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07/04/2017 – Ephemeris – Happy birthday America! Tomorrow morning Venus will appear near the Pleiades

July 4, 2017 1 comment

Ephemeris for Independence Day, Tuesday, July 4th. Today the Sun will be up for 15 hours and 27 minutes, setting at 9:30, and it will rise tomorrow at 6:03. The Moon, 4 days past first quarter, will set at 3:46 tomorrow morning.

This is the 241st anniversary of the signing of the Declaration of Independence. Venus is our morning star now, and back in 1776 it too was a morning planet, but a lot closer to the rising Sun, and harder to spot.

Tonight Venus will pass south of the famous Pleiades star cluster, so that tomorrow morning at about 4:30 it will be dark enough to see the Pleiades above and left of our brilliant Morning Star.

Planets to us appear as stars to the naked eye due to their distance, though they are close enough to appear as disks in small telescopes. Very few of the largest telescopes can ever see the disk of a star, other than the Sun,, and only if that star is really huge, like Betelgeuse in the winter constellation of Orion.

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

Addendum

Venus and the Pleiades

The eastern sky at 5 a.m. July 5, 2017 with the Pleiades above and left of Venus. Created using Stellarium.

We’ll be seeing the Pleiades in the evening sky in four months when summer is a memory.

July 4, 1776

The morning sky to the east and Venus about 20 minutes before sunrise that auspicious morning July 4, 1776 from Philadelphia. Created using Stellarium.

Excuse the fact that the landscape is the same in both images.

Betelgeuse disk

This is the disk of the star Betelgeuse in Orion. It is not an image from an optical telescope of an image created in submillimeter microwaves by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Credit: ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella.

Betelgeuse, though it is 600 light years away has a radius of slightly more than the orbit of Jupiter.  The bump on the left side of the image may be a plume of gas erupting from the star.

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11/27/2014 – Ephemeris – The voyage of the Mayflower

November 27, 2014 Comments off

Ephemeris for Thanksgiving Day, Thursday, November 27th.  The sun will rise at 7:54.  It’ll be up for 9 hours and 10 minutes, setting at 5:05.   The moon, 2 days before first quarter, will set at 10:51 this evening.

We are regaled with stories of the first Thanksgiving dinner between the Native Americans and the Pilgrims.  The Mayflower was headed for the Virginia Colony but were diverted by a storm.  Their first landfall in the New World was Newfoundland, where they picked up supplies.  Fulling intending to head south to Virginia, the passage became too hazardous, so they put into Cape Cod and there they stayed.  Back in those days the ship’s position was determined rather crudely.  Latitude was measured by the height of the north star and the sun at noon.  Distance and speed were measured with a log thrown overboard with a rope with knots in it.  The knots counted over a period of time gave the ship’s speed.

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

Addendum

Mayflower

Credit: Scholastic

12/25/2012 – Ephemeris – Why do we celebrate Christmas today?

December 25, 2012 Comments off

Ephemeris for Christmas Day, Tuesday, December 25th.  The sun will rise at 8:18.  It’ll be up for 8 hours and 49 minutes, setting at 5:07.   The moon, 3 days before full, will set at 6:40 tomorrow morning.

Merry Christmas.  But why is this Christmas day?  The Gospel of Luke puts Christ’s birth in the spring, during lambing season, the only time the Shepherds would be out with their flocks at night.  It is said that Christians move the birthday celebration of Jesus to a time when the Romans were naturally celebrating:  The time when the sun was going to return northward once again after the winter solstice.  Christians could celebrate in a time of general merriment.  That festival was Saturnalia.  It honored the god Saturn, the god of hospitality.  That’s quite a makeover of the Greek titan Cronos, who ate his children.  Saturn did that too, but had reformed.  The solstice was just the beginning of winter but spirits were buoyed by the return of the sun.

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

06/14/2012 – Ephemeris – Flag Day: Red, White and Blue Stars

June 14, 2012 Comments off

Ephemeris for Flag Day, Thursday, June 14th.  Today the sun will be up for 15 hours and 32 minutes, setting at 9:29.   The moon, 3 days past last quarter, will rise at 3:16 tomorrow morning.  Tomorrow the sun will rise at 5:56.

Since it’s Flag Day, lets look for some red white and blue stars.  Red is easy, I talked about it Tuesday,  It is Antares now low in the southeast in the evening in the heart of the constellation of Scorpius the scorpion.  For the white star there is no purer white star than Vega, spectral type A0 (A zero), the astronomers definition of white.  It is located midway up the sky in the east.  It is the 5th brightest night time star, and is seen off a small parallelogram of stars that make up the body of Lyra the harp.  For the blue star, the best is Spica, below Saturn this year and in the south in the evening.  It is the bluest of the 21 brightest first magnitude stars.  Color in stars is often subtle, so try to see these colors.

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

Addendum

Red (Antares), White (Vega) and Blue (Spica) stars of spring.  Created using Stellarium.

Red (Antares), White (Vega) and Blue (Spica) stars of spring. Created using Stellarium.