Archive
01/22/2019 – Ephemeris – What the heck is an ephemeris?
Ephemeris for Tuesday, January 22nd. Today the Sun will be up for 9 hours and 25 minutes, setting at 5:37, and it will rise tomorrow at 8:11. The Moon, 1 day past full, will rise at 7:41 this evening.
What the heck is an ephemeris? According to Wikipedia: “In astronomy and celestial navigation, an ephemeris (plural: ephemerides; from Latin ephemeris, meaning ‘diary’, from the Greek,… meaning ‘diary, <or> journal’) gives the positions of… astronomical objects… at a given time or times. Historically, positions were given as printed tables of values, given at regular intervals of date and time.” My tables are now databases which I generate for the year during the prior December from published algorithms. I will show all on my blog today: It’s at bobmoler.wordpress.com. (You are already here) I used to have to interpolate values from printed ephemerides.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here are sections of an ephemeris of the positions of 2014 MU69, Ultima Thule that the New Horizons flew past on New Years day. Created by JPL’s Horizons web site.
R.A. is right ascension – East-west position in the sky, like longitude on the Earth, only it’s in hours, minutes and seconds. One hour = 15 degrees.
DEC is declination – North-south position, in the sky, exactly like latitude on the Earth in degrees, minutes and seconds.
J2000.0 means that the above coordinates are based on where the vernal equinox point in the sky was on January 1, 12:00 Terrestrial Time, 2000. Or January 1, 2000, 11:58:55.816 UTC as reported in Wikipedia.
APmag – Apparent visual magnitude. Magnitudes are like golf scores. The higher magnitude the dimmer the object. It’s really, really, really dim.
delta – Distance from the Earth in terms of Astronomical Units (AU). 1 AU is Earth’s mean distance from the Sun.
deldot – The change in delta. Note that is negative. 5 days after New Horizons passed Ultima Thule that spacecraft and Ultima Thule passed behind the Sun. Now the Earth in its orbit is approaching Ultima as we are coming around the Sun.
How my data is created
I use my LookingUp for DOS program to generate sunrise/sunset, moonrise/moonset tables for the year. I also create planetary ephemeris tables here.
My Ephemeris Helper program massages the raw data from the above program to create this Almanac Master table.
The first 15 or so seconds of the Ephemeris program is created by the Ephemeris Helper program from the Almanac Master, a Holiday Table, A One Time Event Table created from NASA’s SKYCAL Calendar Table, and Reoccurring Events Table.
The Planet Master table in the Ephemeris Helper program which I use each Wednesday for planet positions.
First tab of the LookingUp for Windows program which I don’t use much for the radio program but has uses on this blog and for illustrations for the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society, that I edit, which is sent to members and distributed free via email to educators.
Source for the algorithms that I use is Astronomical Algorithms by Jean Meeus, Willmann-Bell 1991.
01/15/2019 – Ephemeris – Welcome 8:19 a.m. listeners
Ephemeris for Tuesday, January 15th. Today the Sun will be up for 9 hours and 11 minutes, setting at 5:28, and it will rise tomorrow at 8:16. The Moon, 1 day past first quarter, will set at 3:11 tomorrow morning.
Welcome to the 8:19 a.m. listeners to this program. Due to the two-hour span from the 6:19 and 8:19 airings it was thought to always give you event times in advance, which is why I’m giving tomorrow’s sunrise times. Don’t worry tomorrow’s sunrise time will never be more than 2 minutes before or after today’s. Right now, sunrise times are retreating by a half-minute a day. It’s faster in spring and fall. For more information see my blog: bobmoler.wordpress.com. Transcripts of the program are there with illustrations and additional information. And today a way to create your own sunrise and sunset calendar.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The times of rising and setting of celestial objects is accurate for only one spot on the Earth. In the case of the times I give, it’s for my house. There’s a good reason for it. I live approximately half way between Interlochen and Traverse City. In the early days I interpolated from astronomical tables in the Royal Astronomical Society of Canada’s Observers Handbook. I preferred it to the Naval Observatory’s Astronomical Almanac, which was more expensive. Anyway I had a relatively flat horizon everywhere but north, so if I climbed on the roof I could check out and verify the rising and setting times. Note that the times assume a flat sea horizon.
