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11/17/2016 – Ephemeris – The Leonid meteor shower will be hampered by the Moon tomorrow morning

November 17, 2016 Comments off

Ephemeris for Thursday, November 17th.  The Sun will rise at 7:43.  It’ll be up for 9 hours and 29 minutes, setting at 5:12.  The Moon, 3 days past full, will rise at 8:39 this evening.

The Leonid meteor shower, which reaches peak activity today is going to be washed out by the bright Moon.  The International Meteor Organization doesn’t have anything specific on it this year.  On most years, it produces only 15 meteors an hour tops.  However about every 33 years or so all heaven breaks loose.  From the predictions I’ve seen the fun starts in 2034 and lasts a few years.  The reason for the spectacular meteor storms, as they call them, is that the responsible comet, 55P Tempel-Tuttle, has a debris clump that hasn’t fanned out much along its orbit, so we get intense meteor activity when the comet again enters the inner solar system.  It’s expected back in 2031 with its main cloud of meteoroids a couple of years later.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Leonid Radiant

Leonid meteor radiant at about 2 a.m. from Traverse City.  Credit:  My LookingUp program.

1833 meteor storm

A famous woodcut of the 1833 Leonid meteor storm.

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11/11/2016 – Ephemeris – Two Taurid meteor showers active now

November 11, 2016 Comments off

Ephemeris for Veteran’s Day, Friday, November 11th.  The Sun will rise at 7:35.  It’ll be up for 9 hours and 43 minutes, setting at 5:18.  The Moon, 3 days before full, will set at 4:49 tomorrow morning.

We are situated between two supposed peaks of two meteor showers, the South Taurids and the Northern Taurids.  Their radiant points are roughly north and south of the face of Taurus the bull, which looks like the letter V of stars lying on its side.  Both meteoroid streams belong to Encke’s Comet, the comet with the shortest known period of 3.3 years.  The far end of the streams end up near Jupiter’s orbit, which allow the giant planet to split and broaden the meteoroid streams.  Another feature of these streams is that they seem to be made of small pebbles rather than grains.  When these pebbles hit our atmosphere at 17 miles (28 km) per second they will appear very bright.  Really bright meteors are called Fireballs.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Fireball orbits or November 9th, 2016

Fireball orbits traced back from November 9, 2016. The orbits marked in yellow sticking out o the right toward Jupiter’s orbit are the Taurids. Credit NASA All-sky Fireball Network via spaceweather.com.

NASA has three widely spaced sets of all-sky cameras which allow it to get 3-D views of fireballs entering the Earth’s atmosphere.  which allow the measurement of velocity of the object and the determination of the meteoroid’s orbit before it hit Earth’s atmosphere.  For more information go to:  http://fireballs.ndc.nasa.gov/

 

08/11/2016 – Ephemeris – The Perseid meteors will peak tonight!

August 11, 2016 Comments off

Ephemeris for Thursday, August 11th.  The Sun rises at 6:41.  It’ll be up for 14 hours and 12 minutes, setting at 8:53.  The Moon, 1 day past first quarter, will set at 1:31 tomorrow morning.

This evening and tomorrow morning we should see the peak of the Perseid Meteor Shower.  There is the expected broad peak of the shower which for us is after sunrise.  However the meteoroid stream isn’t monolithic.  Each pass of the comet in the inner solar system superimposes its debris on the general stream, so we will have increased activity all night tonight and even into Saturday morning.  In general Perseid meteors will be seen to come from the northeast.  The evening view will be hampered by the Moon which will drown out the dimmer meteors.  The best time to view is after the Moon sets at 1:31 tomorrow morning until morning twilight becomes noticeable around 5 a.m. when over 100 meteors might be spotted an hour.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Perceid Radiant

The Perseid meteor shower radiant a about 2 a,m, during the period of the shower. Created using my LookingUp program.

Perseid Meteors

Here are some meteors seen in the 2007 Perseid meteor shower taken by Scott Anttila. The image is centered on Cassiopeia. The radiant is low and a bit left of center in the image. The Double Cluster is seen below center and the Great Andromeda Galaxy is seen on the right just above center.

My best Perseid photo. From the 70's.

My best Perseid photo. From the 70’s.

08/09/2016 – Ephemeris – A look at the Perseids progenitor

August 9, 2016 Comments off

Ephemeris for Tuesday, August 9th.  The Sun rises at 6:38.  It’ll be up for 14 hours and 18 minutes, setting at 8:56.  The Moon, 1 day before first quarter, will set at 12:23 tomorrow morning.

Comet Swift-Tuttle is the comet responsible for the Perseid Meteor Shower which is now ramping up and will reach its peak Thursday night and Friday morning.  The comet was independently discovered by Swift and Tuttle in the summer of 1862.  Based on three months of observations it was predicted to return after 120 years in 1982. After it failed to appear more work was done to refine the orbit, and to check for past appearances of the comet.  Sure enough comets appearing to fit the orbit were found in 188 CE and 69 BCE, so a new prediction for the comet to reappear was made for 1992 by the late Dr. Brian Marsden of the Smithsonian Astrophysical Observatory.  His revised prediction was only off by 17 days.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Orbit of Comet Swift-Tuttle

Orbit of Comet 109P/Swift-Tuttle. Blue line is the comet’s orbit, coming from above (North). Credit NASA / JPL / Applet by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).

