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Ephemeris: 10/17/2024 – Comets look a lot bigger than they actually are
This is Bob Moler with Ephemeris for Thursday, October 17th. Today the Sun will be up for 10 hours and 52 minutes, setting at 6:53, and it will rise tomorrow at 8:02. The Moon, at full today, will rise at 6:53 this evening. | Comet Tsuchinshan-ATLAS will have its greatest competition with the Moon tonight since it’s full. However, in succeeding nights the Moon will get dimmer and also rise later. At 8 PM the comet will be nearly 18° above the west-southwestern horizon with its tail pointing to up into the bit to the left.* What makes comets spectacular is that they contain volatile materials, like frozen gases, water, and carbon compounds. The solid body of the comet, called the nucleus is quite small, from less than a mile to up to 25 miles in diameter, which on the solar system scale is tiny. They live quite happily in the outer solar system where it’s cold. When approaching the Sun the gases sublimate liberating the included dust, producing the tails the comets are famous for.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
* I was able to spot the comet last night at around 8:10 PM but only through binoculars. It was not visible to my unaided eye. However, it was visible in binoculars. It also photographed well with the image showing a lot more than what was visible even through binoculars and the amount of clouds that were actually in the sky. However, the clouds were light and generally did not hinder the comet too much. The photograph of the comet below has been processed to increase its brightness and contrast with the sky.
Addendum
Ephemeris: 10/16/2024 – Where are the naked-eye planets and the comet?
This is Bob Moler with Ephemeris for Wednesday, October 16th. Today the Sun will be up for 10 hours and 55 minutes, setting at 6:55, and it will rise tomorrow at 8:01. The Moon, 1 day before full, will set at 8:11 tomorrow morning.
Let’s take our weekly look at the whereabouts of the naked-eye planets. Venus might be spotted in the West southwest low on the horizon at 7:30 PM, 35 minutes after sunset. It will set at 8:19. Comet Tsuchinshan-ATLAS will be west southwest way above and to the right of Venus. It will set at 9:46 PM. Saturn will be in the southeast at 8 PM. Jupiter will rise at 9:40 PM this evening and be a good object for the small telescope about an hour later. Jupiter and Mars are both mourning planets so they can be seen early in the morning before sunrise. By 7:00 AM tomorrow Jupiter will be high in the southwest while Mars will be high in the South.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 10/15/2024 – Comet Tsuchinshan-ATLAS should be visible this week if clouds allow
This is Bob Moler with Ephemeris for Tuesday, October 15th. Today the Sun will be up for 10 hours and 58 minutes, setting at 6:57, and it will rise tomorrow at 8:00. The Moon, 2 days before full, will set at 6:47 tomorrow morning.
Comet Tsuchinshan-ATLAS has been visible in our evening skies for the last three nights and will be at least bright enough to be seen with the naked eye. And it should be so for most of the rest of the month. However, this week so far has been cloudy, and it will be cloudy until possibly Wednesday night however Thursday and Friday look like the best for viewing of the comet. Of course this is Michigan, so don’t hold me to it. The comet has been pretty much living up to expectations as far as its brightness and the length of its tail. The comet peak brightness which came early last week, when it could only be seen during the daytime, was as bright as the planet Venus. Now that it is headed away from the Sun and the Earth it will rapidly fade.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
What we’ve missed
It was partly cloudy on the evening of 14th, last night. I went out a little after 8 PM to see if I could spot the comet. I could see Arcturus, however I could not spot the comet or the planet Venus. However, I believe someone in our area could have spotted the comet, if they were in the right location.
Ephemeris: 10/14/2024 – The One Who Came From a Shooting Star
This is Ephemeris for Indigenous Peoples Day, Monday, October 14th. Today the Sun will be up for 11 hours and 1 minute, setting at 6:58, and it will rise tomorrow at 7:58. The Moon, 3 days before full, will set at 5:24 tomorrow morning.
I’ll relate it to our comet. Comets are the cause of meteor showers. However, our current comet Tsuchinshan-ATLAS will never produce a meteor shower for us because its orbit doesn’t come close to the Earth’s. The closest it gets is half the distance to the Sun which it did five days ago.
The Anishinaabek have a story about how the Wolverine got its name, in their language, gwiingwa’aage, which means “The One Who Came From a Shooting Star”. An evil star spirit crashed to Earth and created a crater in what is now northern Quebec. Later it filled with water, and sometime later this ill-tempered creature crawled out of it. The University of Michigan’s teams are called the Wolverines, even though the wolverine is not native to Michigan.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 10/11/2024 – Comet Tsuchinshan-ATLAS may be visible as early as tonight
This is Ephemeris for Friday, October 11th. Today the Sun will be up for 11 hours and 10 minutes, setting at 7:04, and it will rise tomorrow at 7:55. The Moon, 1 day past first quarter, will set at 1:22 tomorrow morning.
While I think the first time the spot Comet Tsuchinshan-ATLAS will be tomorrow night, sharp-eyed observers with binoculars might be able to find the comet tonight just about due west near the horizon after 7:30 PM it will be a difficult task being so close to the sun The comet will set at 8:09 PM, however if the tail is bright enough it may still be visible. The comet’s tail should be relatively short since it’s actually pointing back towards us. That may also make the tail somewhat brighter since we’re looking down through the thicker part of the tail rather than through its side. I’ve seen a lot of comets in my time, the first ones in 1957. There were two bright comets that year.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 10/10/2024 – Where did Comet Tsuchinshan-ATLAS come from?
This is Ephemeris for Thursday, October 10th. Today the Sun will be up for 11 hours and 13 minutes, setting at 7:05, and it will rise tomorrow at 7:53. The Moon, at first quarter today, will set at 12:05 tomorrow morning.
