09/23/2016 – Ephemeris – Solar observing available at the Acme Fall Festival tomorrow

Ephemeris for Friday, September 23rd.  The Sun will rise at 7:31.  It’ll be up for 12 hours and 5 minutes, setting at 7:37.  The Moon, at last quarter today, will rise at 1:02 tomorrow morning.

Tomorrow members of the Grand Traverse Astronomical Society will be at the Acme Fall Festival at the Flintfields Horse Park, 6535 Bates Rd., just north of M72 from 10 a.m. to 5 p.m.  Members will be viewing the Sun with telescopes equipped with solar filters and a special solar telescope which can view the Sun in the light of just the element hydrogen to see solar structures just above the bright ball of the Sun we usually see. This requires clear skies.  The fat waning crescent moon should also be visible in the morning.  Besides viewing the society will have displays showing the wonders of the heavens.  Members will be there to answer your questions about astronomy and telescopes.

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

09/22/2016 – Ephemeris – Autumn will begin this morning

Ephemeris for Thursday, September 22nd.  The Sun will rise at 7:30.  It’ll be up for 12 hours and 8 minutes, setting at 7:39.  The Moon, 1 day before last quarter, will rise at 12:06 tomorrow morning.

Fall is about to a, well… fall upon us and in a few weeks so will the leaves.  At 10:21 (14:21 UT) this morning the Sun will cross the celestial equator heading south.  The celestial equator is an imaginary line in the sky above the earth’s equator.  At that point the sun will theoretically set at the north pole and rise at the south pole.  The day is called the autumnal equinox and the daylight hours today is 12 hours and 8 minutes instead of 12 hours exactly.  That’s due to our atmosphere and our definition of sunrise and sunset.  The reason for the cooler weather now and the cold weather this winter is that the length of daylight is shortening, and the Sun rides lower in the sky, spreading its heat over a larger area, thus diluting its intensity.

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

Addendum

The Earth as seen a couple of days ago from NOAA,s DSCOVR satellite located near the Sun-Earth L-1 point 1 million miles sunward from the Earth. Credit NOAA/NASA.

The Sun’s path through the sky on the equinox day from Traverse City, MI. Created using my LookingUp program.

 

09/21/2016 – Ephemeris – Mercury escaped to the morning sky and Jupiter will soon follow

Ephemeris for Wednesday, September 21st.  The Sun will rise at 7:29.  It’ll be up for 12 hours and 11 minutes, setting at 7:41.  The Moon, 2 days before last quarter, will rise at 11:15 this evening.

Tonight we have four of the five bright classical planets in the evening sky.  Mercury crossed into the morning sky last week, and Jupiter will follow next Monday.  Jupiter is too close to the Sun to be seen.  We are left with Venus, Saturn and Mars. Venus is briefly visible after sunset, low in the west.  It will set at 8:42 p.m., following the Sun’s earlier setting times.  Mars, Saturn and the star Antares start the evening in the southwestern sky in a lengthening triangle, with Saturn on top, Mars below and way out to the left, and Antares below Saturn.  Saturn, spectacular in telescopes with its rings, will set at 10:52 p.m.  And Mars, moving rapidly to the east against the stars will set at 11:31 p.m.

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

Addendum

Looking very low in the west at 8:01 p.m., 20 minutes after sunset, September 21, 2016. To see how Venus’ position changes from week to week, check out the last few Wednesday’s posts. I’m using the same landscape for each which is supplied by Stellarium. Created using Stellarium.

The lengthening Mars-Saturn-Antares triangle and the background constellations at 9 p.m., September 21, 2016. Created using Stellarium.

Saturn and some of its moons at 9 p.m. September 21, 2016. Created using Cartes du Ciel (Sky Charts).

Planets and Moon at sunset and sunrise of a single night starting with sunset on the right on September 21, 2016. The night ends on the left with sunrise on September 22. Mercury has escaped to the Morning sky and will rise at 614 a.m. on the 22nd. If you are using Firefox right-click on the image and select View Image to enlarge the image. That goes for all the large images. Created using my LookingUp program.

