Archive
Ephemeris: 02/26/2024 – The angle of the rising and setting planets from the Sun vary with the seasons
This is Bob Moler with Ephemeris for Monday, February 26th. Today the Sun will be up for 10 hours and 59 minutes, setting at 6:25, and it will rise tomorrow at 7:24. The Moon, 2 days past full, will rise at 8:44 this evening.
In late winter and early spring dark skies return within a few days after the full Moon. Indeed, this is the first day after the full moon, which was on Saturday morning, that we have dark skies. Well for 40 minutes before the Moon rises. This is because the ecliptic which is the Sun’s path in the sky is as close to vertical as it can get for us. It shows planets near the Sun and the area of the full moon as steeply inclined to the horizon as possible. Twelve years ago this month when my wife and I were on a Hawaiian cruise, I was aboard ship looking at the sky after sunset and was amazed to see Jupiter and Venus* vertically aligned in the west. It was because we were located around the Tropic of Cancer and near the equinox, so the ecliptic was actually vertical after sunset. It was quite a jolt to see that. So this time of year we can see planets close to the sun at sunset and the moon to go away after full rapidly.
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.
* On the broadcast I said Jupiter and Saturn, relying on my memory. As can be seen below, it was Jupiter and Venus.
Addendum
Ephemeris: 02/21/2024 – Where have the naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, February 21st. Today the Sun will be up for 10 hours and 44 minutes, setting at 6:19, and it will rise tomorrow at 7:32. The Moon, 3 days before full, will set at 7:09 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week, and see what planets are left. Saturn, and Mercury are gone, being too close to the Sun to be visible. Jupiter will be in the west-southwest at 8 this evening. It will set at 12:11 am in the west. Jupiter will be visible in the evening for only about two more months. Venus, the morning star, will rise in the east-southeast at 6:33 am, but its brilliance is diminished by the bright twilight and its low position in the sky. It will be very low in the southeast at 7 am. This might be our first chance to spot Mars in the morning sky because tomorrow morning it will be just below Venus by about 1 1/2 moon diameters. A pair of binoculars may be needed to spot it.
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
Jupiter’s missing moon is Io, which is behind the planet. It will reappear at 9:43 pm away from the planet because until then it’ll still be in Jupiter’s shadow. At 10:02 pm Europa will begin to transit across the face of the planet.
The ” symbol means seconds of arc (1/3600th of a degree). Created using Cartes du Ciel (Sky Charts) and GIMP.
Ephemeris: 02/20/2024 – Schiller, an odd lunar crater
This is Ephemeris for Tuesday, February 20th. Today the Sun will be up for 10 hours and 41 minutes, setting at 6:17, and it will rise tomorrow at 7:34. The Moon, halfway from first quarter to full, will set at 6:39 tomorrow morning.
The moon tonight is in its gibbous phase, with more than half of it being illuminated by the Sun. In binoculars or a small telescope, looking at the bottom part of the moon, near the South Pole. All the craters appear to be elongated, foreshortened actually, because the moon is spherical. But one crater stands out as being more elliptical than the rest it’s called Schiller. It’s about 111 miles long, and much less in the other direction. It still appears elongated when seen from overhead by a spacecraft. It looks like the footprint of a long narrow shoe. It is either the result of a low angle hit from the asteroid or two overlapping low angle asteroid craters. I suspect the latter, though I have no expertise in the matter.
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: 02/16/2024 – The Moon will appear near the Pleiades tonight
This is Ephemeris for Friday, February 16th. Today the Sun will be up for 10 hours and 29 minutes, setting at 6:12, and it will rise tomorrow at 7:40. The Moon, at first quarter today, will set at 3:03 tomorrow morning.
The moon will pass south, or below, the star cluster called the Pleiades, or Seven Sisters, this afternoon. By this evening the Pleiades will be seen to the lower right of the Moon. However, you will need a pair of binoculars to see them, because the first quarter Moon is quite a bit brighter than the stars of the Pleiades. The moon will again pass the Pleiades in March on the 14th, where the Pleiades will appear above and left of the Moon. And again, on April 11th, where the Moon will pass south of the Pleiades during the day, and the cluster will be to the lower right of the Moon by evening. They will appear closest together in our evening sky on May 8th. Unfortunately, they will be low in the sky in the west at sunset.
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: 02/15/2024 – Viewing the Moon tonight
This is Ephemeris for Thursday, February 15th. Today the Sun will be up for 10 hours and 26 minutes, setting at 6:10, and it will rise tomorrow at 7:42. The Moon, 1 day before first quarter, will set at 1:48 tomorrow morning.
Let’s look at the Moon again this evening. The moving terminator or sunrise line on the Moon has moved westward, though it looks like eastward to us. It shows Mare Crisium, or Sea of Crises, near the Moon’s edge, which is surrounded by the bright highlands, and to the left and below is the Sea of Fertility. Above that is Mare Tranquillitatis, where the Apollo 11 spacecraft Eagle landed, and below Tranquility are two small dark areas that look like seas, but only the bottom one is, it’s the Sea of Nectar, Mare Nectaris. Between it and Tranquility is the Bay of Roughness or Sinus Asperitatis, which sounds better in the original Latin.
