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Posts Tagged ‘summer solstice’

05/31/2016 – Ephemeris – Previewing June’s bright skies

May 31, 2016 Comments off

Ephemeris for Tuesday, May 31st.  Today the Sun will be up for 15 hours and 20 minutes, setting at 9:20, and it will rise tomorrow at 6:00.  The Moon, 2 days past last quarter, will rise at 3:55 tomorrow morning.

Tomorrow will be the first of June, so let’s preview June skies.  There will be a lot of sunlight in June.  The daylight hours will increase a bit from 15 hours and 21 minutes tomorrow to 15 hours and 34 minutes on the 20th, the solstice, retreating back to 15 hours 31 minutes at month’s end.  At this time of the year the sunset times for Ludington, Interlochen, Petoskey and Mackinaw City are very nearly the same.*  However the sunrise times are at their most divergent.  With Ludington’s sunrise being 14 minutes later than Mackinaw City’s.  The altitude of the sun above the southern horizon at local noon will increase from about 67 and a half degrees to 68 and three-quarters on the 20th.  Local noon, when the sun is actually due south will occur at about 1:43 p.m.

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

*  See http://ephemeris.bjmoler.org/calendar.htm

Addendum

June Star Chart

June star chart

Star Chart for June 2016. Created using my LookingUp program. To enlarge in Firefox Right-click on image then click View image.

The planets and stars are plotted for the 15th at 11 p.m. EDT.  That is chart time.  Note, Traverse City is located approximately 45 minutes behind our time meridian.  (An hour 45 minutes behind our daylight saving time meridian.) To duplicate the star positions on a planisphere you may have to set it to 1:45 earlier than the current time if you are near your time meridian.

Evening nautical twilight ends at 10:45 p.m. EDT on the 1st, increasing to 10:57 p.m. EDT on the 30th.

Morning nautical twilight starts at 4:36 a.m. EDT on the 1st, and decreasing to 4:35 a.m. EDT on the 30th.

Add a half hour to the chart time every week before the 15th and subtract a half hour for every week after the 15th.  Before the 13th also subtract an hour for Standard Time.

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
  • A leaky Big Dipper drips on Leo
  • Follow the arc of the handle of the Big Dipper to the star Arcturus
  • Extend the arc to a spike to point to Spica.
  • The Summer Triangle is outlined in red.  Vega in Lyra (Lyr), Deneb in Cygnus (Cyg) and Altair in Aquila (Aql).

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.  Some additions made to aid clarity.

    Date    Time      Event
Jun 01  We            Venus: 1.5° W
    03  Fr  1:43 a.m. Saturn Opposition
    03  Fr  5:47 a.m. Moon-Mercury: 0.7° N
    03  Fr  6:55 a.m. Moon Perigee: 361100 km
    04  Sa 11:00 p.m. New Moon
    05  Su  4:59 a.m. Mercury Greatest Elongation: 24.2° W
    06  Mo  5:13 a.m. Moon North Dec.: 18.6° N
    06  Mo  5:34 p.m. Venus Superior Conjunction with the Sun.
    10  Fr 10:47 a.m. Moon-Regulus: 2.2° N
    11  Sa  3:35 p.m. Moon-Jupiter: 1.6° N
    11  Sa  6:20 p.m. Moon Ascending Node
    12  Su  4:10 a.m. First Quarter
    13  Mo  6:06 a.m. Mercury-Pleiades: 6.8° S
    15  We  8:00 a.m. Moon Apogee: 405000 km
    18  Sa  8:40 p.m. Moon-Saturn: 3.6° S
    18  Sa 11:39 p.m. Mercury-Aldebaran: 3.8° N
    20  Mo  7:02 p.m. Full Moon
    20  Mo  2:52 p.m. Moon South Dec.: 18.6° S
    20  Mo  6:35 p.m. Summer Solstice
    26  Su  1:28 a.m. Moon Descending Node
    27  Mo  2:19 p.m. Last Quarter
Jul 01                Venus: 6.8° E

 

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06/19/2015 – Ephemeris – Two events this weekend: one local, one global

June 19, 2015 Comments off

Ephemeris for Friday, June 19th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31. The Moon, 3 days past new, will set at 11:34 this evening. Tomorrow the Sun will rise at 5:56.

There’s a couple of astronomical events coming up this weekend. On Saturday there will be another Sun ‘n Star Party at the Sleeping Bear Dunes National Lakeshore if weather cooperates. This time the telescopes will be set up at the Pierce Stocking Scenic Drive, Stop 3, the Dunes Overlook from 4 to 6 p.m. and from 9 to 11 p.m. The best place to park is Picnic Mountain, just before the Dunes Overlook. On Sunday a truly global event, the Summer solstice will occur at 12:38 p.m. (16:38 UT), when the Sun will reach its farthest north signaling the start of summer in the northern hemisphere. For folks south of the equator it will be the winter solstice signaling the start of winter for them.

