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09/28/2015 – Ephemeris – The Harvest Moon effect

September 28, 2015 Comments off

Ephemeris for Monday, September 28th.  The Sun will rise at 7:36.  It’ll be up for 11 hours and 52 minutes, setting at 7:29.   The Moon, 1 day past full, will rise at 8:00 this evening.

Yesterday’s full moon was the famous Harvest Moon, the nearest full moon to the autumnal equinox.  This is a time of the full and waning gibbous moons in the next few days rising in twilight.  In the old days before electric lights it helped farmers by effectively lengthening the hours of light to gather in the crops.  The Moon on average rises 50 minutes later each night.  The interval between tonight’s moon rise and tomorrow’s will be 38 minutes.  The interval between Tuesday and Wednesday will be 42 minutes.  This year’s harvest moon effect is spoiled a bit because the Moon was at perigee Sunday, the so-called supermoon, so it’s moving faster in its orbit than average.  Like the Sun, the Moon always appears orange or red near the horizon.

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

Addendum

Path of the Harvest Moon

The positions of the Moon from September 28 to October 1, 2015. Note the path of the Moon. At Harvest Moon in northern Michigan time it makes less than a 45 degree angle with the horizon. For other latitudes it’s less than (90 – latitude). shorthand term for 90 – latitude is co-latitude. Created using Cartes du Ciel.

The closer to horizontal the Moon’s path is the shorter the difference in night-to-night rise times.

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09/24/2015 – Ephemeris – Looking forward to Sunday’s Lunar Eclipse

September 24, 2015 Comments off

Ephemeris for Thursday, September 24th.  The Sun will rise at 7:32.  It’ll be up for 12 hours and 4 minutes, setting at 7:36.   The Moon, half way from first quarter to full, will set at 4:20 tomorrow morning.

Lets check out Sunday’s total lunar eclipse.  It will be visible from the entire contiguous United States, and in its entirety from Colorado, eastward.  The partial phase will start at 9:07 p.m.  The total phase will begin at 10:11 p.m. and extend to 11:23 p.m. when the ending partial phase will start.  The eclipse will end at 12:27 a.m.  The eclipse is perfectly viewable with the naked eye or binoculars.  For those who want company and commentary as to what’s going on, the Grand Traverse Astronomical Society will provide two venues from which to view the eclipse:  The Northwestern Michigan College’s Rogers Observatory, south of Traverse City on Birmley Rd. and Platte River Point at the end of Lake Michigan Road off M22, part of the Sleeping Bear Dunes National Lakeshore, weather permitting.

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

Addendum

The following is an excerpt from my September 1 post.

Lunar Eclipse Diagram

The eclipse occurs on the 28th for Universal Time. It’s the evening of the 27th for us. The Moon travels through the Earth’s shadow from right to left. What are seen are points of contact with the shadow and mid-eclipse. From Five Millennium Canon of Lunar Eclipses (Espenak & Meeus) NASA.

Contact times are labeled P1, U1, U2, U3, U4, and P4.  P2 and P3 are omitted because they are synonymous with U1 and U4 respectively:

  • P1 – 8:11:47 p.m. Enter the penumbra (unseen).  By about 8:30 the duskiness on the left edge of the moon will start to be noticeable.
  • U1 – 9:07:11 p.m. Enter the umbra (partial eclipse begins).
  • U2 – 10:11:10 p.m. Totality begins.
  • Mid eclipse 10:48:17 p.m.
  • U3 – 11:23:05 p.m. Totality ends, egress partial phase begins.
  • U4 – 12:27:03 a.m. Partial phase ends.  The Moon’s upper right edge should appear dusky for the next half hour or so.
  • P4 – 1:22:27 a.m.  Penumbral phase ends (unseen).

Note:  The duskiness of the penumbral phase of the eclipse can be enhanced by viewing through sunglasses.

During the total phase, light leaks in around the Earth due to the bending of light in the Earth’s atmosphere, so the Moon is illuminated by the collective sunrises and sunsets around the globe.  This usually gives the Moon a coppery hue, that some are now calling a blood moon.  Occasionally, due to volcanic eruptions the Moon can become very dark.

