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10/19/2017 – Ephemeris – Bits of Halley’s Comet will rain down on Earth this weekend

October 19, 2017 1 comment

Ephemeris for Thursday, October 19th. The Sun will rise at 8:03. It’ll be up for 10 hours and 47 minutes, setting at 6:50. The Moon is new today, and won’t be visible.

The Orionid meteor shower is ramping up. This is the second of two visits of bits of Halley’s* comet this year, and every year, really. These are particles shed by the comet in past visits to the inner solar system. They are pretty much evenly strewn out along its orbit. The comet itself is now out past Neptune, and will reach aphelion, its farthest distance from the Sun around 2024, poised to head back to the inner solar system in 2061. It was last spotted in 2003 when it was just inside Neptune’s orbit. Anyway the Orionid meteors will appear to come from above the left side of constellation of Orion, about where the tip of his club is. They are best seen this weekend, in the early morning sky, with a possible 20 per hour visible.
Orionid meteor shower Saturday a.m.

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

* A contemporary of Edmund Halley, Samuel Pepys,  spelled his name Hawley.  We presume he pronounced it that way.

Addendum

Orionid radiant

The Orionid meteor shower radiant at 5 a.m. October 21, 2017. The radiant rises at 11 p.m., so the meteors will be visible from then into morning twilight. Dispite the lication of the radiant, the meteors will b e seen all over the sky.  However true Orionids can be traced back to the radiant point. Created using Stellarium.

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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).

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

July 27, 2017 1 comment

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

Two meteor showers

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.

05/01/2017 – Ephemeris – Previewing May 2017 Skies

May 1, 2017 Comments off

Ephemeris for Monday, May 1st.  The Sun rises at 6:32.  It’ll be up for 14 hours and 15 minutes, setting at 8:47.  The Moon, 1 day before first quarter, will set at 2:24 tomorrow morning.

Today starts the month of May when the promise of spring is finally fulfilled.  Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 15 minutes today to 15 hours 19 minutes on the 31st.  The altitude, or angle, of the Sun above the southern horizon at local noon will ascend from 61 degrees now to 67 degrees at month’s end.  The altitude of the sun in the Straits area will be a degree lower than that but your daylight hours will be a few minutes longer.  Local apparent noon this month, when the sun passes due south, will be about 1:38 p.m.

This is the month of the Eta Aquariid meteor shower which will reach its peak this Thursday and Friday.  There will be dark skies around 5 a.m. to see the meteors coming from the southeast.

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

Addenda

May Evening Star Chart

Star Chart for May 2017

Evening Star Chart for May 2017 (11 p.m. May 15, 2017). Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 11 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  11 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.

May Morning Star Chart

Star Chart for May 2017 mornings

Star Chart for May 2017 mornings based on 5 a.m. May 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
  • Follow the arc of the handle of the Big Dipper to the star Arcturus
  • The Summer Triangle is in red
  • The Eta Aquariid meteor shower radiant is in yellow and marked EAqR  is active from April 19th to May 28th and peaks May 6th.  Zenithal Hourly Rate at peak is expected to be 50, though considerably less than that is expected due to its radiant’s low position in our skies.  Data from the International Meteor Organization 2017 calendar.

Evening nautical twilight ends at 10:02 p.m. EDT on the 1st, increasing to 10:46 p.m. EDT on the 31st.
Evening astronomical twilight ends at 10:47 p.m. EDT on the 1st, increasing to 11:44 p.m. EDT on the 31st.
Morning astronomical twilight starts at 4:40 a.m. EDT on the 1st, and increasing to 3:44 a.m. EDT on the 31st.
Morning nautical twilight starts at 5:24 a.m. EDT on the 1st, and Increasing to 4:42 a.m. EDT on the 31st.

NASA Calendar of Planetary Events

Credit:  Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Time and follow the time change dates for Michigan, US

Date        Time    Event
May 01  Mo          Venus: 39.9° W
    02  Tu  2:23 pm Moon-Beehive: 3.7° N
    02  Tu 10:47 pm First Quarter
    04  Th  5:49 am Moon-Regulus: 0.6° N
    04  Th  6:42 am Moon Ascending Node
    04  Th 10:54 pm Eta Aquariid Shower: ZHR = 60
    05  Fr  9:51 am Mars-Aldebaran: 6.2° N
    07  Su  5:24 pm Moon-Jupiter: 2.3° S
    10  We  5:43 pm Full Moon
    12  Fr  3:51 pm Moon Apogee: 406200 km
    13  Sa  7:07 pm Moon-Saturn: 3.4° S
    14  Su  4:29 pm Moon South Dec.: 19.3° S
    17  We  6:59 pm Mercury Elongation: 25.8° W
    18  Th  8:33 pm Last Quarter
    18  Th  9:30 pm Moon Descending Node
    22  Mo  8:32 am Moon-Venus: 2.4° N
    23  Tu  9:20 pm Moon-Mercury: 1.6° N
    25  Th  3:44 pm New Moon
    25  Th  9:23 pm Moon Perigee: 357200 km
    27  Sa  7:36 pm Moon North Dec.: 19.4° N
    29  Mo  9:50 pm Moon-Beehive: 3.4° N
    31  We  7:56 am Moon Ascending Node
    31  We 12:08 pm Moon-Regulus: 0.3° N
Jun 01  Th          Venus: 45.8° W