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

Addendum

Summer Solstice Sun's Path

The Sun’s apparent path in the sky on the summer solstice. The cyan circle is the horizon and the Sun is plotted every 15 minutes throughout the day. Created by Bob Moler using LookingUp. This is a slide from his school program on the cause of the seasons.

06/01/2015 – Ephemeris – Starting orbit 41 looking at June skies

June 1, 2015 Comments off

Ephemeris for Monday, June 1st.  Today the Sun will be up for 15 hours and 20 minutes, setting at 9:21.   The Moon, 1 day before full, will set at 6:17 tomorrow morning and tomorrow the Sun will rise at 6:00.

We’ll start Ephemeris’ 41st orbit of the Sun by looking at the skies of June.  There’ will be a lot of sun in June and very little night.  The daylight hours will increase a bit from 15 hours and 20 minutes today to 15 hours and 34 minutes on the 21st, retreating back to 15 hours 31 minutes at month’s end.  At this time of the year the sunset times for Ludington, Interlochen, Petoskey and Mackinaw City are very nearly the same.  However the sunrise times are at their most divergent.  With Ludington’s sunrise being 14 minutes later than Mackinaw City’s.  The altitude of the sun above the southern horizon at local noon will hover around 68 to 69 degrees.  Local noon, when the sun is actually due south will occur at about 1:43 p.m.  Here’s what we’ve been waiting for:  Summer will start on the 21st at 12:38 p.m.

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

Addendum

June Star Chart

Star Chart for June 2015. Created using my LookingUp program.

The Moon is not plotted.

The planets and stars are plotted for the 15th at 11 p.m. EDT.  That is chart time.  Note, Traverse City is located 1 hour 45 minutes behind our time meridian.  To duplicate the star positions on a planisphere set it to 1 hour 45 minutes earlier than the current time.

Evening Astronomical twilight ends at 11:43 p.m. EDT on June 1st, increasing to midnight EDT on the 30th.

Morning astronomical twilight starts at 4:38 a.m. EDT on June 1st, and decreasing to 3:31 a.m. EDT on the 30th.

Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.

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

The green pointer from the Big Dipper is:

  • Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
  • Drill a hole in the bowl of the Big Dipper and the water will drip on the back of Leo the Lion.
  • Follow the arc of the Big Dipper’s handle to Arcturus
    • Continue with a spike to Spica
  • The Summer Triangle is shown in red

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 Daylight Time on a 24 hour clock.  Some additions made to aid clarity.

Conjunctions like the Moon-Saturn: 2.1° S means Saturn will appear 2.3° south of the Moon.

Jun 01 Mo Venus: 45.3° E
01 Mo 16:02 Moon-Saturn: 2° S
02 Tu 12:19 Full Moon
03 We 17:10 Moon South Dec.: 18.4° S
06 Sa 14:59 Venus Elongation: 45.4° E
09 Tu 11:42 Last Quarter
10 We 00:39 Moon Perigee: 369700 km
10 We 19:29 Moon Descending Node
13 Sa 04:59 Venus-Beehive: 0.6° N
14 Su 10:39 Mars Solar Conjunction
16 Tu 10:05 New Moon
16 Tu 15:47 Moon North Dec.: 18.5° N
20 Sa 07:28 Moon-Venus: 6.3° N
  21 Su 12:38 Summer Solstice
23 Tu 05:39 Mercury-Aldebaran: 1.9° N
23 Tu 13:01 Moon Apogee: 404100 km
24 We 07:03 First Quarter
24 We 12:59 Mercury Elongation: 22.5° W
24 We 13:23 Moon Ascending Node
28 Su 21:27 Moon-Saturn: 2.1° S
30 Tu 22:14 Venus-Jupiter: 0.3° N
Jul 01 We 02:48 Moon South Dec.: 18.4° S
01 We Venus: 42.4° E

06/20/2014 – Ephemeris – Summer is almost here!

June 20, 2014 1 comment

Ephemeris for Friday, June 20th.  Today the sun will be up for 15 hours and 33 minutes, setting at 9:31.   The moon, 1 day past last quarter, will rise at 2:21 tomorrow morning.  Tomorrow the sun will rise at 5:57.

