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10/20/2022 – Ephemeris – Halley’s Comet returns… in little bitty pieces
This is Bob Moler with Ephemeris for Thursday, October 20th. Today the Sun will be up for 10 hours and 44 minutes, setting at 6:49, and it will rise tomorrow at 8:06. The Moon, 3 days past last quarter, will rise at 3:36 tomorrow morning.
Halley’s Comet is back! (Pronounced Hawley’s) Well sorta. In the form of the Orionid meteor shower. Bits of Halley’s Comet from previous passes by the Earth’s orbit make their twice-yearly show in our skies as these bits collide with the Earth’s atmosphere. Halley’s orbit passes close to the Earth’s orbit at points where the Earth is around May 6th and again near October 21st. Light dust and ionized gas get blown back into the tail of the comet. Heavier particles will roughly follow in the comet’s orbit. The radiant, a spot above the constellation Orion and below Gemini from which they will seem to come, will rise around 11 pm. So view them any time after that as their numbers will increase until the Moon rises both tonight and tomorrow nights.
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
The Orionid Radiant is high in the south at 5 a.m. this weekend. Created using Stellarium.
Halley’s Comet orbit with the orbits of the inner planets showing the points at which the debris from the comet intersect with the Earth’s orbit, causing meteor showers. Click on the image to enlarge it. Diagram credit JPL Small-Body Database Browser with my annotations.
05/05/2022 – Ephemeris – Halley’s Comet returns… in pieces
This is Ephemeris for Cinco de Mayo, Thursday, May 5th. Today the Sun will be up for 14 hours and 25 minutes, setting at 8:52, and it will rise tomorrow at 6:25. The Moon, 3 days before first quarter, will set at 1:53 tomorrow morning.
The Eta Aquariid meteor shower will reach peak at about 4 am, tomorrow morning. However, the radiant, the apparent source of the meteor streaks, doesn’t rise until 3:15 am. If you’re waiting to see the return of Halley’s Comet, you needn’t wait until the main body of the comet returns in 2061. Halley’s Comet has made many passes of the inner solar system in recorded history, and more before that, returning to the inner solar system every 76 years or so, before returning to its frigid home beyond Neptune. It’s closest pass to the Sun, called perihelion, is inside Venus’ orbit. On the way in and out, it passes close to the Earth’s orbit. It has left a trail of debris, which we pass through in May and again in October.
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
The Eta Aquariid meteor shower radiant as it will be apparent tomorrow morning at 4:30 or at the beginning of nautical twilight. The radiant isn’t a ting that can be seen, but the point from which all the meteors of this shower can be traced back to. The funny looking lower case “n” is the Greek letter eta. The shower is named for the star seen just above the radiant, which is in the center of a small triangle of stars that make up Aquarius’ water jar. Click on the image to enlarge it. Created using Stellarium.
05/04/2021 – Ephemeris – We cross Halley’s Comet debris this week
This is Bob Moler with Ephemeris for Tuesday, May 4th. Today the Sun will be up for 14 hours and 23 minutes, setting at 8:51, and it will rise tomorrow at 6:26. The Moon, 1 day past last quarter, will rise at 4:20 tomorrow morning.
The Eta Aquariid meteor shower will reach their peak for us Thursday morning the 6th. The Eta Aquariids are caused by bits of Halley’s Comet, passing the Earth’s orbit heading out from the Sun. The Orionids of late October are debris of Halley’s comet passing the Earth’s orbit heading in toward the Sun. The Eta Aquariids are named for the star nearest the radiant of the meteor shower. The constellation of Aquarius has many shower radiants, which is why the shower is named for a star in Aquarius. The radiant rises shortly before 3:30am and astronomical twilight begins an hour later. There’s perhaps another half hour of visibility after that. The peak will occur Thursday morning where 20 meteors per hour or more might be seen.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
two other minor meteor showers are active then with only a handful of meteors an hour
compared to the Eta Aquariids’ somewhat higher rates. The funny looking “n” character
next to Aquariid is the Greek letter Eta. Chart created using Stellarium.
the inner solar system, and the Eta Aquariids when it’s leaving.
Credit my LookingUp program.
