08/09/2021 – Ephemeris – The Perseid Meteors are coming!

This is Ephemeris for Monday, August 9th. Today the Sun will be up for 14 hours and 18 minutes, setting at 8:57, and it will rise tomorrow at 6:39. The Moon, 1 day past new, will set at 10:03 this evening.

If you’ve been out and about under the dark night skies in the last week or so, you may have spotted a few, what are sometimes called, falling or shooting stars. If these could be traced back to the northeastern sky, those were advance members of the Perseid Meteor Shower. The peak of the shower will be on the afternoon of Thursday the 12th, so actually the best time to see them will be in the early hours of that morning. With few exceptions, the best time to view meteors in general or a meteor shower is in the wee morning hours. The Perseids however favor us, because the point from which they seem to come, called the radiant, is so far north that it never sets for us, so they can be seen all night. In the evening, there are just fewer of them.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Perseid fireballs in one of NASA’s all sky cameras during the morning hours of August 13, 2017. This is a long time exposure. The bright swath in the image is the Moon that morning. Since it is a time exposure, the radiant is also moving with the earth’s rotation, so the meteors only seem to come from the northeastern sky. North is at the top, and East is to the left. Credit NASA.

08/11/2020 – Ephemeris – Tonight is the peak of the Perseid Meteor shower

This is Bob Moler with Ephemeris for Tuesday, August 11th. Today the Sun will be up for 14 hours and 12 minutes, setting at 8:53, and it will rise tomorrow at 6:42. The Moon, at last quarter today, will rise at 12:46 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 the next few mornings. In general Perseid meteors will be seen to come from the northeast. The evening view will be not hampered by the Moon until it rises at 12:46 am which will drown out the dimmer meteors. The best time to view is from about 10 or 10:30 pm to 12:46 am. The Perseids are the most active meteor shower visible in warm weather, with a possible over 50 meteors per hour.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

My best Perseid photo. From the 1970’s.

Perseid radiant at 11 pm, August 11th at the top of the constellation of Perseus, below the W shaped constellation of Cassiopeia. Click on the image to enlarge. Created using Stellarium.

07/29/2019 – Ephemeris – The South Delta Aquariid meteor shower is at peak now

Ephemeris for Monday, July 29th. Today the Sun will be up for 14 hours and 47 minutes, setting at 9:12, and it will rise tomorrow at 6:26. The Moon, 2 days before new, will rise at 4:30 tomorrow morning.

The South Delta Aquariid meteor shower is at its peak now. It’s not that great of a meteor shower. If its radiant were at the zenith we might expect 25 meteors an hour. The radiant will be highest low in the south at 3 a.m. However along with meteors appearing to radiate from the south from this meteor shower we expect growing numbers of meteors coming from the northeastern sky because the Perseid meteor shower that peaks around August 13th is beginning to be seen. The Perseids will be visible all night, but the South Delta Aquariids will be best seen after midnight. I suggest that you look for the Perseids before peak this year because the bright Moon will interfere at its peak.

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

Addendum

South Delta Aquariid meteor shower at peak and Perseids firing up at 3 a.m. July 30 2019. PerR and DAqrR are the radiants.

08/06/2018 – Ephemeris – The meteors of August, the Perseids are showing up now

Ephemeris for Monday, August 6th. The Sun rises at 6:34. It’ll be up for 14 hours and 27 minutes, setting at 9:01. The Moon, 2 days past last quarter, will rise at 2:27 tomorrow morning.

Over the past several weeks folks outdoors at night might have been seeing some shooting stars or meteors appearing to zip past in the sky. The ones I’m talking about seem to come from the northeast. These are the precursors of the Perseid meteor shower which will reach its peak on the night of August 12 and 13 this year. Over the millennia the meteoroid stream that feeds the meteors to our skies has spread out to last over a month from the latter half of July to three-quarters of August. We’ll meet the culprit for this show tomorrow. I try to use the proper terminology for all this. Meteoroid is the tiny body in space. In the Perseid’s case the size of a grain of sand to a pea. Meteor is the streak we see in the sky as it burns up.  Meteorite is the body that makes it to the ground.  To my knowledge no Perseid meteoroid has made it that far.

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

Addendum

The Perseid radiant at 11 p.m. tonight, August 6, 2018. Note that the radiant position is different from what I show on my charts for the month. The radiant there is for the night of the Maximum, August 12th. The radiant point shifts with time due to Earth’s changing position with the meteoroid stream. Click on image to enlarge. Created using Stellarium.

