Archive
Ephemeris: 01/26/2024 – In astronomy “dark” means we can’t see it
This is Ephemeris for Friday, January 26th. Today the Sun will be up for 9 hours and 33 minutes, setting at 5:42, and it will rise tomorrow at 8:07. The Moon, 1 day past full, will rise at 6:37 this evening.
What does the word “dark” mean? In astronomy the word dark means something we cannot see. In ages before 1959 we could not see the backside of the moon, so people got to calling it the dark side of the Moon. All changed in 1959 when a Soviet spacecraft went around behind the moon it took photographs of it. The two contenders for dark things in astronomy are now dark matter and dark energy. Dark matter is something that has a gravitational effect on the galaxies that it surrounds, but we can’t see it. Also, the expansion of the universe appears to be accelerating, where we would expect it to be decelerating because of gravitational forces of all the galaxies in it. We call that cause dark energy. And we don’t know what either is.
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
Two possible causes of Dark Matter are in the running, WIMPs, and of course MACHOs. WIMPs are Weakly Interacting Massive Particles, while MACHOs are the bit more tortured acronym Massive Astrophysical Compact Halo Objects. Whatever they are they don’t interact much with themselves or ordinary matter, neither emitting light or any other radiation, or block it. However, they have mass and warp spacetime, distorting the shape of galaxies seen behind them. They also make galaxies seem to be more massive than their starlight would make them appear, and other effects.
Ephemeris: 01/24/2024 – Where have the planets wandered off to this week?
This is Ephemeris for Wednesday, January 24th. Today the Sun will be up for 9 hours and 29 minutes, setting at 5:39, and it will rise tomorrow at 8:09. The Moon, 1 day before full, will set at 8:36 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week. Three of those five planets are now easily visible. Saturn and Jupiter are the evening planets. Saturn is getting harder to spot low in the west-southwest, setting at 8:19 pm. Jupiter will move from high in the south to low in the west by midnight, and will set in the west-northwest at 1:40 am. Venus, the brilliant morning star, will rise in the east-southeast at 6:09 am, and be a brilliant beacon in the morning, shining in the southeast before the bright morning twilight claims it around 8 am. Mercury, which rises by 7:03 am might just be visible below and left of Venus by 7:30 am.
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: 01/22/2024 – The Dog Star’s little buddy
This is Ephemeris for Monday, January 22nd. Today the Sun will be up for 9 hours and 24 minutes, setting at 5:37, and it will rise tomorrow at 8:11. The Moon, 3 days before full, will set at 7:14 tomorrow morning.
Sirius is the brightest nighttime star and is located low in the southeast at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius on Tuesday, but there is another star in the Sirius system that is practically invisible due to Sirius’ dazzling glare. Its name is Sirius B, nicknamed the Pup, alluding to Sirius’ Dog Star title. The tiny star was suspected as far back as 1834 due to Sirius’ wavy path against the more distant stars in the sky. Sirius and the Pup have 50-year orbits of each other. The Pup was first seen in 1862. It was the first of a new class of stars to be discovered, white dwarfs. The Pup is a dying star with the mass of the Sun, collapsed down to the size of the Earth after running out of hydrogen fuel in its core.
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: 01/19/2024 – Finding the Dog Star
This is Bob Moler with Ephemeris for Friday, January 19th. Today the Sun will be up for 9 hours and 18 minutes, setting at 5:33, and it will rise tomorrow at 8:13. The Moon, 2 days past first quarter, will set at 3:59 tomorrow morning.
In the evening, the great constellation of Orion the hunter can be seen to slowly move from the south-east to the south. Its large rectangle of bright stars is easily visible, even with a full moon. The three stars in a straight line, his belt, tilt downward to the left to a very bright star merrily twinkling lower in the sky. This star is called Sirius, also known as the Dog Star because it’s in the heart of Orion’s larger hunting dog, Canis Major. It is an arc light white star as seen in binoculars or telescope. It is the brightest star in the night sky, and a neighboring star, just twice the distance of the closest star to the Sun at 8.6 light years. Its name, Sirius, has nothing to do with a dog, but is from the Greek meaning scorching for its brightness and sparkling, due to its intense twinkling.
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: 01/18/2024 – A quick guide to Jupiter for the small telescope
This is Ephemeris for Thursday, January 18th. Today the Sun will be up for 9 hours and 16 minutes, setting at 5:31, and it will rise tomorrow at 8:14. The Moon, 1 day past first quarter, will set at 2:43 tomorrow morning.