09/20/2016 – Ephemeris – The twilight zone

Ephemeris for Tuesday, September 20th.  The Sun will rise at 7:28.  It’ll be up for 12 hours and 14 minutes, setting at 7:43.  The Moon, 3 days before last quarter, will rise at 10:29 this evening.

It’s getting a lot darker a lot earlier now than it did a month or so ago.  We see the same thing in the morning sky.  Now astronomical twilight, that’s when the last vestiges of the twilight glow disappear, ends before the time of sunset we had back in June.  Tonight that’s at 9:21 p.m., when the Sun reaches 18 degrees below the horizon.  Useful stargazing usually starts by nautical twilight which will occur at 8:46 p.m. when the Sun is 12 degrees down.  This is the time when navigators could see the bright stars and the horizon with their sextants to make a star fix.  It is a time when all the naked eye planets and the brighter constellations can be made out.   Twilight lasts the longest near the summer solstice due to the shallow angle of the Sun’s setting path.

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

Addendum

Below is the twilight table for September through December.  This is a calendar function from Cartes du Ciel (Sky Charts), a free program, which can be downloaded from the panel on the right of this page.  This is, of course, for the Interlochen/Traverse City, Michigan area.  If you’re from somewhere else, download the program, and put in your location to create your own table.  The last two columns on the right are times that the sky will be dark, without moonlight.