07/31/2018 – Ephemeris – Previewing August skies

Ephemeris for Tuesday, July 31st. The Sun rises at 6:27. It’ll be up for 14 hours and 41 minutes, setting at 9:09. The Moon, half way from full to last quarter, will rise at 11:17 this evening.

Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 39 minutes tomorrow 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 tomorrow 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 all night on the 12th. It will be a dark night with the one day old moon setting at 10 p.m. The radiant point, where the meteors will seem to come from, will be rising higher in the northeastern sky all night. On the 17th Venus will reach ts greatest separation from the Sun in the evening sky.

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

Addendum

August Evening Star Chart

Star Chart for August 2018 (10 p.m. EDT August 15, 2018). Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 10 p.m. EDT in the evening and 4:30 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian during EDT). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes earlier than the current time.

Note the chart times of 10 p.m. and 4:30 a.m. are for the 15th. For each week before the 15th add ½ hour (28 minutes if you’re picky). For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog.

August Morning Star Chart

Star Chart for August 2018 mornings based on 4:30 a.m. August 15th. Created using my LookingUp program. Click on image to enlarge.

For a list of constellation names to go with the abbreviations click here.

• Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
• Leaky Big Dipper drips on Leo.
• Follow the arc of the handle of the Big Dipper to the star Arcturus and
• Continue with a spike to Spica.
• The Summer Triangle is in red.
• PerR – Perseid meteor shower radiant

Twilight

	Morning	Twilight	Evening	Twilight	Dark	Night	Moon
Date	Astronomical	Nautical	Nautical	Astronomical	Start	End	Illum.
2018-07-31	4h28m	5h17m	22h28m	23h17m	23h17m	23h17m	0.89
2018-08-01	4h30m	5h18m	22h27m	23h15m	23h15m	23h43m	0.82
2018-08-02	4h32m	5h20m	22h25m	23h13m	23h13m	–	0.74
2018-08-03	4h34m	5h21m	22h24m	23h11m	23h11m	0h09m	0.64
2018-08-04	4h36m	5h23m	22h22m	23h09m	23h09m	0h37m	0.53
2018-08-05	4h38m	5h24m	22h20m	23h07m	23h07m	1h08m	0.42
2018-08-06	4h40m	5h26m	22h18m	23h05m	23h05m	1h44m	0.31
2018-08-07	4h42m	5h27m	22h17m	23h03m	23h03m	2h26m	0.20
2018-08-08	4h43m	5h29m	22h15m	23h00m	23h00m	3h18m	0.11
2018-08-09	4h45m	5h30m	22h13m	22h58m	22h58m	4h19m	0.05
2018-08-10	4h47m	5h32m	22h11m	22h56m	22h56m	4h47m	0.01
2018-08-11	4h49m	5h33m	22h10m	22h54m	22h54m	4h49m	0.00
2018-08-12	4h51m	5h35m	22h08m	22h52m	22h52m	4h51m	0.03
2018-08-13	4h53m	5h36m	22h06m	22h49m	22h49m	4h53m	0.08
2018-08-14	4h55m	5h38m	22h04m	22h47m	23h01m	4h55m	0.16
2018-08-15	4h56m	5h39m	22h02m	22h45m	23h29m	4h56m	0.26
2018-08-16	4h58m	5h41m	22h00m	22h43m	23h59m	4h58m	0.36
2018-08-17	5h00m	5h42m	21h58m	22h41m	–	5h00m	0.47
2018-08-18	5h02m	5h44m	21h56m	22h38m	0h30m	5h02m	0.57
2018-08-19	5h04m	5h45m	21h54m	22h36m	1h03m	5h04m	0.67
2018-08-20	5h05m	5h47m	21h53m	22h34m	1h40m	5h05m	0.76
2018-08-21	5h07m	5h48m	21h51m	22h32m	2h22m	5h07m	0.84
2018-08-22	5h09m	5h50m	21h49m	22h29m	3h09m	5h09m	0.90
2018-08-23	5h11m	5h51m	21h47m	22h27m	4h00m	5h11m	0.90
2018-08-24	5h12m	5h53m	21h45m	22h25m	4h56m	5h12m	0.95
2018-08-25	5h14m	5h54m	21h43m	22h23m	–	–	0.99
2018-08-26	5h16m	5h55m	21h41m	22h20m	–	–	1.00
2018-08-27	5h17m	5h57m	21h39m	22h18m	–	–	0.99
2018-08-28	5h19m	5h58m	21h37m	22h16m	–	–	0.97
2018-08-29	5h21m	6h00m	21h35m	22h14m	–	–	0.92
2018-08-30	5h22m	6h01m	21h33m	22h11m	22h11m	22h40m	0.86
2018-08-31	5h24m	6h02m	21h31m	22h09m	22h09m	23h09m	0.78

Twilight calendar was generated in Cartes du Ciel.