Summer will begin at 6:52 tomorrow morning.  Great I can’t wait.  Summer is my favorite season, and it is especially welcome after the long and cold winter, and a not especially warm spring.  In the summer I move my operations to a table under a tree in the back yard, with a laptop and my radio tuned to IPR, of course.  There I conduct my research, take online teleconferences and courses and do my writing.  The summer solstice for us in the northern hemisphere is when the sun reaches its farthest north in the sky.  Around the Interlochen/Traverse City area that’s about 68.5 degrees above the southern horizon at solar noon, which is about 1:43 p.m. and staying up 15 hours and 33 minutes.

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

Addendum

Summer solstice

The earth centered on Michigan at 6:52 a.m. EDT, June 21, 2014 the moment of the summer solstice. Created using Celestia.

My summer office

My summer office

06/16/2014 – Ephemeris – Dates of the earliest sunrise and latest sunset

June 16, 2014 Comments off

Ephemeris for Monday, June 16th.  Today the sun will be up for 15 hours and 33 minutes, setting at 9:29.   The moon, half way from full to last quarter, will rise at 12:11 tomorrow morning.  Tomorrow the sun will rise at 5:56.

Yesterday saw the earliest sunrise for the year.  My sunrise times will start to show a change on Thursday.  The day-to-day change in sunrise times are now a few seconds.  The summer solstice, or longest day will be this Saturday, and the latest sunset won’t occur until next week Thursday.  The reason these dates don’t coincide has to do with the tilt of the earth’s axis and the earth’s slightly elliptical path around the sun.  Actually the disparity between these dates is more pronounced at the winter solstice when the Earth is closer to the sun and moving faster.  Yup, the sun is farther away now than it was in December.  Actually we’re moving slower now, so summer lasts a few days longer than winter.

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

 

02/18/2014 – Ephemeris – Gemini and the summer solstice

February 18, 2014 Comments off

Ephemeris for Tuesday, February 18th.  The sun will rise at 7:38.  It’ll be up for 10 hours and 37 minutes, setting at 6:15.   The moon, half way from full to last quarter, will rise at 10:19 this evening.

The constellation Gemini lies above and left of Orion in the southern evening sky.  Jupiter is now seen against its stars.  Gemini is called the twins and its head stars at the upper left of the constellation are Castor and Pollux.  Pollux is to the lower left of Castor.  Stick figures of the lads can be seen extending to the lower right of these stars.  Currently the place in the sky where the sun is on the winter solstice is just to the right of Castor’s big toe.  So it would seem that the sun is entering Gemini on the first day of summer, not Cancer as the astrologers would tell you.  That solstice point is moving westward at one degree every 71.6 years, a motion called precession.  I checked two astronomy programs and that point has now moved into Taurus the bull.

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

Addendum

Gemini and the summer solstice

The constellation Gemini and the summer solstice point in the sky. Created using Stellarium.

The summer solstice point in the sky is the intersection of the ecliptic, the suns path in the sky and the 6 hour line of right ascension which is like longitude on the earth.  The other blue lines are lines are lines of declination which is like latitude in the sky.  Note also that the summer solstice point is the point on the ecliptic closest to the blue declination line which is the 25º north declination line.  It’s at approximately 23½º north declination, right over the earth’s 23½º north latitude line also known as the Tropic of Cancer.

Back a couple of thousand of years ago the sun was entering the constellation of Cancer, off our image to the left, on the first day of summer.  Since then the summer solstice point has moved westward against the stars at one degree every 71.6 years.  This is due to what is called general precession, of the slow wobble of the earth’s axis caused by the  pull of the Moon and Sun on the Earth’s equatorial bulge.  This torques the earth and causes the 26,000 year wobble, like a spinning top.  Since back then the solstice point passed all the way across Gemini and in 1989 entered the territory of Taurus.

06/20/2013 – Ephemeris – Summer starts tomorrow

June 20, 2013 1 comment

Ephemeris for Thursday, June 20th.  Today the sun will be up for 15 hours and 33 minutes, setting at 9:31.   The moon, 3 days before full, will set at 4:15 tomorrow morning.  Tomorrow the sun will rise at 5:57.

Summer will arrive overnight at 1:04 a.m. tomorrow morning when the sun will reach its highest point in the northern sky.  If you were watching the sun’s shadow of a flag pole at local noon, when the sun is due south, it would be getting shorter every day since the winter solstice back on December 21st.  From tomorrow until the next winter solstice that shadow will be getting longer.  We are getting the most heat from the sun now due to the length of daylight and the high altitude of the sun most of the day. Because the earth and water takes time to heat up, we are not experiencing our greatest temperatures yet.  That will take a month or a month and a half.  That’s why solstice just starts summer and is not at the peak of it.

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

Addendum

Solstice shadows

Comparison of shadows between winter and summer solstices. Note the angles are approximate.