This full moon is also the Harvest Moon and for those who care, a supermoon, it having reached perigee earlier that day.

Weather permitting there will be two GTAS venues to view this eclipse.  The first will be the NMC Rogers Observatory.  The second will be at the Sleeping Bear Dunes National Lakeshore at Platte River Point at the end of Lake Michigan Road.  The site will be open for the visible parts of the eclipse from 9 p.m. to 12:30 a.m.

There’s a severe geomagnetic storm in progress at 7 p.m. EDT (23:00 UT) June 22, 2015

June 22, 2015 Comments off

There’s a good chance for auroras (northern/southern lights) tonight at moderate latitudes.  In Michigan: we’re under clouds now.  Skies may clear by midnight for the west side of the lower peninsula of Michigan according to Anttilla Danko’s Clear Sky Charts, such as this for the Lanphier Observatory in Glen Arbor.  Also check spaceweather.com

Categories: Uncategorized

03/16/2015 – Ephemeris – The bright star Aldebaran

March 16, 2015 Comments off

Ephemeris for Monday, March 16th.  The Sun will rise at 7:53.  It’ll be up for 11 hours and 56 minutes, setting at 7:49.   The Moon, 3 days past last quarter, will rise at 5:57 tomorrow morning.

The constellation Orion, is in the south-southwest at 9 p.m.  To the right of it, in the southwest is Taurus the bull.  The bright orange star in Taurus is Aldebaran.  Aldebaran appears at the upper left tip of a letter V group of stars that is the face of the bull.  Aldebaran isn’t actually part of the group, called the Hyades star cluster.  The cluster is about 151 light years away, while Aldebaran is 65.  The star has an orange hue because its surface is cooler than the sun’s.  However Aldebaran is 44 times larger in diameter, and shines 518 times brighter than the sun.  The name Aldebaran means “Follower”  because it follows the Pleiade star cluster through the skies.  The Pleiades are to the right of Aldebaran.

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

Addendum

Aldebaran

Aldebaran, the Hyades, of Taurus, Orion and the Pleiades. Created using Stellarium.

Categories: Uncategorized

2014 in review

December 30, 2014 Comments off

The WordPress.com stats helper monkeys prepared a 2014 annual report for this blog.

Here’s an excerpt:

The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 59,000 times in 2014. If it were a concert at Sydney Opera House, it would take about 22 sold-out performances for that many people to see it.

Click here to see the complete report.

Categories: Uncategorized

2013 in review

December 31, 2013 Comments off

The WordPress.com stats helper monkeys prepared a 2013 annual report for this blog.

Here’s an excerpt:

The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 31,000 times in 2013. If it were a concert at Sydney Opera House, it would take about 11 sold-out performances for that many people to see it.

Click here to see the complete report.

Categories: Uncategorized

07/02/2013 – Ephemeris – Lyra the harp in Greek mythology

July 2, 2013 Comments off

Ephemeris for Tuesday, July 2nd.  Today the sun will be up for 15 hours and 29 minutes, setting at 9:31.   The moon, 2 days past last quarter, will rise at 2:45 tomorrow morning.  Tomorrow the sun will rise at 6:02.

High in the east at 11 p.m. can be found a bright star just above a small, narrow, but very distinctive parallelogram of stars.  They are the stars of the constellation Lyra the harp.  The bright star is Vega the 5th brightest night-time star.  To the Romans the star Vega represented a falling eagle or vulture.  Apparently they never made the distinction between the two.  It is a pure white star and serves as a calibration star for color and brightness.  The harp, according to Greek mythology, was invented by the god Hermes.  The form of the harp in the sky, is as he had invented it: by stretching strings across a tortoise-shell.  Hermes gave it to his half-brother Apollo, who in turn gave it to the great musician Orpheus.

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

Addendum

Lyra

Lyra as a tortoise-shell harp. Created using Stellarium and free clip art.

Annotated Lyra:

Lyra

Magnified view of Lyra. Created using Stellarium.