Jupiter is the largest planets and is generally the largest appearing planet in a telescope. Venus appears a bit larger than Jupiter only for about four months when it’s the closest it gets to us. There’s always something going on with Jupiter and its 4 Galilean moons which appear to shuffle back and forth from one side to the other of the planet. Jupiter has cloud bands which run parallel to its equator and to the plane of the moon’s orbits. And it has the Great Red Spot, but that spot is not easily visible in small telescopes. Back in the 1950s it was big and brick red. It is since lost a great deal of its redness and size. The moons can hide behind Jupiter or in its shadow or cross in front of the planet. Tonight Jupiter will appear below and right of the Moon.
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: 01/17/2024 – Where have the naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, January 17th. Today the Sun will be up for 9 hours and 14 minutes, setting at 5:30, and it will rise tomorrow at 8:15. The Moon, at first quarter today, will set at 1:28 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week. Four of those five planets are now visible. Saturn and Jupiter are the evening planets. Saturn can be seen moving from low in the southwest to setting in the west-southwest at 8:42 pm. Jupiter, left of the Moon tonight will move from high in the south to set in the west-northwest at 2:05 am. Venus, the brilliant morning star, will rise in the east-southeast at 5:58 am, and be a brilliant beacon in the morning, shining in the southeast before the bright morning twilight claims it around 8 am. Mercury will also be visible below and left of Venus, and should be visible by 7:30 am. Mars is below left of Mercury, but really is too dim to be seen.
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: 01/16/2024 – Watch Saturn’s rings continue to narrow this year.
This is Ephemeris for Tuesday, January 16th. Today the Sun will be up for 9 hours and 12 minutes, setting at 5:29, and it will rise tomorrow at 8:15. The Moon, 1 day before first quarter, will set at 12:12 tomorrow morning.
After the Moon, the next targets for the small telescope are the planets. Saturn is getting pretty low in the southwest now so there’s only about another month when it’s really visible in steady skies. Of course Saturn has those beautiful rings which are now getting very thin and by the end of March next year they will be edge on to us and then begin to open up through the rest of 2025. One’s first impression of Saturn is generally that besides the rings it’s really tiny. It averages almost a billion miles from the Earth, and even though it’s the second-largest planet it looks very tiny at that distance. Saturn’s largest moon Titan can be seen near the planet it is the second-largest moon in the solar system.
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: 01/15/2024 – The Moon is a great first target for that new telescope
This is Bob Moler with Ephemeris for the Martin Luther King Jr. Holiday, Monday, January 15th. Today the Sun will be up for 9 hours and 11 minutes, setting at 5:27, and it will rise tomorrow at 8:16. The Moon, 2 days before first quarter, will set at 10:55 this evening.
The Moon is a great first target for that Christmas telescope. Over the weekend we began a new lunar month so that the Moon appears as a crescent in the southwestern sky after sunset. The first time I looked at the Moon with the telescope or looked at anything in the sky, actually, I found it very difficult to aim the telescope correctly. The field of view of the telescope is very small compared to what you can see with the naked eye. Always start with the lowest power eyepiece because it gives the widest field of view for finding what you’re looking for. It does take a little practice to learn how to aim a telescope, but the moon is a wonderful object to look at because it’s really big and very bright.
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: 01/12/2024 – Mercury is at greatest western elongation from the Sun today
This is Ephemeris for Friday, January 12th. Today the Sun will be up for 9 hours and 6 minutes, setting at 5:24, and it will rise tomorrow at 8:17. The Moon, 1 day past new, will set at 6:49 this evening.
The planet Mercury is reaching its greatest western elongation or separation west of the Sun today at a 23.5 degrees angle, which is pretty good actually, although the angle above the horizon where we see Mercury at this point in the year is not the best. However, Venus can be used to spot Mercury because Mercury will be to the lower left of Venus. Binoculars are always helpful in spotting Mercury for the first time. From now until about a week from now Mercury will not move very much in relationship to Venus, but it will be getting somewhat brighter as its phase goes from half illuminated to more gibbous towards full. Early in the spring it will be seen in the evening sky, at a little bit better angle above the horizon, although it will be it will not be as far away from the Sun. Created using Stellarium and GIMP.
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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