NASA Calendar of Planetary Events

Date        Time    Event
Aug 01  We          Venus: 45.1° E
    04  Sa  2:18 pm Last Quarter
    06  Mo  2:35 pm Moon-Aldebaran: 1.1° S
    08  We  6:33 pm Moon North Dec.: 20.8° N
    08  We  9:59 pm Mercury Inferior Conj.
    10  Fr  9:40 am Moon Ascending Node
    10  Fr  2:05 pm Moon Perigee: 358100 km
    11  Sa  5:47 am Partial Solar Eclipse (NE Canada to Asia)
    11  Sa  5:58 am New Moon
    12  Su  8:44 pm Perseid Meteor Shower: ZHR = 90
    14  Tu  9:35 am Moon-Venus: 6.4° S
    17  Fr  6:38 am Moon-Jupiter: 4.8° S
    17  Fr 11:59 am Venus Greatest Elongation: 45.9° E
    18  Sa  3:49 am First Quarter
    20  Mo 10:07 pm Mercury-Beehive: 5.9° S
    21  Tu  5:55 am Moon-Saturn: 2.4° S
    21  Tu 10:58 pm Moon South Dec.: 20.8° S
    23  Th  7:23 am Moon Apogee: 405700 km
    24  Fr 12:51 am Moon Descending Node
    26  Su  7:56 am Full Moon
    26  Su  3:59 pm Mercury Greatest Elongation: 18.3° W
Sep 01  Sa          Venus: 45° E

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html

If you go to the above site you can print out a list like the above for the entire year
or calendar pages for your time zone.

Sun and Moon Rising and Setting Events

     LU              Ephemeris of Sky Events for Interlochen/TC
     August, 2018    Local time zone: EDT
     +-----------------------------------------------------------------------+
     | DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
     |      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
     +=======================================================================+
     |Wed  1| 06:29a  09:08p  14:39 | 10:23p  05:13a |      Rise 11:43p   77%|
     |Thu  2| 06:30a  09:07p  14:37 | 10:22p  05:14a |      Rise 12:09a   68%|
     |Fri  3| 06:31a  09:05p  14:34 | 10:20p  05:16a |      Rise 12:37a   58%|
     |Sat  4| 06:32a  09:04p  14:32 | 10:18p  05:17a |L Qtr Rise 01:08a   47%|
     +------+-----------------------+----------------+-----------------------+
     |Sun  5| 06:33a  09:03p  14:29 | 10:17p  05:19a |      Rise 01:44a   37%|
     |Mon  6| 06:34a  09:01p  14:27 | 10:15p  05:20a |      Rise 02:27a   26%|
     |Tue  7| 06:35a  09:00p  14:24 | 10:13p  05:22a |      Rise 03:18a   17%|
     |Wed  8| 06:37a  08:59p  14:22 | 10:11p  05:23a |      Rise 04:20a    9%|
     |Thu  9| 06:38a  08:57p  14:19 | 10:10p  05:25a |      Rise 05:30a    3%|
     |Fri 10| 06:39a  08:56p  14:16 | 10:08p  05:26a |      Rise 06:45a    0%|
     |Sat 11| 06:40a  08:54p  14:14 | 10:06p  05:28a |New   Set  09:21p    1%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 12| 06:41a  08:53p  14:11 | 10:04p  05:29a |      Set  09:58p    4%|
     |Mon 13| 06:42a  08:51p  14:08 | 10:02p  05:31a |      Set  10:30p   10%|
     |Tue 14| 06:44a  08:50p  14:06 | 10:00p  05:32a |      Set  11:00p   17%|
     |Wed 15| 06:45a  08:48p  14:03 | 09:59p  05:34a |      Set  11:29p   27%|
     |Thu 16| 06:46a  08:46p  14:00 | 09:57p  05:35a |      Set  11:59p   36%|
     |Fri 17| 06:47a  08:45p  13:57 | 09:55p  05:37a |      Set  12:29a   47%|
     |Sat 18| 06:48a  08:43p  13:54 | 09:53p  05:38a |F Qtr Set  01:03a   57%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 19| 06:49a  08:42p  13:52 | 09:51p  05:40a |      Set  01:40a   66%|
     |Mon 20| 06:51a  08:40p  13:49 | 09:49p  05:41a |      Set  02:22a   75%|
     |Tue 21| 06:52a  08:38p  13:46 | 09:47p  05:43a |      Set  03:09a   83%|
     |Wed 22| 06:53a  08:37p  13:43 | 09:45p  05:44a |      Set  04:00a   89%|
     |Thu 23| 06:54a  08:35p  13:40 | 09:43p  05:46a |      Set  04:56a   94%|
     |Fri 24| 06:55a  08:33p  13:37 | 09:41p  05:47a |      Set  05:54a   98%|
     |Sat 25| 06:56a  08:31p  13:34 | 09:39p  05:48a |      Set  06:54a  100%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 26| 06:58a  08:30p  13:31 | 09:37p  05:50a |Full  Rise 08:54p  100%|
     |Mon 27| 06:59a  08:28p  13:29 | 09:35p  05:51a |      Rise 09:21p   98%|
     |Tue 28| 07:00a  08:26p  13:26 | 09:33p  05:53a |      Rise 09:47p   94%|
     |Wed 29| 07:01a  08:24p  13:23 | 09:31p  05:54a |      Rise 10:13p   88%|
     |Thu 30| 07:02a  08:23p  13:20 | 09:29p  05:56a |      Rise 10:40p   81%|
     |Fri 31| 07:04a  08:21p  13:17 | 09:27p  05:57a |      Rise 11:09p   72%|
     +-----------------------------------------------------------------------+
     * Nautical Twilight
     ** Moon rise or moon set, whichever occurs between sunrise and sunset

