 minutes, setting at 5:10, and it will rise tomorrow at 7:47. The Moon, at first quarter today, will set at 12:42 tomorrow morning.
The moon was exactly first quarter at 5:50 this morning. By this evening it will be slightly gibbous. If I want to see the most detail on the Moon of any kind, the best time to observe it is within a few days of first quarter. More craters are visible, and other features are easier to see then. The southern part of the Moon or the bottom part, as we see it, is littered with craters. It’s called the lunar highlands, and they are really higher than the darker and flatter regions, which are called seas. There is no water in them but if the Moon did have water, that’s where it would be. There are a couple of mountain ranges which are actually the edges of a sea called Mare Imbrium that are just coming into view. They show up nicely with their shadows. It’s shadows that make the detail on the moon stand out, because the Moon basically is darker gray on lighter gray, so the only contrast is with shadows. That’s why I find the full moon to be so disappointing. No shadows.
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.
Ephemeris: 09/28/2023 – Tomorrow night’s full moon is the Harvest Moon
This is Ephemeris for Thursday, September 28th. Today the Sun will be up for 11 hours and 52 minutes, setting at 7:29, and it will rise tomorrow at 7:38. The Moon, 1 day before full, will set at 7:43 tomorrow morning.
Tomorrow night’s full moon is the Harvest Moon. It is the most famous of the named full moons, and was very useful in the days before electric lights. The reason is that the Moon, around the time it is full, doesn’t advance its rising time very much from night to night, effectively adding its light to twilight to allow more time to gather in crops. This is because the Moon is moving north as well as eastward. The farther north it is, the longer it stays up and retards the advance in rise times. On average, the Moon rises 50 minutes later each night. This week, the interval is down near 22 minutes advance in moonrise times per day, extending twilight and the amount of time each day to harvest the crops for a few more days.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
My interest in the Harvest Moon is not in harvesting the crops. I just have a little garden, so it doesn’t take that long to pick tomatoes or whatever. But as an amateur astronomer I’m more interested in deep sky objects than I am in planets. Deep sky objects or DSOs are objects beyond the solar system and are usually very dim, which requires dark skies to view them. Near the Harvest Moon and even in August near the full moon it takes nearly a week for that @#$%^&* Moon to get the heck out of the evening sky, so I don’t have to stay up till after midnight to see anything. That’s I why have this interest in the Harvest Moon. Know your enemy!
Ephemeris: 09/21/2023 – Star party in Thompsonville, MI tomorrow or Saturday
Sorry for the delay, but we had a star party event as part of a Child & Family Services of Northwestern Michigan event last evening and I forgot this post. The radio program were broadcast at its scheduled times. Any late additions are in italics.
This is Ephemeris for Thursday, September 21st. Today the Sun will be up for 12 hours and 13 minutes, setting at 7:42, and it will rise tomorrow at 7:29. The Moon, 1 day before first quarter, will set at 10:51 this evening.
Tomorrow night, if it’s clear, members of the Grand Traverse Astronomical Society will hold a twilight talk and a star party at the Betsie Valley District Library in Thompsonville, Michigan. It starts at 7 p.m. with a talk about the upcoming solar eclipses by member Dan Dall’Olmo. There will be a minor partial solar eclipse next month on the 14th, and a much greater partial eclipse April 8th. The total part of the April eclipse can be seen less than a day’s drive away in Indiana and Ohio. Featured will be the first quarter Moon and some of the stars of the waning nights of summer. If Friday night is cloudy the event will be postponed until Saturday night. (It’s looking like Saturday night might be the better night, but a decision can be made as late as 5 pm the day of the event) The season of fall starts Saturday with the autumnal equinox.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
Ephemeris: 08/24/2023 – The Moon will pass in front of the star Antares tonight
This is Ephemeris for Thursday, August 24th. Today the Sun will be up for 13 hours and 38 minutes, setting at 8:33, and it will rise tomorrow at 6:56. The Moon, at first quarter today, will set at 12:11 tomorrow morning. | Tonight the Moon is going to pass in front of the bright reddish star in Antares in Scorpius scorpion. The event is called an occultation, and it is the only one of the monthly occultations which we’re going to be able to see in this series that began last month and will extend to August 2028. Antares will disappear at the lower left edge of the dark or night part of the Moon at approximately 10:28 pm* this evening, and it’ll stay hidden until 11:32 pm* when it will pop out on the lower right edge of the bright part of the Moon. Start looking for Antares early, probably with binoculars, because the Moon will be quite bright and might overpower Antares when viewed by the naked eye. Hoping for clear skies tonight.
*The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location. For other locations a planetarium computer app like Stellarium can be used to graphically predict occultation timings within a few minutes. Check your planetarium app, and set it to use Topocentric coordinates. In Stellarium, the selection is in the Configuration window, Tools tab. Check everything under Topocentric coordinates. That way the position of the Moon in the sky will be based on the chosen location, rather than the center of the Earth.
Addendum
A time-lapse prediction of the occultation of Antares by the Moon based on Stellarium imagery. In the actual occultation Antares will wink out and on suddenly. Antares is a double star, with a 5th magnitude companion. It should wink out and in 9 seconds before the main first magnitude star.
World map showing the area where the occultation of Antares can be visible. It is the area bounded by the white line, the red dotted line and the floppy figure 8 is the area where the occultation is visible. The red line shows that the area near that part of the line is where the occultation occurs during daylight the solid white line on the bottom encloses there is where the occultation will be seen at night. Michigan is close to that cyan line and so the occultation will occur near moonset. Credit: Occult 4 app.
Ephemeris: 08/21/2023 – Looking at a trio of lunar craters tonight
This is Ephemeris for Monday, August 21st. Today the Sun will be up for 13 hours and 47 minutes, setting at 8:39, and it will rise tomorrow at 6:53. The Moon, 3 days before first quarter, will set at 10:48 this evening.
The crescent Moon tonight has what looks like a chain of three large craters near the terminator, visible in a low power telescope. The terminator is the line between day and night. Before the full moon, it’s the sunrise line. On closer inspection, these craters are of different ages. The north crater Theophilus, 63 miles in diameter and one of my favorite craters, looks relatively fresh. It’s not, it’s somewhat older than a billion years. The crater just south of it is Cyrillus, about the same size, which is almost 4 billion years old. Theophilus slightly overlaps Cyrillus. A bit farther south is Catharina, which again is about the same size and age range as Cyrillus, but seems more broken down than the other.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
A closer look at these three craters for tonight at 10 pm. Created using Virtual Moon Atlas, LibreOffice Draw and GIMP.
Ephemeris: 07/31/2023 – August’s Blue Moon
This is Ephemeris for Monday, July 31st. Today the Sun will be up for 14 hours and 42 minutes, setting at 9:10, and it will rise tomorrow at 6:28. The Moon, 1 day before full, will set at 5:45 tomorrow morning.
In August, we are going to have two full moons this year and by most modern reckoning the second full moon is called a Blue Moon, even though that’s not the color of the Moon, which looks like normal although both of these moons in August will be supermoons, so they’ll be a little bit larger than average. However, there is nothing to compare them to, so there’s no way of determining this visually for yourself. The older definition of blue moon is the third full moon in a season that has four full moons. Being a purist, I prefer the latter definition, but I seem to be in a minority. The months of our calendar are a result of Roman politics and superstition, an arbitrary construct. So are time zones by modern politicians. Some time zones could have a blue moon, and some not.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
Bob Moler's Ephemeris Blog 