Interlochen/ Traverse City			Time zone=EDT/EST
	Morning twilight		Evening twilight		Dark night
Date	Astronomical	Nautical	Nautical	Astronomical	Start	End
2016-09-01	5h26m	6h04m	21h27m	22h05m	22h05m	5h26m
2016-09-02	5h28m	6h06m	21h25m	22h03m	22h03m	5h28m
2016-09-03	5h29m	6h07m	21h23m	22h01m	22h01m	5h29m
2016-09-04	5h31m	6h09m	21h21m	21h59m	21h59m	5h31m
2016-09-05	5h33m	6h10m	21h19m	21h56m	22h24m	5h33m
2016-09-06	5h34m	6h11m	21h17m	21h54m	22h55m	5h34m
2016-09-07	5h36m	6h13m	21h15m	21h52m	23h29m	5h36m
2016-09-08	5h37m	6h14m	21h13m	21h50m	–	5h37m
2016-09-09	5h39m	6h15m	21h11m	21h48m	0h07m	5h39m
2016-09-10	5h40m	6h17m	21h09m	21h45m	0h50m	5h40m
2016-09-11	5h42m	6h18m	21h07m	21h43m	1h39m	5h42m
2016-09-12	5h43m	6h19m	21h05m	21h41m	2h34m	5h43m
2016-09-13	5h44m	6h20m	21h03m	21h39m	3h35m	5h44m
2016-09-14	5h46m	6h22m	21h01m	21h37m	4h40m	5h46m
2016-09-15	5h47m	6h23m	20h59m	21h35m	–	–
2016-09-16	5h49m	6h24m	20h57m	21h33m	–	–
2016-09-17	5h50m	6h26m	20h55m	21h31m	–	–
2016-09-18	5h51m	6h27m	20h53m	21h28m	–	–
2016-09-19	5h53m	6h28m	20h51m	21h26m	21h26m	21h47m
2016-09-20	5h54m	6h29m	20h49m	21h24m	21h24m	22h28m
2016-09-21	5h56m	6h31m	20h47m	21h22m	21h22m	23h15m
2016-09-22	5h57m	6h32m	20h45m	21h20m	21h20m	–
2016-09-23	5h58m	6h33m	20h43m	21h18m	21h18m	0h06m
2016-09-24	6h00m	6h34m	20h41m	21h16m	21h16m	1h02m
2016-09-25	6h01m	6h36m	20h39m	21h14m	21h14m	2h01m
2016-09-26	6h02m	6h37m	20h37m	21h12m	21h12m	3h03m
2016-09-27	6h04m	6h38m	20h36m	21h10m	21h10m	4h05m
2016-09-28	6h05m	6h39m	20h34m	21h08m	21h08m	5h08m
2016-09-29	6h06m	6h41m	20h32m	21h06m	21h06m	6h06m
2016-09-30	6h08m	6h42m	20h30m	21h04m	21h04m	6h08m
2016-10-01	6h09m	6h43m	20h28m	21h02m	21h02m	6h09m
2016-10-02	6h10m	6h44m	20h26m	21h00m	21h00m	6h10m
2016-10-03	6h11m	6h45m	20h24m	20h58m	20h58m	6h11m
2016-10-04	6h13m	6h47m	20h22m	20h56m	21h28m	6h13m
2016-10-05	6h14m	6h48m	20h21m	20h55m	22h04m	6h14m
2016-10-06	6h15m	6h49m	20h19m	20h53m	22h45m	6h15m
2016-10-07	6h16m	6h50m	20h17m	20h51m	23h31m	6h16m
2016-10-08	6h18m	6h52m	20h15m	20h49m	–	6h18m
2016-10-09	6h19m	6h53m	20h14m	20h47m	0h21m	6h19m
2016-10-10	6h20m	6h54m	20h12m	20h46m	1h19m	6h20m
2016-10-11	6h21m	6h55m	20h10m	20h44m	2h20m	6h21m
2016-10-12	6h23m	6h56m	20h08m	20h42m	3h26m	6h23m
2016-10-13	6h24m	6h58m	20h07m	20h40m	4h36m	6h24m
2016-10-14	6h25m	6h59m	20h05m	20h39m	5h49m	6h25m
2016-10-15	6h26m	7h00m	20h03m	20h37m	–	–
2016-10-16	6h28m	7h01m	20h02m	20h35m	–	–
2016-10-17	6h29m	7h03m	20h00m	20h34m	–	–
2016-10-18	6h30m	7h04m	19h58m	20h32m	20h32m	21h07m
2016-10-19	6h31m	7h05m	19h57m	20h31m	20h31m	21h58m
2016-10-20	6h33m	7h06m	19h55m	20h29m	20h29m	22h54m
2016-10-21	6h34m	7h07m	19h54m	20h27m	20h27m	23h54m
2016-10-22	6h35m	7h09m	19h52m	20h26m	20h26m	–
2016-10-23	6h36m	7h10m	19h51m	20h24m	20h24m	0h56m
2016-10-24	6h37m	7h11m	19h49m	20h23m	20h23m	1h59m
2016-10-25	6h39m	7h12m	19h48m	20h22m	20h22m	3h01m
2016-10-26	6h40m	7h14m	19h46m	20h20m	20h20m	4h02m
2016-10-27	6h41m	7h15m	19h45m	20h19m	20h19m	5h02m
2016-10-28	6h42m	7h16m	19h44m	20h17m	20h17m	6h02m
2016-10-29	6h43m	7h17m	19h42m	20h16m	20h16m	6h43m
2016-10-30	6h45m	7h18m	19h41m	20h15m	20h15m	6h45m