About accurate times: At my latitude celestial objects rise and set one minute later for each 12 1/3 miles (19.85 km) you are west of me, or a good landmark would be Traverse City West Senior High School. For every 12 1/3 miles east of there rising and setting events would be earlier by a minute. The correction for latitude or north and south isn’t that simple. See the illustration below:
These are snippets of calendars for three locations that are in a straight line from south-southwest to north-northeast in the IPR listening area. A line drawn perpendicular to it to the west-northwest is to the Sun’s setting point. Thus the setting times for all three locations are the same. However their rising times are the most divergent, as are the daylight hours.
On my Ephemeris website, not to be confused with the blog that you are now reading, I have rise and set calendars for: Cadillac, Interlochen/Traverse City (Source for times on the Ephemeris program), Ludington, Mackinaw City, Petoskey, Eagle Harbor – Keweenaw Peninsula, Houghton Lake, and Earth’s Equator at the Prime Meridian. Go Here: http://ephemeris.bjmoler.org/calendar.htm.
If you’d like these times for a different location go to the Complete Sun and Moon Data for One Day, or Sun or Moon Rise/Set Table for One Year from the United States Naval Observatory (USNO). It calculates sunrise, sunset, moonrise, moonset, and twilight for locations in the US and other locations world-wide. Note that these do not follow the changes to and from Daylight Saving Time.
05/01/2018 – Ephemeris – Previewing May Skies
Ephemeris for Tuesday, the first day of May. The Sun rises at 6:32. It’ll be up for 14 hours and 15 minutes, setting at 8:47. The Moon, 2 days past full, will rise at 10:32 this evening.
They say April showers bring May flowers, but I don’t think they meant snow showers. Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 15 minutes today to 15 hours 19 minutes on May 31st. The altitude, or angle, of the sun above the southern horizon at local noon will ascend from 60 degrees today to 67 degrees at month’s end. The altitude of the sun in the Straits area will be a degree lower than that but your length of daylight will be a few minutes longer. Local apparent noon this month, when the sun passes due south, will be about 1:38 p.m. The Eta Aquariid meteor shower will reach its peak about 3 a.m. this Saturday morning the 5th, but the bright morning Moon will interfere.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
May Evening Sky Chart
Star Chart for May 2018 (11 p.m. EDT May 15, 2018). Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 11 p.m. EDT in the evening and 5 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian during EDT and 45 minutes behind our daylight standard time meridian. during EST). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes (Daylight Time) or 45 minutes (Standard Time) earlier than the current time.
Note the chart times of 11 p.m. and 5 a.m. are for the 15th. For each week before the 15th add ½ hour (28 minutes if you’re picky). For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog.
May Morning Star Chart
Star Chart for May 2018 mornings based on 5 a.m. May 15th. Created using my LookingUp program. Click on image to enlarge.
For a list of constellation names to go with the abbreviations click here.
Star chart annotations
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
- Leaky Big Dipper drips on Leo.
- Follow the arc of the handle of the Big Dipper to the star Arcturus and
- Continue with a spike to Spica.
- The Summer Triangle is in red.
- EAqr is the Eta Aquariid meteor shower radiant. This shower will be plagued by a waning gibbous moon. It will be addressed in the May 3rd program. This is a shower of bits from Halley’s Comet.
Twilight
Evening nautical twilight ends at 10:02 p.m. EDT on the 1st, increasing to 10:44 p.m. EDT on the 31st.
Evening astronomical twilight ends at 10:46 p.m. EDT on the 1st, increasing to 11:42 p.m. EDT on the 31st.
Morning astronomical twilight starts at 4:40 a.m. EDT on the 1st, and decreasing to 3:45 a.m. EDT on the 31st.
