07/31/2012 – Ephemeris – Previewing August Skies

Ephemeris for Tuesday, July 31st.  The sun rises at 6:28.  It’ll be up for 14 hours and 40 minutes, setting at 9:08.   The moon, 1 day before full, will set at 5:59 tomorrow morning.

Let’s look ahead at the month of August in the skies which begins tomorrow.  Daylight hours will decrease from 14 hours and 37 minutes tomorrow to 13 hours 15 minutes on the 31st.  The altitude of the sun at local noon, that is degrees of angle above the horizon will decrease from 63 degrees today to just over 53 degrees on the 31st.  Straits area listeners can subtract one more degree from those angles.  Local noon, when the sun is due south, is about 1:43 p.m.  The big event of the month will be the Perseid meteor shower will reach its peak on Sunday morning the 12th.  Head out as soon as it gets dark, about 10:30 Saturday evening to watch the show.  At that early hour the meteors may be few, but they will leave long tails in the sky, coming from the northeast.  [Later as the meteor source or radiant rises more and more meteors will be visible.]

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

 

07/30/2012 – Ephemeris – A closeup look at the bright star Deneb

Ephemeris for Monday, July 30th.  The sun rises at 6:27.  It’ll be up for 14 hours and 42 minutes, setting at 9:09.   The moon, 2 days before full, will set at 4:47 tomorrow morning.

At 10:30 this evening the bright star Deneb in Cygnus the swan will be high in the east in the tail of Cygnus the swan.  Deneb is the dimmest star of the summer triangle.  Of the other stars of the triangle, Vega is nearly overhead, and Altair to the south.  While Deneb’s apparent magnitude, or brightness as seen from earth, makes it the dimmest of the three bright stars, Deneb’s vast distance of possibly 1,500 to 2,600 light years makes it nearly 100 times the distance of Vega.  If brought as close as Vega, Deneb would be several time brighter than Venus.  For all this it is only 13-21 times the mass of the sun.  It will have an extremely short life and it will explode, go supernova, in perhaps a few million years.

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

Addendum

Summer Triangle. Created using Stellarium.

07/27/2012 – Ephemeris – I’ll be giving a presentation at the Eyaawing Museum & Culture Center in Peshawbestown tomorrow

Ephemeris for Friday, July 27th.  The sun rises at 6:24.  It’ll be up for 14 hours and 49 minutes, setting at 9:13.   The moon, 1 day past first quarter, will set at 1:41 tomorrow morning.

Tomorrow yours truly will be giving a presentation Stars and Stories of the Summer Night Skies  This will be a talk illustrated by a fantastic planetarium type program called Stellarium which is actually free from the Internet. There won’t be a planetarium dome however.  I’ll be exploring the stars and constellations visible in the summer sky and how various cultures saw them and  some of the wonderful stories of those who counted on the heavens to be their calendar in order to plant their crops and prepare for winter..  There’s the Greek constellations I tend to talk about on these programs, and others, especially those of the local Indian peoples.  The presentation is at 1 p.m. at the Eyaawing Museum and Cultural Center in Peshawbestown.

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

07/26/2012 – Ephemeris – Why is a half illuminated moon called a quarter moon?

Ephemeris for Thursday, July 26th.  The sun rises at 6:22.  It’ll be up for 14 hours and 51 minutes, setting at 9:14.   The moon, at first quarter today, will set at 12:56 tomorrow morning.

The moon was at the exact first quarter a few hours ago.  By tonight the sunlit side of the moon will be a bit fuller, but might be at the half moon phase to the casual eye.  So why do we call the half illuminated moon a quarter moon?  The moon is a quarter the way around the earth from new moon.  When it goes half way around the earth from new, we ave a fully illuminated moon from our vantage point,  Another quarter the way around we have a half illuminated moon from our vantage point, but the moon is at third quarter position or last quarter.  Another quarter way around and the moon is new again.  The ancients unlike astronomers today called the first sighting of the moon’s crescent in the west after sunset new moon.

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

Addendum

Lunar phase diagram. From Wikimedia Commons.

The arrows in the diagram is light from the sun far off to the distant right.

07/25/2012 – Ephemeris – Where are the bright planets this week?

Ephemeris for Wednesday, July 25th.  The sun rises at 6:21.  It’ll be up for 14 hours and 53 minutes, setting at 9:15.   The moon, 1 day before first quarter, will set at 12:17 tomorrow morning.

Let’s see what’s happening with the bright planets for this week.  Mars, with its unmistakable bright reddish color, is in the west southwest in the evening in the constellation of Virgo the virgin.  Mars will be setting in the west at 11:55 p.m. It is approaching Saturn and Spica just to its left.  Saturn will be in the west southwest above the bright star Spica now.  It will set at 12:32 a.m.  The moon passed the group last night as is just east of them now.  Jupiter will rise at 2:22 a.m. in the east northeast.  Venus, is now seen below Jupiter after it rises at 3:20 a.m.  Tomorrow morning, the bright star Aldebaran will appear below and right of Jupiter.  Venus is falling off to the lower left of Jupiter as Jupiter moves away from the sun.

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

Addendum

Mars, Saturn and the moon at 10:30 p.m. 07/25/2012. Created using Stellarium.

 

Jupiter and Venus with bright morning stars including those of Orion at 5:30 a.m. on 7/26/2012. Created using Stellarium.

