Archive
09/30/2016 – Ephemeris – Looking ahead to October skies
Ephemeris for Friday, September 30th. The Sun will rise at 7:40. It’ll be up for 11 hours and 44 minutes, setting at 7:24. The Moon is new today, and won’t be visible.
Let’s look at the skies for the month of October. The sun will still be moving south rapidly. Daylight hours in the Interlochen/Traverse City area and will drop from 11 hours and 41 minutes tomorrow to 10 hours, 12 minutes at month’s end.. The altitude of the sun above the southern horizon at local noon will be 42 degrees tomorrow, and will descend to 31 degrees on Halloween, also in the Interlochen area. The Straits area will have the sun a degree lower. Local noon, when the sun is due south will be about 1:30 p.m. Sunrise times will increase from 7:41 tomorrow all the way to 8:20 a.m. in Interlochen and Traverse City on the 31st. Sunset times will decrease from 7:22 p.m. tomorrow to 6:32 when the trick-or-treaters haunt our neighborhoods on Halloween.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
October Star Chart
Star Chart for October 2016. Created using my LookingUp program. To enlarge in Firefox right-click on image then click View image.
The planets and stars are plotted for the 15th at 9 p.m. EDT. That is chart time. Note, Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian.) To duplicate the star positions on a planisphere you may have to set it to 1:45 earlier than the current time if you are near your time meridian.
Evening nautical twilight ends at 8:25 p.m. EDT on the 1st, decreasing to 7:37 p.m. EDT on the 31st.
Morning nautical twilight starts at 6:38 a.m. EDT on the 1st, and increasing to 7:15 a.m. EDT on the 31st.
Add a half hour to the chart time every week before the 15th and subtract a half hour for every week after the 15th.
For a list of constellation names to go with the abbreviations click here.
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star
- Follow the arc of the handle of the Big Dipper to the star Arcturus
- The Summer Triangle is outlined in red. Vega in Lyra (Lyr), Deneb in Cygnus (Cyg) and Altair in Aquila (Aql).
Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Time.
Date Time Event Oct 01 Sa Venus: 30.9° E 03 Mo 1:30 pm Moon-Venus: 5.6° S 04 Tu 7:02 am Moon Apogee: 406100 km 06 Th 4:04 am Moon-Saturn: 4.2° S 08 Sa 2:03 am Moon South Dec.: 18.5° S 09 Su 12:33 am First Quarter 13 Th 5:43 am Moon Descending Node 15 Sa 6:15 am Uranus Opposition 16 Su 12:23 am Full Moon 16 Su 7:36 pm Moon Perigee: 357900 km 19 We 2:18 pm Moon-Aldebaran: 0.3° S 20 Th 7:38 pm Moon North Dec.: 18.6° N 21 Fr 12:45 am Orionid Shower: ZHR = 20 22 Sa 3:14 pm Last Quarter 25 Tu 12:01 am Moon-Regulus: 1.7° N 25 Tu 9:45 pm Moon Ascending Node 26 We 6:54 am Venus-Antares: 3.1° N 27 Th 11:53 am Mercury Superior Conj. 28 Fr 5:33 am Moon-Jupiter: 1.6° S 29 Sa 9:47 pm Venus-Saturn: 3° N 30 Su 12:38 pm New Moon 31 Mo 2:29 pm Moon Apogee: 406700 km Nov 01 Tu Venus: 37.7° E
09/29/2016 – Ephemeris – The Rosetta spacecraft starts its fatal dive today
Ephemeris for Thursday, September 29th. The Sun will rise at 7:38. It’ll be up for 11 hours and 47 minutes, setting at 7:26. The Moon, 1 day before new, will rise at 7:09 tomorrow morning.