May 2017 Calendar

LU                  Ephemeris of Sky Events for Interlochen/TC
May, 2017    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Mon  1| 06:32a  08:48p  14:15 | 10:00p  05:20a |      Set  02:24a   38%|
|Tue  2| 06:30a  08:49p  14:18 | 10:02p  05:18a |F Qtr Set  03:07a   49%|
|Wed  3| 06:29a  08:50p  14:21 | 10:03p  05:16a |      Set  03:43a   59%|
|Thu  4| 06:28a  08:51p  14:23 | 10:05p  05:15a |      Set  04:16a   70%|
|Fri  5| 06:26a  08:52p  14:26 | 10:06p  05:13a |      Set  04:45a   78%|
|Sat  6| 06:25a  08:54p  14:28 | 10:08p  05:11a |      Set  05:12a   86%|
+------+-----------------------+----------------+-----------------------+
|Sun  7| 06:24a  08:55p  14:31 | 10:09p  05:09a |      Set  05:39a   92%|
|Mon  8| 06:22a  08:56p  14:33 | 10:11p  05:08a |      Set  06:07a   97%|
|Tue  9| 06:21a  08:57p  14:36 | 10:13p  05:06a |      Set  06:36a   99%|
|Wed 10| 06:20a  08:58p  14:38 | 10:14p  05:04a |Full  Rise 08:45p  100%|
|Thu 11| 06:18a  09:00p  14:41 | 10:16p  05:03a |      Rise 09:42p   99%|
|Fri 12| 06:17a  09:01p  14:43 | 10:17p  05:01a |      Rise 10:38p   96%|
|Sat 13| 06:16a  09:02p  14:45 | 10:19p  05:00a |      Rise 11:30p   91%|
+------+-----------------------+----------------+-----------------------+
|Sun 14| 06:15a  09:03p  14:48 | 10:20p  04:58a |      Rise 12:19a   85%|
|Mon 15| 06:14a  09:04p  14:50 | 10:22p  04:57a |      Rise 01:03a   78%|
|Tue 16| 06:13a  09:05p  14:52 | 10:23p  04:55a |      Rise 01:44a   70%|
|Wed 17| 06:12a  09:06p  14:54 | 10:25p  04:54a |      Rise 02:21a   60%|
|Thu 18| 06:11a  09:08p  14:56 | 10:26p  04:52a |L Qtr Rise 02:54a   50%|
|Fri 19| 06:10a  09:09p  14:58 | 10:28p  04:51a |      Rise 03:26a   40%|
|Sat 20| 06:09a  09:10p  15:00 | 10:29p  04:50a |      Rise 03:57a   30%|
+------+-----------------------+----------------+-----------------------+
|Sun 21| 06:08a  09:11p  15:02 | 10:30p  04:48a |      Rise 04:28a   20%|
|Mon 22| 06:07a  09:12p  15:04 | 10:32p  04:47a |      Rise 05:02a   12%|
|Tue 23| 06:06a  09:13p  15:06 | 10:33p  04:46a |      Rise 05:38a    5%|
|Wed 24| 06:05a  09:14p  15:08 | 10:35p  04:45a |      Rise 06:20a    1%|
|Thu 25| 06:04a  09:15p  15:10 | 10:36p  04:44a |New   Set  09:04p    0%|
|Fri 26| 06:04a  09:16p  15:12 | 10:37p  04:42a |      Set  10:16p    2%|
|Sat 27| 06:03a  09:17p  15:13 | 10:39p  04:41a |      Set  11:21p    7%|
+------+-----------------------+----------------+-----------------------+
|Sun 28| 06:02a  09:18p  15:15 | 10:40p  04:40a |      Set  12:18a   15%|
|Mon 29| 06:02a  09:19p  15:17 | 10:41p  04:39a |      Set  01:05a   24%|
|Tue 30| 06:01a  09:19p  15:18 | 10:42p  04:38a |      Set  01:45a   34%|
|Wed 31| 06:00a  09:20p  15:19 | 10:43p  04:38a |      Set  02:19a   44%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

12/13/2016 – Ephemeris – The Geminid meteor shower will reach its peak tonight

December 13, 2016 Comments off

Ephemeris for Tuesday, December 13th.  The Sun will rise at 8:12.  It’ll be up for 8 hours and 50 minutes, setting at 5:02.  The Moon, at full today, will rise at 5:18 this evening.

The great meteor shower of December will reach its peak 7 p.m.  The shower is called the Geminids because they seem to come from the constellation of Gemini the twins. Unlike most meteor showers which have their highest numbers just before dawn, the normal highest numbers of meteors, when the radiant point is highest in the sky is between 2 and 3 a.m.  The radiant point, near the star Castor, the higher of the twin’s namesake stars will rise before 8 p.m. tonight.  In the last few years the Geminids have bested the Perseid shower of August for numbers of meteors.  The Geminids are caused by bits of rock that orbit the sun in a rather small but elongated orbit.  Unfortunately this year the Moon is full, so all but the brightest meteors will be drowned out by moonlight.

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

Addendum

Geminid Chart

The entire sky at the time the radiant (GemR) is at its highest. That’s actually 2:37 a.m. December 14th, 2016. The radiant’s altitude is 78º. Also shown is the Moon’s position. Created using my LookingUp program.  Click on the image to enlarge.

 

 

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.

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/