2016-10-31	6h46m	7h20m	19h40m	20h14m	20h14m	6h46m
2016-11-01	6h47m	7h21m	19h38m	20h12m	20h12m	6h47m
2016-11-02	6h48m	7h22m	19h37m	20h11m	20h42m	6h48m
2016-11-03	6h49m	7h23m	19h36m	20h10m	21h26m	6h49m
2016-11-04	6h51m	7h24m	19h35m	20h09m	22h14m	6h51m
2016-11-05	6h52m	7h26m	19h34m	20h08m	23h08m	6h52m
2016-11-06	5h53m	6h27m	18h33m	19h07m	23h07m	5h53m
2016-11-07	5h54m	6h28m	18h31m	19h06m	–	5h54m
2016-11-08	5h55m	6h29m	18h30m	19h04m	0h09m	5h55m
2016-11-09	5h56m	6h31m	18h29m	19h03m	1h15m	5h56m
2016-11-10	5h58m	6h32m	18h28m	19h03m	2h24m	5h58m
2016-11-11	5h59m	6h33m	18h27m	19h02m	3h36m	5h59m
2016-11-12	6h00m	6h34m	18h26m	19h01m	4h50m	6h00m
2016-11-13	6h01m	6h35m	18h26m	19h00m	–	–
2016-11-14	6h02m	6h36m	18h25m	18h59m	–	–
2016-11-15	6h03m	6h38m	18h24m	18h58m	–	–
2016-11-16	6h04m	6h39m	18h23m	18h57m	18h57m	19h38m
2016-11-17	6h06m	6h40m	18h22m	18h57m	18h57m	20h39m
2016-11-18	6h07m	6h41m	18h22m	18h56m	18h56m	21h43m
2016-11-19	6h08m	6h42m	18h21m	18h55m	18h55m	22h47m
2016-11-20	6h09m	6h43m	18h20m	18h55m	18h55m	23h52m
2016-11-21	6h10m	6h45m	18h20m	18h54m	18h54m	–
2016-11-22	6h11m	6h46m	18h19m	18h54m	18h54m	0h54m
2016-11-23	6h12m	6h47m	18h18m	18h53m	18h53m	1h56m
2016-11-24	6h13m	6h48m	18h18m	18h53m	18h53m	2h55m
2016-11-25	6h14m	6h49m	18h17m	18h52m	18h52m	3h54m
2016-11-26	6h15m	6h50m	18h17m	18h52m	18h52m	4h52m
2016-11-27	6h16m	6h51m	18h17m	18h52m	18h52m	5h51m
2016-11-28	6h17m	6h52m	18h16m	18h51m	18h51m	6h17m
2016-11-29	6h18m	6h53m	18h16m	18h51m	18h51m	6h18m
2016-11-30	6h19m	6h54m	18h16m	18h51m	18h51m	6h19m
2016-12-01	6h20m	6h55m	18h15m	18h50m	19h11m	6h20m
2016-12-02	6h21m	6h56m	18h15m	18h50m	20h03m	6h21m
2016-12-03	6h22m	6h57m	18h15m	18h50m	20h59m	6h22m
2016-12-04	6h23m	6h58m	18h15m	18h50m	22h00m	6h23m
2016-12-05	6h24m	6h59m	18h15m	18h50m	23h03m	6h24m
2016-12-06	6h25m	7h00m	18h15m	18h50m	–	6h25m
2016-12-07	6h26m	7h01m	18h15m	18h50m	0h08m	6h26m
2016-12-08	6h26m	7h02m	18h15m	18h50m	1h17m	6h26m
2016-12-09	6h27m	7h03m	18h15m	18h50m	2h26m	6h27m
2016-12-10	6h28m	7h03m	18h15m	18h50m	3h40m	6h28m
2016-12-11	6h29m	7h04m	18h15m	18h50m	4h54m	6h29m
2016-12-12	6h30m	7h05m	18h15m	18h51m	6h09m	6h30m
2016-12-13	6h30m	7h06m	18h15m	18h51m	–	–
2016-12-14	6h31m	7h06m	18h16m	18h51m	–	–
2016-12-15	6h32m	7h07m	18h16m	18h51m	18h51m	19h21m
2016-12-16	6h32m	7h08m	18h16m	18h52m	18h52m	20h28m
2016-12-17	6h29m	7h04m	18h13m	18h48m	18h48m	21h35m
2016-12-18	6h30m	7h05m	18h13m	18h48m	18h48m	22h40m
2016-12-19	6h30m	7h06m	18h13m	18h49m	18h49m	23h44m
2016-12-20	6h31m	7h06m	18h14m	18h49m	18h49m	–
2016-12-21	6h31m	7h07m	18h14m	18h50m	18h50m	0h45m
2016-12-22	6h32m	7h07m	18h15m	18h50m	18h50m	1h46m
2016-12-23	6h32m	7h07m	18h15m	18h51m	18h51m	2h44m
2016-12-24	6h32m	7h08m	18h16m	18h51m	18h51m	3h43m
2016-12-25	6h33m	7h08m	18h17m	18h52m	18h52m	4h40m
2016-12-26	6h33m	7h09m	18h17m	18h53m	18h53m	5h37m
2016-12-27	6h34m	7h09m	18h18m	18h53m	18h53m	6h32m
2016-12-28	6h34m	7h09m	18h19m	18h54m	18h54m	6h34m
2016-12-29	6h34m	7h09m	18h19m	18h55m	18h55m	6h34m
2016-12-30	6h34m	7h10m	18h20m	18h56m	18h56m	6h34m
2016-12-31	6h34m	7h10m	18h21m	18h56m	19h53m	6h34m

