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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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07/04/2014 – Ephemeris – Find patriotic red, white and blue stars

July 4, 2014 Comments off

Ephemeris for Independence Day, Friday, July 4th.  Today the sun will be up for 15 hours and 27 minutes, setting at 9:30.   The moon, 1 day before first quarter, will set at 1:03 tomorrow morning.  Tomorrow the sun will rise at 6:03.

On this patriotic day let’s look for some red, white, and blue stars.  Red is easy, the red star Antares is seen in the south at 11 p.m.  Mars, the red planet, in the southwest, can be added even though it’s not technically a star.  White is easy too, the official white calibration star Vega high in the east at 11 p.m.  The blue star is really blue-white.  The brightest of these out at 11 p.m. is Spica, low in the southwest.  The color is best seen in binoculars.  Star colors are quite subtle, and are an indicator of the temperature of their outer gaseous layers.  The temperature of a stars outer layers, in order of their increasing temperatures, red, white and blue, is not related to the temperature in their cores.  Of these three the coolest on the outside, Antares is really the hottest inside, using helium as fuel.

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

Addendum

Red white and blue stars

Red white and blue stars for Independence Day at 11 p.m. on July 4, 2014. Created using Stellarium.