04/30/2020 – Ephemeris – See bits of Halley’s Comet in the morning crashing into the Earth’s atmosphere
This is Bob Moler with Ephemeris for Thursday, April 30th. Today the Sun will be up for 14 hours and 13 minutes, setting at 8:47, and it will rise tomorrow at 6:32. The Moon, at first quarter today, will set at 3:47 tomorrow morning.
Do you remember seeing Halley’s Comet back in 1986? The actual pronunciation is “Hawley’s”, according to Sir Edmund’s contemporary Samuel Pepys. The reason I asked is whether you saw it in 1986 or are young enough to live long enough to see it in 41 years, we all have a twice yearly chance to see bits of Halley’s Comet, shed in previous returns through the inner solar system and strewn along its orbit, burn up in Earth’s atmosphere as the Eta Aquariid meteor shower going on now, or the Orionids in late October. The time to see the meteor shower is in the early morning after the Moon sets. That’s after 3:47 a.m. tomorrow morning and 4:22 Saturday morning. Astronomical twilight starts about 4:40 a.m. It will probably be 5 a.m. before it really interferes. With the meteors all over the sky, coming from the southeast.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Eta Aquariid radiant at the peak of the shower. The radiant moves slowly to the east with time. Credit: my LookingUp program.
Halley’s Comet orbit with the orbits of the inner planets showing the points at which the debris from the comet intersect with the Earth’s orbit causing meteor showers. Diagram credit JPL Small-Body Database Browser with my annotations.
10/11/2019 – Ephemeris – Interstellar comet 2I/Borisov ejects the same gas like ordinary solar system comets
Ephemeris for Friday, October 11th. Today the Sun will be up for 11 hours and 12 minutes, setting at 7:05, and it will rise tomorrow at 7:54. The Moon, 2 days before full, will set at 6:24 tomorrow morning.
The interstellar comet 2I/Borisov, which was discovered August 30th by the Crimean amateur astronomer Gennady Borisov has given its first clues of its makeup. With data collected from the William Herschel Telescope in the Canary Islands the comet was discovered to give off cyanogen, a cyanide gas. This is just like what is given off by comets that belong to the solar system. As the comet comes closer to the Sun and warms up further more and different gasses will be liberated. It was the discovery of cyanogen in Halley’s Comet back in 1910 caused a panic because on that pass the comet’s tail swept past the Earth. However a comet’s tail is so tenuous that no cyanogen was detected in the Earth’s atmosphere.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Color photograph of 2I/Borisov. Image Credit: Gemini Observatory/NSF/AURA
Spectrum of 2I/Borisov. Top covers part of the visible and ultraviolet spectrum. The bottom zooms in on the CN emission. Credit https://arxiv.org/abs/1909.12144
10/09/2019 – Received word that C2 has also been discovered. This is also normal and can color the coma green. (I recorded the program on 10/06 illustrated this post on 10/07 due to being away due to my daughter’s surgery.)
05/05/2015 – Ephemeris – Eta Aquariids, an early visit of Halley’s Comet
Ephemeris for Tuesday, May 5th. Today the Sun will be up for 14 hours and 24 minutes, setting at 8:52. The Moon, 2 days past full, will rise at 10:29 this evening. Tomorrow the Sun will rise at 6:26.
The Eta Aquariid meteor shower will reach peak tomorrow morning. But the Moon will be bright, so only the brightest of them will be seen. However if you’re waiting to see the return of Halley’s Comet, you needn’t wait until the main body of the comet returns in 2061. Halley’s Comet has made many passes of the inner solar system in recorded history, and many more before that, returning to the inner solar system every 76 years or so, before returning to its frigid home beyond Neptune. It’s closest to the Sun, called perihelion is inside Venus’ orbit. On the way in and out it passes close to the Earth’s orbit. It has left a trail of debris, which we pass through in May and again in October.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Eta Aquariid radiant at 5 a.m. The radiant moves slowly to the east with time. Credit: My LookingUp program.
We get two meteor showers from Halley’s Comet. The Orionids, when Halley is approaching the inner solar system, and the Eta Aquariids when it’s leaving. Credit: My LookingUp program.
Bob Moler's Ephemeris Blog 