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08/10/2012 – Ephemeris – Weekend Meteor Watches
Ephemeris for Friday, August 10th. The sun rises at 6:39. It’ll be up for 14 hours and 15 minutes, setting at 8:54. The moon, 1 day past last quarter, will rise at 1:04 tomorrow morning.
There are two events this weekend to view the heavens and the Perseid meteor showers. First, part of the Port Oneida Fair the Grand Traverse Astronomical Society will work with the rangers of the Sleeping Bear Dunes National Lakeshore to hold a star party and meteor watch at Thoreson Farm on South Thoreson Road of M22, a couple miles north of Glen Arbor. That will start at 9 p.m. It will be about 10:30 when it’ll be dark enough spot the meteors. Sunday evening there’s a Meteors and S’mores event at the Leelanau State Park, at the tip of the Leelanau Peninsula. That event starts at 10:30 p.m. The society will participate there also. The moon won’t interfere with the meteor shower It’s been banished into the morning sky.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/09/2012 – Ephemeris – Viewing the Perseid meteor shower
Ephemeris for Thursday, August 9th. The sun rises at 6:38. It’ll be up for 14 hours and 17 minutes, setting at 8:56. The moon, at last quarter today, will rise at 12:24 tomorrow morning.
Lets take a look at what will happen this weekend with the Perseid meteor shower. We seem to have two meteoroid streams intercepting the earths. The earth will pass through the classic stream Saturday night, Sunday morning. The earth is expected to pass through a second stream Sunday Night, Monday morning. In the early evening the meteors are fewer, but the trails will be longer. The meteors will seem to come from the constellation of Perseus which lies below the W shaped constellation of Cassiopeia in the northeast. At two or three in the morning will see the greatest numbers of meteors, up to 60 meteors an hour. Tomorrow I’ll tell you about two events and places to go to join others in viewing the shower.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Perseid radiant at 10:30 p.m.
Perseid Meteor Shower radiant after midnight
08/07/2012 – Ephemeris – the comet responsible for the Perseid meteor shower
Ephemeris for Tuesday, August 7th. The sun rises at 6:36. It’ll be up for 14 hours and 22 minutes, setting at 8:59. The moon, 2 days before last quarter, will rise at 11:20 this evening.
The Perseid meteor shower is so named because the meteors seem to come from the direction of the constellation of Perseus which starts in the evening low in the northeast and rotates up throughout the night higher and higher. The comet responsible is Comet Swift-Tuttle, discovered in 1862 by Lewis Swift and Horace Tuttle. The comet has a 130 year orbit and returned in 1992. It’s orbit intersects ours at a 113 degree angle, which is why the radiant point is so far north. The Perseids have been recorded for 2,000 years so the comet has been around much longer than that. It’s nucleus is 17 miles in diameter, about twice that of Halley’s Comet. While Comet Swift-Tuttle won’t be back this century, we can see bits of it tonight.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/06/2012 – Ephemeris – The Perseid Meteor Shower this weekend
Aug 6. This is Bob Moler with Ephemeris for Monday, August 6th. The sun rises at 6:35. It’ll be up for 14 hours and 25 minutes, setting at 9:00. The moon, 3 days before last quarter, will rise at 10:52 this evening.
Saturday night through Sunday morning will be the period of the maximum number of meteors in the Perseid meteor shower. There are many meteor showers but a few very active ones. Of these the Perseids are the most famous. Meteor showers occur the same dates during the year because meteoroid streams are debris left near the orbits of comets. If a comet passes near the earth’s orbit the debris it sheds when close to the sun will end up in orbits similar to the comet and when the earth passes the spot we experience a meteor shower. Thus in late July through mid August we pass through the meteoroid stream of debris of Comet Swift-Tuttle, whose sand to pea sized particles hit the atmosphere at 40 miles per second providing us a celestial show.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
12/30/11 – Ephemeris – The best 2012 astronomical events
Friday, December 30th. The sun will rise at 8:19. It’ll be up for 8 hours and 51 minutes, setting at 5:10. The moon, 2 days before first quarter, will set at 12:02 tomorrow morning.
Let’s look ahead at next year’s astronomical events for this last Ephemeris of 2011. What won’t happen will be the end of the world on December 21st. There is no planet Nibiru. The closest alignment of the sun at the winter solstice and the center of the galaxy was in 1997. What will happen is partial eclipse of the sun, or about a half hour of it, before sunset on May 20th. An extremely rare transit of Venus, that is the planet Venus will cross the face of the sun on June 5th for us. We’ll see about 3 hours of it before sunset that day. The sun will continue to be more active next year with more sunspots and more displays of the northern lights. It will also be a good year for the Perseid meteor shower of August and the Geminids of December.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
08/11/11 – Ephemeris – Prospects for this year’s Perseid Meteor Shower
Thursday, August 11th. The sun rises at 6:40. It’ll be up for 14 hours and 14 minutes, setting at 8:54. The moon, 2 days before full, will set at 5:31 tomorrow morning.
In the next two nights the Perseid meteor shower will be at a peak. The problem this year will be that the moon is full, or full enough that the skies will not be dark all night. Hope is not completely lost, because there will be a few really bright meteors, a few an hour, rather than the 50 or more an hour visible in dark skies. The paths of meteors appear longer in the evening where the radiant point of the meteors lies low in the north northeast, when the bits of rock skip through our atmosphere at a very low angle. These bits of rock were liberated by comet Swift Tuttle on a prior pass of the inner solar system. It orbits the sun in 130 years, and its path takes it very close to the orbit of the earth, so this time of year we pass through its debris.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Perseid Meteor Shower radiant after midnight
The radiant is actually circumpolar for northern Michigan. At 10:30 p.m. it’s just east or the north compass point and very low on the horizon.
08/01/11 – Ephemeris – Previewing August skies
Monday, August 1st. The sun rises at 6:28. It’ll be up for 14 hours and 39 minutes, setting at 9:08. The moon, 2 days past new, will set at 9:52 this evening.
Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 39 minutes today to 13 hours 17 minutes on the 31st. The altitude of the sun at local noon, that is degrees of angle above the horizon will decrease from 63 degrees today to just over 53 degrees on the 31st. Straits area listeners can subtract one more degree from those angles. Local noon, when the sun is due south, is about 1:43 p.m. The Perseid meteor shower will reach its peak on the morning of the 12th, but will be mostly unseen due to the bright moon. However on the nights between now and then when the moon has set these meteors will still be plentiful. We saw two bright ones Saturday night at the Sleeping Bear Dunes viewing night.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/28/11 – Ephemeris – GTAS Night at the Lanphier Observatory
Thursday, July 28th. The sun rises at 6:24. It’ll be up for 14 hours and 48 minutes, setting at 9:12. The moon, 2 days before new, will rise at 5:08 tomorrow morning.
The Lanphier Observatory in Glen Arbor is open Wednesday and Thursday nights through August but only on clear evenings from 10 to midnight. The observatory is located close to the beach at the Leelanau School, just east of Glen Arbor on M22. I was asked by Norm Wheeler, who is the director of the observatory to help him out tonight, so I’m also inviting the crew over from the Grand Traverse Astronomical Society to help out with me. The Delta Aquarid meteor shower is reaching peak around now. These will seem to come from the southeast in the morning. Also beginning to show themselves in the Perseid meteor shower. The full moon will dim their maximum on August 12th, but early meteors can be seen from now until then when the moon isn’t up.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Bob Moler's Ephemeris Blog 