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
Translations of some lunar feature names according to Virtual Moon Atlas
Lacus Somniorum – Lake of Dreams
Mare Crisium – Sea of Crises
Mare Fecunditatis – Sea of Fertility
Mare Nectaris – Sea of Nectar
Mare Serenitatis – Sea of Serenity
Mare Tranquillitatis – Sea of Tranquility
Sinus Asperitatis – Bay of Roughness
Ephemeris: 02/14/2024 – A Valentine’s Day look at the bright planets
This is Ephemeris for Valentine’s Day and Ash Wednesday, Wednesday, February 14th. Today the Sun will be up for 10 hours and 24 minutes, setting at 6:09, and it will rise tomorrow at 7:43. The Moon, 2 days before first quarter, will set at 12:31 tomorrow morning.
Let’s find out where the naked -eyed planets have wandered off to this week, and see what planets are left. Saturn, for all practical purposes, is gone, setting an hour after the sun. Jupiter will be in the southwest at 7:30 this evening, above and left to the crescent moon. It will move to the low west -northwest by midnight and will set at 12:30 am. Venus, the morning star, will rise into the east-southeast at 6:30 am, but its brilliance is diminished by the bright twilight and its low position in the sky. It will be very low in the southeast at seven am. Being Ash Wednesday, Easter is 46 days away. But Lent has 40 days. The six Sundays in Lent don’t count.
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: 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: 02/09/2024 – Two lunar months until the total solar eclipse!
This is Ephemeris for Friday, February 9th. Today the Sun will be up for 10 hours and 9 minutes, setting at 6:02, and it will rise tomorrow at 7:50. The Moon is new today, and won’t be visible.
Today marks two lunar months before the April 8th total eclipse of the Sun. It will be partial here when nearly 90% of the Sun will be blocked by the Moon. The best place to see the total part of the eclipse is on the line from Texas through Indiana, Ohio and ending in Maine. We will not have another total eclipse visible in the continental United States until 2044 and again in 2045. The 2044 total eclipse path will only touch North Dakota and Montana at sunset, after descending south from Canada*. The eclipse of 2045 will have a path across the United States much like, but south of, the path in of the August 21st 2017 eclipse. This time passing from Northern California to Northern Florida. So it’s going to be a long drought of total solar eclipses unless one travels to other continents or go on an eclipse cruise.
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.
* On the radio program I have the Moon’s shadow going the other way. This is a rare eclipse where the Moon umbral shadow (the part that produces totality) starts and ends at local sunset.
Addendum
I will have Ephemeris Extra posts soon about how to observe the eclipse safely.
Ephemeris: 02/08/2024 – Up the river
This is Ephemeris for Thursday, February 8th. Today the Sun will be up for 10 hours and 7 minutes, setting at 6:00, and it will rise tomorrow at 7:52. The Moon, 1 day before new, will rise at 8:09 tomorrow morning.
One of the more obscure constellations around is Eridanus, which depicts a river. The river starts near the lower right corner of Orion, near the bright star Rigel and flows to the right then down near the southwestern horizon, then it meanders along the horizon to the south before turning below the horizon. One has to travel to the far south to see the southern terminus of the river, the bright star Achernar. Writers over the ages have seen here the Nile and the Earth circling river Ocean of the flat earth days. Achernar is actually two stars, the brightest was discovered to be the flattest star known, due to its rapid spin. The dimensions of Achernar A has been determined to be twice as wide across its equator than from pole to pole. It’s 139 light years away.
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: 02/07/2024 – Where have the naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, February 7th. Today the Sun will be up for 10 hours and 4 minutes, setting at 5:59, and it will rise tomorrow at 7:53. The Moon, 2 days before new, will rise at 7:32 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week. Three of those five planets are now visible. Saturn and Jupiter are the evening planets. Saturn is getting harder to spot very low in the west-southwest, nearly succumbing to evening twilight, setting at 7:32 pm. Jupiter will move from high in the south-southwest to low in the west by midnight, and will set in the west-northwest at 12:53 am. Venus, the morning star, will rise in the east-southeast at 6:25 am, but its brilliance is diminished by the bright twilight and its low altitude in the sky. As we advance through winter into spring Venus is going to be harder to spot before sunrise for two reasons, Venus is getting closer to the Sun, and it is appearing more to the right side of the Sun, than above it.
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
Jovian satellite interactions with Jupiter and its shadow visible for Michigan and longitudes around 85 degrees west:
- 7:03 pm Europa’s transit across the face of Jupiter ends.
- 7:18 pm Europa’s shadow begins to cross Jupiter’s face.
- 9:38 pm Europa’s shadow leaves Jupiter’s face.
- 9:42 pm Ganymede starts an occultation by Jupiter (hides behind it).
- 12:47 am Ganymede’s occultation ends.
Bob Moler's Ephemeris Blog 