Ephemeris of Sky Events is created with my DOS version LookingUp program.

07/27/2017 – Ephemeris – Two meteor showers, one peaking another ramping up

Ephemeris for Thursday, July 27th. The Sun rises at 6:23. It’ll be up for 14 hours and 49 minutes, setting at 9:13. The Moon, 3 days before first quarter, will set at 11:50 this evening.

We are in the season for meteor showers. Today the South Delta Aquariid Meteor Shower will reach peak. This is a not very active shower where the meteors will seem to come from low in the southeastern sky after midnight. The radiant will rotate to the south by 5 a.m. The moon won’t bother it for the next few days. The number of meteors seen will be under 20 per hour. This long-lasting shower will still add a few meteors when the famous Perseid meteor shower begin to appear, which is around now. These meteors will seem to come from the northeastern part of the sky, and will reach peak for us in the evening hours of August 12th. On that night the Moon will brighten the sky after 11:30 p.m. So for the next two weeks both shower meteors can be seen.

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

Addendum

The sky at 1 a.m. tomorrow morning, July 28, 2017 showing the South Delta Aquariid (DAqR) and Perseid (PerR) meteor radiants. Created using my LookingUp program.

08/03/2015 – Ephemeris – The Perseids are coming!

Ephemeris for Monday, August 3rd.  The Sun rises at 6:30.  It’ll be up for 14 hours and 35 minutes, setting at 9:06.   The Moon, half way from full to last quarter, will rise at 10:58 this evening.

After the Moon sets in the evening and morning hours for the next week and a half the numbers of meteors visible will increase each night.  These are members of the Perseid meteor shower of August.  The peak this year is expected to be during the 2 o’clock hour on the morning of the 13th.  These meteors are the result of debris left in the orbit of Comet Swift-Tuttle shed by innumerable visits to the inner solar system.  Every year at this time the Earth passes through this trail of debris which intersects its orbit giving rise to the meteor shower.  We call them the Perseids, because the appear to come from the direction of the constellation Perseus the hero, which is first seen in the early evening low in the northeast.

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.

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)

The distances in the lower left corner are the comet’s current distances from the Earth and Sun.  AU is astronomical units the mean distance between the Earth and Sun.  The comet’s last pass through the inner solar system was in 1992.  Swift-Tuttle is now out just past the current position of the dwarf planet Pluto.  Link to the animation from which the above image was taken and other information on Comet Swift-Tuttle go to http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=109P;cad=1