The comet Tsuchinshan-ATLAS will get far enough from the direction of the Sun so we can see it in the evening this weekend. It comes from the Oort Cloud of comets in the far reaches of the solar system probably extends maybe three quarters* of the way to the nearest other star to us Alpha Centauri. Somebody figured out that it has an orbital period of around 80,000 years. Every few million years or so a star comes close enough to the Sun to stir up the comets in the Oort Cloud, sending some of them out escaping the Sun and some sent in towards the inner solar system. This of course is one of the latter. No two comets are exactly alike so they’re quite unpredictable. Some have a lot of dust and some are mostly frozen gases.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
* On the radio program I stated a “quarter of the way”.
Addendum
The Oort Cloud is named after Jan Oort, a Dutch astronomer, who proposed a cloud of comets in 1950 as the source of long period comets. The cloud would extend from 2,000 to 200,000 times Earth’s distance from the Sun. The shape of the cloud is roughly spherical. Comet encounters with Jupiter can cause them to become short period comets, or be ejected from the solar system.
Ephemeris: 10/09/2024 – Where are the naked-eye planets this week?
This is Ephemeris for Wednesday, October 9th. Today the Sun will be up for 11 hours and 16 minutes, setting at 7:07, and it will rise tomorrow at 7:52. The Moon, 1 day before first quarter, will set at 10:57 this evening.
Let’s take our weekly look at the whereabouts of the naked-eye planets. Venus might be spotted in the West southwest only 7° above the horizon at 8 PM, 55 minutes after sunset. It will set at 8:23. Saturn will be in the southeast at that time. Saturn may look disappointing in telescopes this year since its rings are nearly edge on and appearing as a line through the planet like it’s stapled onto the sky. Jupiter and Mars will be up in the morning sky, with Jupiter rising about 10:08 PM in the east-northeast. By 7 AM tomorrow, Jupiter will be brighter than any of the winter stars high in the south. Mars, with its reddish hue, will be to the left of Jupiter. Comet Tsuchinshan-ATLAS will be in the western evening sky starting this weekend. It is expected to be quite bright, I’m betting with a broad tail.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 10/08/2024 – Comet Tsuchinshan-ATLAS may be brighter than expected
This is Ephemeris for Tuesday, October 8th. Today the Sun will be up for 11 hours and 19 minutes, setting at 7:09, and it will rise tomorrow at 7:51. The Moon, 2 days before first quarter, will set at 10:00 this evening.
You are going to hear a lot about a bright comet visible in the evening starting this weekend. The comet with a long name Tsuchinshan-ATLAS will begin to be visible in the evening sky, and it will be very bright. It will be the brightest comet we’ve had in some time visible in the Northern Hemisphere since Comet Hale-Bopp in 1997. The reason for this comet’s great brightness is that the comet is passing between the Earth and the Sun. This comet is very dusty with an extensive dust tail. Since the comet is passing between the Earth and Sun the dust scatters sunlight in a forward direction like seeing sunbeams through holes in the clouds near sunset. This is making the comet brighter than originally predicted.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 10/07/2024 – Comet Tsuchinshan-ATLAS will be visible starting Saturday Night
This is Ephemeris for Monday, October 7th. Today the Sun will be up for 11 hours and 22 minutes, setting at 7:11, and it will rise tomorrow at 7:50. The Moon, 3 days before first quarter, will set at 9:15 this evening.
In January of last year a Chinese observatory discovered a comet which was subsequently lost. A month and a half later another observatory in South Africa rediscovered it. That’s why the comet is named, Tsuchinshan-ATLAS after the two observatories. It was soon learned that the comet had a chance of becoming visible to the unaided eye in late September and October 2024, this month. Despite having a dimming episode earlier this year the comet promises to be naked eye and possibly even spectacular. The comet is moving from the south to the north and in a direction counter to the orbiting planets around the Sun. We will begin to see it low in the West after sunset starting Saturday.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
The comet will pass almost directly between the Earth and the Sun on the evening of the 9th. It’ll be about halfway between the Earth and the Sun at that point. It should be picked up by the Solar and Heliospheric Observatory satellite (SOHO) which is orbiting the Earth-Sun L1 Lagrange point a million miles sunward from the Earth with its C3 coronagraph*. Then the comet’s tail should be pointing almost directly at the Earth. As the comet swings out away from the Sun it will also be more rapidly moving away from Earth. This is because the comet has an orbit that is counter to that of the orbits of the Earth and the rest of the planets around the Sun and will rapidly fade as it increases its distance.
A note on the discovery designation: C/2023 A3 is C for comet; 2023, the year of discovery; A3, third object reportedly discovered in the first half of January.
The SOHO Real-time GIF Movies webpage is: https://soho.nascom.nasa.gov/data/realtime/gif/. Select LASCO/C3. It provides a time-lapse image of the Sun’s corona taken at hourly intervals for about the last 4 days.
Ephemeris: 10/04/2024 – GTAS meeting & star party tonight
This is Bob Moler with Ephemeris for Friday, October 4th. Today the Sun will be up for 11 hours and 31 minutes, setting at 7:16, and it will rise tomorrow at 7:46. The Moon, 2 days past new, will set at 7:51 this evening. | The Grand Traverse Astronomical Society will host its October meeting tonight at 8:00 PM at Northwestern Michigan College’s Joseph H Rogers Observatory, featuring the society’s Library Telescope program. For over five years now the society has given small telescopes to a number of local libraries and branches to lend out. It has been quite successful. After the meeting, about 9 PM if it’s clear, there will be viewing of the heavens through the observatory’s telescopes, featuring Saturn and the wonders of the Milky Way, including nebulae, open and globular star clusters, containing hundreds to hundreds of thousands of stars. The observatory is located on Birmley Rd. South of Traverse City between Garfield and Keystone roads.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
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