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Posts Tagged ‘Perseid meteor shower’

08/08/2017 – Ephemeris – The Harvest Moon effect starts showing up 2 months early

August 8, 2017 1 comment

Ephemeris for Tuesday, August 8th. The Sun rises at 6:37. It’ll be up for 14 hours and 20 minutes, setting at 8:58. The Moon, 1 day past full, will rise at 9:34 this evening.

The Harvest moon is nearly 2 months away, but some of its effects are starting to be felt now. I call it the Harvest Moon Effect. The Harvest Moon is a bit late this year, October 5th. It’s defined as the nearest full moon to the autumnal equinox. However from August to October the rising times of the full Moon and nights after for the next week don’t advance very fast. On average the Moon rises 50 minutes later each night. Between tonight and tomorrow night the interval will be 32 minutes. This is kind of a bummer this weekend when the Perseid meteor shower reaches peak. As with most meteor showers, the most meteors seen are after midnight. Saturday night’s Perseid peak has the Moon, six days after full rising at 11:36 p.m.

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

Addendum

Moonrise time intervals for the rest of this week:

Date Moonrise Difference
08/08/17 9:34 p.m.
32 minutes
08/09/17 10:06 p.m.
30 minutes
08/10/17 10:36 p.m.
30 minutes
08/11/17 11:06 p.m.
30 minutes
08/12/17 11:36 p.m.
Harvest Moon Effect

Harvest Moon Effect for this week. Note how shallow the path of the Moon is in relation to the eastern horizon. I’ve made the earth transparent so we can see the Moon below the horizon. As the Earth rotates the Moon will rise in a direction parallel to the celestial equator. In contrast the Moon’s path around March is steeper than average, so the interval in consecutive lunar rise times is much longer than the 50 minute average. Created using Cartes du Ciel (Sky Charts).

08/01/2017 – Ephemeris – A look at the busy month of August in astronomy

August 1, 2017 1 comment

Ephemeris for Tuesday, August 1st. The Sun rises at 6:29. It’ll be up for 14 hours and 38 minutes, setting at 9:07. The Moon, 2 days past first quarter, will set at 2:21 tomorrow morning.

Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 38 minutes today to 13 hours 16 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. The Perseid meteor shower will reach its peak on the evening of the 12th. However the bright waning gibbous moon will rise just after 11:30 for a very short dark sky viewing period. The big event this month will be the total solar eclipse that will be visible from all 50 of the United States and total for a narrow strip of land stretching from Oregon to South Carolina. That will occur on the afternoon of Monday the 21st.

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

Addenda

August Evening Star Chart

August Star Chart

Star Chart for August 2017 (10 p.m. August 15, 2017). 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 5 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 and 45 minutes behind our daylight standard time meridian. during EST). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes (Daylight Time) or 45 minutes (Standard Time) earlier than the current time if you are near your time meridian.

Note the chart times of 10 p.m. and 5 a.m. are for the 15th. For each week before the 15th add ½ hour. For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog.

August Morning Star Chart

Morning Star Chart

Star Chart for August 2017 mornings based on 5 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,
  • Then follow the Spike to Spica
  • The Summer Triangle is in red
  • PerR is the Perseid Meteor Shower radiant

Evening nautical twilight ends at 10:26 p.m. EDT on the 1st, decreasing to 9:30 p.m. EDT on the 31st.
Evening astronomical twilight ends at 11:15 p.m. EDT on the 1st, decreasing to 10:09 p.m. EDT on the 31st.
Morning astronomical twilight starts at 4:30 a.m. EDT on the 1st, and increasing to 5:24 a.m. EDT on the 31st.
Morning nautical twilight starts at 5:19 a.m. EDT on the 1st, and increasing to 6:03 a.m. EDT on the 31st.

NASA Calendar of Planetary Events

Date        Time    Event
Aug 01  Tu          Venus: 38.4° W
    02  We  1:55 pm Moon Apogee: 405000 km
    03  Th  3:31 am Moon-Saturn: 3.8° S
    04  Fr  2:17 pm Moon South Dec.: 19.4° S
    07  Mo  2:11 pm Full Moon
    07  Mo  2:22 pm Partial Lunar Eclipse (Not visible from here)
    08  Tu  6:56 am Moon Descending Node
    12  Sa  2:35 pm Perseid Shower: ZHR = 90
    14  Mo  9:15 pm Last Quarter
    16  We  2:39 am Moon-Aldebaran: 0.4° S
    18  Fr  2:50 am Moon North Dec.: 19.4° N
    18  Fr  9:14 am Moon Perigee: 366100 km
    19  Sa 12:45 am Moon-Venus: 2.3° N
    20  Su  3:15 am Moon-Beehive: 3.2° N
    21  Mo  6:34 am Moon Ascending Node
    21  Mo  2:26 pm Total Solar Eclipse
    21  Mo  2:30 pm New Moon
    25  Fr  9:00 am Moon-Jupiter: 3.7° S
    26  Sa  4:32 pm Mercury Inferior Conj.
    29  Tu  4:13 am First Quarter
    30  We  7:25 am Moon Apogee: 404300 km
    30  We 10:23 am Moon-Saturn: 3.9° S
    31  Th 10:03 pm Moon South Dec.: 19.4° S
Sep 01  Fr          Venus: 31.7° W

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.