 

07/23/2012 – Ephemeris – The star Vega up close

Ephemeris for Monday, July 23rd.  The sun rises at 6:19.  It’ll be up for 14 hours and 57 minutes, setting at 9:17.   The moon, 3 days before first quarter, will set at 11:14 this evening.

The star Vega, which is high in the east, near overhead or the zenith is a special star for astronomers.  It’s part of the small constellation or Lyra the harp, which includes the parallelogram of stars near it.  Vega is kind of a standard calibration star.  It is the 5th brightest night time star with a brightness of 0.0 magnitude, although recent measurements place it at 0.03.  Of the spectral types which  denote the star’s color and surface temperature, Vega comes out to be pure white, with a surface temperature nearly twice the sun’s.  It’s almost exactly 25 light years away, and so is one of the closer stars.  It’s a tenth the sun’s age and 40 times the sun’s brightness. [It has perhaps a Jupiter sized planet, and a Kuiper belt of Pluto like objects.]

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

Addendum

Lyra in Binoculars. Created using Stellarium.

07/24/2012 – Ephemeris – The star Antares up close

The constellation Scorpius with Antares. Created using Stellarium.

Ephemeris for Tuesday, July 24th.  The sun rises at 6:20.  It’ll be up for 14 hours and 55 minutes, setting at 9:16.   The moon, 2 days before first quarter, will set at 11:44 this evening.

Antares is a most interesting star.  It’s low in the south and red in color.  Its the heart of the Scorpius the scorpion.  Its name means Rival of Mars with which it shares its color.  Antares is a huge star, a red giant star.  Its mass is 12 times the mass of the sun, but it’s bloated out to a diameter somewhat  larger than the orbit of Mars, over 300 million miles.  This what happens to a star that has exhausted hydrogen in its core and is now fusing helium to produce energy and even more massive elements.  Its surface temperature is close to the temperature of the filament of an incandescent light bulb, about 2/3rds the temperature of the sun.  Antares also has a dim companion star.

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

07/20/2012 – Ephemeris – Astronomical events this weekend in the Grand Traverse Region

Ephemeris for Friday, July 20th.  Today the sun will be up for 15 hours and 3 minutes, setting at 9:20.   The moon, 1 day past new, will set at 9:52 this evening.  Tomorrow the sun will rise at 6:17.

This is another big weekend for the Grand Traverse Astronomical Society.  During the day tomorrow, Saturday the 21st members of the society will be in Kingsley for Kingsley Heritage Days to show the sun, if it’s clear, and have other hands on activities.  Saturday night the members will set up telescopes at the Sleeping Bear Dunes National Lakeshore for a star party.  That will start at 9 p.m. at Platte River Point at the end of Lake Michigan Road off M22 between Frankfort and Empire.  That event is weather dependent.  If that’s too far to go the Northwestern Michigan College Astronomy Club will be hosting a star party at the Rogers Observatory south of Traverse City on Birmley Road.  They will have interesting activities for the kids.

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

Addendum

One thing I omitted:  We’ll be at Friday Night Live tonight on the 200 block of Front Street in Traverse City.  Friday Night Live runs from 5:30 to 9 p.m.  We’ll be there later if its clear.  Also Kingsley Heritage Days will also be on Sunday the 22nd.

07/19/2012 – Ephemeris – The constellation Cygnus the swan

Ephemeris for Thursday, July 19th.  Today the sun will be up for 15 hours and 5 minutes, setting at 9:21.  The moon is new today, and won’t be visible.  |  Tomorrow the sun will rise at 6:16.

High in the east northeast as it gets dark flies the constellation of Cygnus the swan.  This constellation is also known as the Northern Cross.  The cross is seen lying on its side with the bright star Deneb at the head of the cross to the left.  The rest of the cross is delineated in the stars to the right.  As a swan, Deneb is the tail, the stars of the crosspiece of the cross are the leading edges of wings as Cygnus flies south through the Milky Way.  There are faint stars that also define the tips and trailing edges of its wings.  It is a very good portrayal of a flying swan, like the mute swans we see on the wing.  In Greek mythology this was the disguise of the god Zeus who seduced the young lady Leda and fathered the immortal of the Gemini twins Pollux.

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

Addendum

Cygnus and the stars of the Summer Triangle at 11 p.m. on July 19th. Created using Stellarium.

07/18/2012 – Ephemeris – Where are the bright planets this week?

Ephemeris for Wednesday, July 18th.  Today the sun will be up for 15 hours and 7 minutes, setting at 9:22.   The moon, 1 day before new, will rise at 6:53 tomorrow morning.  Tomorrow the sun will rise at 6:15.

Let’s see what’s happening with the bright planets for this week.  Mars, with its unmistakable bright reddish color, is in the west southwest in the evening in the constellation of Virgo the virgin.  Mars will be setting in the west at 12:14 a.m. It is approaching Saturn and Spica just to its left.  Saturn will be in the southwest above the bright star Spica now.  It will set at 12:59 a.m.  Jupiter, now a morning planet will rise at 2:45 a.m. in the east northeast.  Venus, is now seen just below Jupiter after it rises at 3:31 a.m.  Tomorrow morning, the bright star Aldebaran will appear between the two before twilight gets too bright before 5 a.m.  All these planets except Mars, which is too small,  are great to view in a telescope.

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

Addendum

Mars and Saturn in Virgo at 10:30 p.m. on July 18, 2012. Created using Stellarium.

Jupiter and Venus at 5 a.m. on July 19, 2012. Created using Stellarium.

Venus and Jupiter are noticeably separating.