Morning nautical twilight starts at 5:25 a.m. EDT on the 1st, and decreasing to 4:44 a.m. EDT on the 31st.
NASA Calendar of Planetary Events
Date Time Event
May 01 Tu Venus: 27.2° E
02 We 9:24 am Venus-Aldebaran: 6.4° N
04 Fr 4:31 pm Moon-Saturn: 1.9° S
04 Fr 7:00 pm Moon South Dec.: 20.6° S
05 Sa 3:03 am Eta Aquarid Shower: ZHR = 60
05 Sa 8:35 pm Moon Apogee: 404500 km
06 Su 3:24 am Moon-Mars: 3° S
07 Mo 6:24 am Moon Descending Node
07 Mo 10:09 pm Last Quarter
08 Tu 8:10 pm Jupiter Opposition
13 Su 1:21 pm Moon-Mercury: 2.5° N
15 Tu 7:48 am New Moon
17 Th 2:11 pm Moon-Venus: 4.8° N
17 Th 5:06 pm Moon Perigee: 363800 km
18 Fr 11:02 am Moon North Dec.: 20.7° N
20 Su 7:57 am Moon-Beehive: 1.7° N
20 Su 9:13 am Moon Ascending Node
21 Mo 8:53 pm Moon-Regulus: 1.5° S
21 Mo 11:49 pm First Quarter
27 Su 1:39 pm Moon-Jupiter: 4.3° S
29 Tu 10:20 am Full Moon
31 Th 9:20 pm Moon-Saturn: 1.8° S
Jun 01 Fr Venus: 34.5° E
Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
If you go to the above site you can print out a list like the above for the entire year
or calendar pages for your time zone.
Sun and Moon Rising and Setting Events
LU Ephemeris of Sky Events for Interlochen/TC
May, 2018 Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM |
| | RISE SET HOURS | END START |PHASE SET** TIME FRACTN|
+=======================================================================+
|Tue 1| 06:32a 08:47p 14:15 | 10:00p 05:20a | Rise 10:32p 96%|
|Wed 2| 06:31a 08:49p 14:17 | 10:01p 05:18a | Rise 11:31p 91%|
|Thu 3| 06:29a 08:50p 14:20 | 10:03p 05:17a | Rise 12:26a 85%|
|Fri 4| 06:28a 08:51p 14:23 | 10:04p 05:15a | Rise 01:15a 78%|
|Sat 5| 06:27a 08:52p 14:25 | 10:06p 05:13a | Rise 02:00a 69%|
+------+-----------------------+----------------+-----------------------+
|Sun 6| 06:25a 08:53p 14:28 | 10:07p 05:12a | Rise 02:39a 60%|
|Mon 7| 06:24a 08:55p 14:30 | 10:09p 05:10a |L Qtr Rise 03:14a 51%|
|Tue 8| 06:23a 08:56p 14:33 | 10:11p 05:08a | Rise 03:45a 41%|
|Wed 9| 06:21a 08:57p 14:35 | 10:12p 05:06a | Rise 04:14a 32%|
|Thu 10| 06:20a 08:58p 14:38 | 10:14p 05:05a | Rise 04:42a 23%|
|Fri 11| 06:19a 08:59p 14:40 | 10:15p 05:03a | Rise 05:09a 15%|
|Sat 12| 06:18a 09:00p 14:42 | 10:17p 05:02a | Rise 05:38a 8%|
+------+-----------------------+----------------+-----------------------+
|Sun 13| 06:16a 09:02p 14:45 | 10:18p 05:00a | Rise 06:09a 3%|
|Mon 14| 06:15a 09:03p 14:47 | 10:20p 04:59a | Rise 06:45a 1%|
|Tue 15| 06:14a 09:04p 14:49 | 10:21p 04:57a |New Set 09:20p 1%|
|Wed 16| 06:13a 09:05p 14:52 | 10:23p 04:56a | Set 10:32p 3%|
|Thu 17| 06:12a 09:06p 14:54 | 10:24p 04:54a | Set 11:40p 9%|
|Fri 18| 06:11a 09:07p 14:56 | 10:26p 04:53a | Set 12:41a 17%|
|Sat 19| 06:10a 09:08p 14:58 | 10:27p 04:51a | Set 01:33a 26%|
+------+-----------------------+----------------+-----------------------+
|Sun 20| 06:09a 09:09p 15:00 | 10:29p 04:50a | Set 02:17a 37%|
|Mon 21| 06:08a 09:10p 15:02 | 10:30p 04:49a |F Qtr Set 02:55a 48%|
|Tue 22| 06:07a 09:12p 15:04 | 10:32p 04:47a | Set 03:27a 59%|