August Rising and Setting Events

LU                  Ephemeris of Sky Events for Interlochen/TC
August, 2017    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Tue  1| 06:29a  09:08p  14:38 | 10:23p  05:13a |      Set  02:21a   72%|
|Wed  2| 06:30a  09:06p  14:36 | 10:21p  05:15a |      Set  03:00a   80%|
|Thu  3| 06:31a  09:05p  14:34 | 10:20p  05:16a |      Set  03:43a   87%|
|Fri  4| 06:32a  09:04p  14:31 | 10:18p  05:18a |      Set  04:32a   93%|
|Sat  5| 06:33a  09:02p  14:29 | 10:16p  05:19a |      Set  05:26a   97%|
+------+-----------------------+----------------+-----------------------+
|Sun  6| 06:34a  09:01p  14:26 | 10:15p  05:21a |      Set  06:24a   99%|
|Mon  7| 06:36a  09:00p  14:23 | 10:13p  05:22a |Full  Rise 09:01p  100%|
|Tue  8| 06:37a  08:58p  14:21 | 10:11p  05:24a |      Rise 09:35p   98%|
|Wed  9| 06:38a  08:57p  14:18 | 10:09p  05:25a |      Rise 10:06p   95%|
|Thu 10| 06:39a  08:55p  14:16 | 10:07p  05:27a |      Rise 10:36p   89%|
|Fri 11| 06:40a  08:54p  14:13 | 10:06p  05:28a |      Rise 11:06p   81%|
|Sat 12| 06:41a  08:52p  14:10 | 10:04p  05:30a |      Rise 11:36p   72%|
+------+-----------------------+----------------+-----------------------+
|Sun 13| 06:43a  08:51p  14:08 | 10:02p  05:31a |      Rise 12:09a   62%|
|Mon 14| 06:44a  08:49p  14:05 | 10:00p  05:33a |L Qtr Rise 12:46a   51%|
|Tue 15| 06:45a  08:48p  14:02 | 09:58p  05:34a |      Rise 01:28a   39%|
|Wed 16| 06:46a  08:46p  13:59 | 09:56p  05:36a |      Rise 02:16a   28%|
|Thu 17| 06:47a  08:44p  13:57 | 09:54p  05:37a |      Rise 03:13a   18%|
|Fri 18| 06:49a  08:43p  13:54 | 09:52p  05:39a |      Rise 04:16a   10%|
|Sat 19| 06:50a  08:41p  13:51 | 09:50p  05:40a |      Rise 05:24a    4%|
+------+-----------------------+----------------+-----------------------+
|Sun 20| 06:51a  08:39p  13:48 | 09:48p  05:42a |      Rise 06:35a    1%|
|Mon 21| 06:52a  08:38p  13:45 | 09:47p  05:43a |New   Set  08:44p    0%|
|Tue 22| 06:53a  08:36p  13:42 | 09:45p  05:44a |      Set  09:18p    2%|
|Wed 23| 06:54a  08:34p  13:39 | 09:43p  05:46a |      Set  09:49p    6%|
|Thu 24| 06:56a  08:33p  13:37 | 09:41p  05:47a |      Set  10:18p   12%|
|Fri 25| 06:57a  08:31p  13:34 | 09:39p  05:49a |      Set  10:46p   20%|
|Sat 26| 06:58a  08:29p  13:31 | 09:37p  05:50a |      Set  11:15p   28%|
+------+-----------------------+----------------+-----------------------+
|Sun 27| 06:59a  08:27p  13:28 | 09:35p  05:52a |      Set  11:46p   37%|
|Mon 28| 07:00a  08:26p  13:25 | 09:33p  05:53a |      Set  12:19a   47%|
|Tue 29| 07:01a  08:24p  13:22 | 09:31p  05:54a |F Qtr Set  12:56a   56%|
|Wed 30| 07:03a  08:22p  13:19 | 09:29p  05:56a |      Set  01:38a   65%|
|Thu 31| 07:04a  08:20p  13:16 | 09:27p  05:57a |      Set  02:24a   74%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

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.

08/10/2016 – Ephemeris – The planets tonight

August 10, 2016 Comments off

Ephemeris for Wednesday, August 10th.  The Sun rises at 6:39.  It’ll be up for 14 hours and 15 minutes, setting at 8:55.  The Moon, at first quarter today, will set at 12:55 tomorrow morning.

Today we turn from the small meteoroids that orbit the Sun that are producing the Perseid Meteor Shower to the larger members of the solar family, namely the bright planets. Venus and Mercury are very low in the west-northwest and will set at 9:44 and 9:50 p.m. respectively.  Jupiter is in the west in the evening.  It will set at 10:19 p.m.  Mars, Saturn and the star Antares start the evening in the south-southwestern sky as a tightening triangle, moving to the southwest during the evening.  Antares, whose name means Rival of Mars is below Saturn with brighter Mars to the right.  The Red Planet is back in Scorpius.  It will set at 12:46 a.m.  Mars is moving rapidly to the east against the stars.  Saturn is spectacular in telescopes, with its rings.  Saturn will set at 1:34 a.m.

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

Addendum

Sunset planets

Venus, Mercury and Jupiter at 9:25 p.m. (30 minutes after sunset), August 10, 2016. Created using Stellarium.

Evening planets and the Moon

The planets, Moon and constellations at 10 p.m., August 10, 2016. Created using Stellarium.

Binocular Moon

The Moon as it might appear in binoculars tonight, August 10, 2016 at 10 p.m. Created using Stellarium.

Saturn and its moons

Saturn and its moons at 10 p.m. August 10, 2016. Created using Cartes du Ciel (Sky Charts).

The planets and the Moon all night

Planets at sunset and sunrise of a single night starting with sunset on the right on August 10, 2016. The night ends on the left with sunrise on August 11. Actually all the naked eye planets are in the evening sky. Also shown is the Perseid meteor shower radiant. If you are using Firefox right-click on the image and select View Image to enlarge the image. That goes for all the large images. Created using my LookingUp program.

Also shown is the Perseid meteor shower radiant.

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/