Tomorrow morning at 6:40 a.m. give or take 20 minutes the European Space Agency’s Rosetta spacecraft will slowly crash into Comet 67P/Churyumov-Gerasimenko after orbiting it for a bit over 2 years. The comet is carrying Rosette out toward Jupiter’s orbit where the spacecraft cannot receive enough sunlight to power it. Today the controllers will command the spacecraft to perform the collision maneuver to cancel Rosetta’s complete orbital velocity and let it fall straight down to hit the head of the rubber ducky shaped comet. It’s antenna will be facing Earth and it will be taking pictures all the way down for immediate transmission because Rosetta will turn off its transmitter forever when it impacts the comet.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
An artist’s illustration of the European Space Agency’s comet-chasing Rosetta spacecraft. Credit: ESA – C. Carreau
Rosetta, Final orbit. Credit & copyright European Space Agency (ESA)
09/28/2016 – Ephemeris – Then there were three
Ephemeris for Wednesday, September 28th. The Sun will rise at 7:37. It’ll be up for 11 hours and 50 minutes, setting at 7:27. The Moon, 2 days before new, will rise at 6:09 tomorrow morning.
Mercury will pass its greatest separation from the Sun in the morning sky later this afternoon and will be visible in the morning sky in the east for the next week or so. It’s now visible in the morning twilight and it will rise at 6:04 tomorrow morning with the moon below it. Venus, Saturn and Mars are in the evening sky. Venus is briefly visible after sunset, low in the west. It will set at 8:33 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 and Antares below. Mars is way out to the left of the other two. Saturn, spectacular in telescopes with its rings, will set at 10:26 p.m. Mars will set at 11:23 p.m.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mercury animation for two mornings, 9/28/16 and 9/29/16 at 6:40 a.m., about 36 minutes after sunrise. Note that the Moon is shown at two times its actual size. Created using Stellarium and GIMP.
Looking very low in the west at 7:47 p.m., 20 minutes after sunset, September 28, 2016. Venus is approaching Saturn, which is probably not really visible in the bright twilight. 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 28, 2016. Created using Stellarium.
Saturn and some of its moons at 9 p.m. September 28, 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 28, 2016. The night ends on the left with sunrise on September 29. 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.
09/27/2016 – Ephemeris – The princess Pegasus helped save
Ephemeris for Tuesday, September 27th. The Sun will rise at 7:36. It’ll be up for 11 hours and 53 minutes, setting at 7:29. The Moon, 3 days before new, will rise at 5:08 tomorrow morning.
In the east at 9 this evening can be found a large square of stars standing on one corner, the Great Square of Pegasus the flying horse. What look like its hind legs stretching to the left from the left corner star is another constellation, Andromeda the chained princess. She is seen in the sky as two diverging upward curving strings of three stars each. She was rescued by the hero Perseus, a nearby constellation, riding Pegasus. Andromeda’s claim to astronomical fame is the large galaxy seen with the unaided eye just above the upper line of stars, the Great Andromeda Galaxy, 2.5 million light years away. To the unaided eye the galaxy appears as a small smudge of light. In binoculars the galaxy is a delicate spindle of light.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Andromeda, Pegasus and Perseus in the east. Created using Stellarium.
I added some constellation lines to Andromeda since yesterday to match the transcript and how I see her. Looks like I have some work to do with Perseus, before I talk about him later on. He doesn’t look like a chicken enough. I’m going for laughs here.
Andromeda. Pegasus and Perseus in the east. Created using Stellarium, art by Johan Meuris.
09/26/2016 – Ephemeris – Pegasus flies through autumn skies
Ephemeris for Monday, September 26th. The Sun will rise at 7:35. It’ll be up for 11 hours and 56 minutes, setting at 7:31. The Moon, 3 days past last quarter, will rise at 4:05 tomorrow morning.
Rising and almost half way up the sky in the east at as it gets dark around 9 p.m. can be found one of the great autumn constellations: Pegasus the flying horse of Greek myth. Its most visible feature is a large square of four stars, now standing on one corner. This feature, called the Great Square of Pegasus, represents the front part of the horse’s body. The horse is quite aerobatic, because it is seen flying upside down. Remembering that fact, the neck and head is a bent line of stars emanating from the right corner star of the square. Its front legs can be seen in a gallop extending to the upper right from the top star of the square. From the left star extend, not hind legs but the constellation of Andromeda, rescued with the help of Pegasus.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Pegasus and Andromeda in the east. Created using Stellarium.
Pegasus and Andromeda in the east. Created using Stellarium, art by Johan Meuris.
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.
Bob Moler's Ephemeris Blog 