 

Comet Swift-Tuttle orbit

Orbit of Comet 109P/Swift-Tuttle. Blue line is the comet’s orbit, coming from above. That’s why the radiant is so far north.  See yesterday’s post for the radiant point. Credit NASA / JPL / Applet by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).

These were generated a couple of years ago.  However the comet won’t be back until 2122 give or take.

08/08/2016 – Ephemeris – This week the Perseid meteors ramp up

August 8, 2016 Comments off

Ephemeris for Monday, August 8th.  The Sun rises at 6:37.  It’ll be up for 14 hours and 20 minutes, setting at 8:58.  The Moon, 2 days before first quarter, will set at 11:54 this evening.

The Perseid meteor shower will reach its peak for this year between 9 and 11:30 a.m. Friday morning, the 12th.   There is some expectation that there will be an enhancement of meteor numbers on Thursday evening before midnight.  Our problem is that the Moon will be out and bright Thursday evening and will set at 1:31 a.m. Friday morning.  The bright Moon doesn’t preclude seeing meteors, but only the brightest ones will be visible.  Also we have been seeing precursor meteors for the last three weeks, slowly ramping up to Friday morning’s peak.  You’ll see them every night this week.  The meteors are caused by the debris from Comet Swift-Tuttle whose 130 year orbit of the Sun over the millennia, has strewn meteoroids along its orbit.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The Perseid meteor shower radiant is circumpolar for northern Michigan, so the meteors will be visible all night.

Perseid radiant at 10:30 p.m.

Perseid radiant at 10:30 p.m.

Perseid Meteor Shower radiant after midnight

Perseid Meteor Shower radiant after midnight

07/28/2016 – Ephemeris – Two upcoming meteor showers plus an occultation tomorrow morning

July 28, 2016 Comments off

Ephemeris for Thursday, July 28th.  The Sun rises at 6:25.  It’ll be up for 14 hours and 47 minutes, setting at 9:12.  The Moon, 2 days past last quarter, will rise at 2:31 tomorrow morning.

We have a couple of meteor showers of note coming up.  The first is the Southern Delta Aquariids which will peak on the 30th.  The radiant point for these meteors will rise around midnight in the southeast.  Their numbers and their brightness are not very great.  The Perseid meteor shower peak will have interference from the waxing gibbous moon drowning out all but the brightest meteors on the evening of August 11 and morning of he 12th.  However the Perseids have a long run up to their peak, so their numbers will grow after the moon sets.  The Perseid radiant is circumpolar for Northern Michigan, meaning it never sets, so some Perseid meteors can always be seen at night.  Their radiant will be low in the northeastern sky in the evening and much higher in the northeast just before dawn.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addenda

South Delta Aquarids

Approximate Radiant of the South Delta Aquariid meteor shower. The radiant does move over the several weeks of the shower to the east. Created using my LookingUp program.

Perseid Meteor Shower radiant after midnight

Perseid Meteor Shower radiant after midnight. Created using my LookingUp program.

Update: Occultation of Aldebaran tomorrow morning

Aldebaran Occultation

The area where the occultation of Aldebaran will be visible. The area bordered by the white lines is where the occultation will occur with the Sun below the horizon. Credit IOTA’s Occult 4 program.

There will be an occultation of Aldebaran by the Moon centered on 11:16 UT (7:16 a.m. EDT) July 29, 2016.  Our area (Michigan) cannot see the event, being too far north.  It will be visible south of a line containing the state of Maine down through Texas.  Universe Today has information on grazing occultation possibilities: http://www.universetoday.com/129841/spectacular-aldebaran-graze-july-29/

 

12/14/2015 – Ephemeris – The Geminids reach peak today – See ’em morning or evening

December 14, 2015 Comments off

Ephemeris for Monday, December 14th.  The Sun will rise at 8:12.  It’ll be up for 8 hours and 50 minutes, setting at 5:02.   The Moon, 3 days past new, will set at 8:42 this evening.

The Geminid meteor shower is ongoing right now.  The peak is expected to be near 1 p.m. today.  So the numbers seen this morning while it’s still dark should be about the same as will be seen this evening.  Not peak numbers, but it should be a good show nonetheless if it’s clear tonight.  The radiant is in the constellation of Gemini above Orion.  The source of this shower is an asteroid rather than a comet.  It may be a burnt out comet which lost all its frozen gasses.  It has a definite highly elliptical orbit of a comet and comes very close to the Sun, where one of the STEREO Sun monitoring spacecraft saw it ejecting a cloud of dust.  It may be classed as a rock comet for that reason, blurring the line between comets and asteroids.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

All sky

All Sky view one hour intervals for The Geminid meteor shower the night of December 13-14, 2015.. Note the radiant “GemR”. Created with my LookingUp program and GIMP.

Geminid

A Geminid and the aurora borealis from Norway. Found this in a NASA blog (link below) uncredited). However I was able to find the credit: Image Credit & Copyright: Bjørnar G. Hansen.

The image above was also an Astronomy Picture of the Day.  Here’s a link to the NASA blog dated December 9, 2015 about live tweeting the Geminids.