09/19/2016 – Ephemeris – How did the pirates of long ago navigate?

Aye matey, Barnacle Bob here with Ephemeris for Talk Like a Pirate Day, Monday, September 19th.  The Sun will rise at 7:26.  It’ll be up for 12 hours and 17 minutes, setting at 7:44.  The Moon, 3 days past full, will rise at 9:47 this evening.

We tend to romanticize things of the past like the Pirates of the 16th, 17th and 18th century, not so much the Somali pirates of today.  The problems of getting around and finding your way around were difficult in the seas and oceans before the use of the Harrison Chronometer made the precise determination of longitude possible in the late 18th century.  It did require an almanac of star and planet positions plus the chronometer must be set to some time standard of a particular place of known longitude.  Among the Islands of the Caribbean I imagine, though don’t know for certain, that one could dead recon between the islands and crudely navigate that way.  Latitude determination was easy using the Sun.

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

Addendum

John Harrison’s (1693-1776) First attempt at a chronometer (1735), which he called H1. Credit: Solarnavigator.net.

John Harrison’s (1693-1776) fourth attempt at a chronometer (1759), which he called H4. It passed its sea trials. It’s not much bigger than a pocket watch.  Credit: Solarnavigator.net.

 

09/16/2016 – Ephemeris – The Harvest Moon is slightly eclipsed for everyone but the Americas

Ephemeris for Friday, September 16th.  The Sun will rise at 7:23.  It’ll be up for 12 hours and 27 minutes, setting at 7:50.  The Moon, at full today, will rise at 7:59 this evening.

Tonight’s full Moon is the Harvest Moon, the nearest full Moon to the autumnal equinox.  For the next few nights the Moon will rise later each night by much less than the average 50 minutes later each night effectively lengthening twilight for those gathering in crops.  Also this afternoon there will be a penumbral lunar eclipse visible, well not here in Michigan… because the Moon won’t be up.   Actually just about the whole world except North America and most of South America will be able to see the eclipse.  A penumbral eclipse is what I call a 5 o’clock shadow eclipse.  You wouldn’t know it unless someone pointed it out to you, when the Moon dips into the Earth’s outer shadow and the sunlight falling part of it is diminished by a little bit.

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

Addendum

The not so full Moon of Monday night and its reflection on the waters of Suttons Bay after the schooner Inland Seas docked after an evening sail. Credit: the author.

The penumbral eclipse of the Moon centered on 2:25 p.m. Eastern time, 18:54 UT, for an hour and a half before and after. Only near the middle of the eclipse will anything be visible of the effect. I find that wearing sunglasses reduces the brightness of the moon and enhances the penumbral shadow. Credit: NASA/GSFC/ Fred Espenak.

For the full-page pdf of the above click here: http://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2016Sep16N.pdf

09/15/2016 – Ephemeris – SpaceX has an explosion in its Falcon 9 second stage

Ephemeris for Thursday, September 15th.  The Sun will rise at 7:22.  It’ll be up for 12 hours and 30 minutes, setting at 7:52.  The Moon, 1 day before full, will set at 7:01 tomorrow morning.

The rocket company SpaceX had one of its Falcon 9 Rockets explode as it was being fueled for a test firing to check out its booster engines on September first.  The second stage, which was being loaded with fuel exploded.  Even if a tank had been ruptured, there should be no ignition source to cause the explosion.  Unfortunately the satellite, AMOS-6 a communications satellite destined for geosynchronous orbit, was already mounted on the rocket, and can be seen falling off the rocket just after the explosion.  This is the second failure of a Falcon 9.  In June of last year a helium tank inside the liquid oxygen tank in the second stage broke loose and ruptured the tank, while still being boosted by the first stage.  It took a few seconds after the rupture before the fuel ignited causing the explosion that ended the mission.  SpaceX has issued a request for videos or anything that might shed light on the latter accident.

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

Addendum

A sequence of photographs of the Falcon 9 explosion. Credit: US Launch Report.