|Wed 23| 06:06a 09:13p 15:06 | 10:33p 04:46a | Set 03:56a 70%|
|Thu 24| 06:05a 09:14p 15:08 | 10:34p 04:45a | Set 04:24a 79%|
|Fri 25| 06:05a 09:15p 15:09 | 10:36p 04:44a | Set 04:52a 87%|
|Sat 26| 06:04a 09:16p 15:11 | 10:37p 04:43a | Set 05:20a 93%|
+------+-----------------------+----------------+-----------------------+
|Sun 27| 06:03a 09:16p 15:13 | 10:38p 04:42a | Set 05:51a 97%|
|Mon 28| 06:02a 09:17p 15:15 | 10:39p 04:41a | Set 06:24a 99%|
|Tue 29| 06:02a 09:18p 15:16 | 10:41p 04:40a |Full Rise 09:21p 100%|
|Wed 30| 06:01a 09:19p 15:18 | 10:42p 04:39a | Rise 10:18p 98%|
|Thu 31| 06:00a 09:20p 15:19 | 10:43p 04:38a | Rise 11:10p 95%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise
03/30/2018 – Ephemeris – Previewing April skies
Ephemeris for Good Friday, Friday, March 30th. The Sun will rise at 7:27. It’ll be up for 12 hours and 40 minutes, setting at 8:07. The Moon, 1 day before full, will set at 7:50 tomorrow morning.
The 4th month of the year begins on Sunday. Daylight hours in the Interlochen/Traverse City area and will increase from 12 hours and 46 minutes Sunday to 14 hours 12 minutes on April 30th. The altitude, or angle, of the Sun above the southern horizon at local noon will be 50 degrees Sunday and will ascend to 60 degrees on April 30th. The altitude of the Sun in the Straits area will be a degree lower. The actual time of local apparent noon when the sun passes due south, will be about 1:43 p.m. The Lyrid meteor shower will reach it’s peak on the early afternoon of the 22nd. So the early morning hours between 3 and 5 a.m. are the best time to see it when the Moon has set and the radiant is high in the sky.
Addendum
April Evening Sky Chart
Star Chart for April 2018 (10 p.m. EDT April 15, 2018). Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 9 p.m. EDT in the evening and 5 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian during EDT and 45 minutes behind our daylight standard time meridian. during EST). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes (Daylight Time) or 45 minutes (Standard Time) earlier than the current time.
Note the chart times of 10 p.m. and 5 a.m. are for the 15th. For each week before the 15th add ½ hour (28 minutes if you’re picky). Watch out for the time change. For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog.
April Morning Star Chart
Star Chart for April 2018 mornings based on 5 a.m. April 15th. Created using my LookingUp program. Click on image to enlarge.
For a list of constellation names to go with the abbreviations click here.
Star chart annotations
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
- Leaky Big Dipper drips on Leo.
- Follow the arc of the handle of the Big Dipper to the star Arcturus and
- Continue with a spike to Spica.
- The Summer Triangle is in red.
- LyrR is the Lyrid meteor shower radiant. The Lyrid meteor shower will reach its peak for us on the morning of the 22nd. The actual peak time is variable for this shower and can occur as early as 6 a.m. to as late as 5 p.m. Also the peak numbers of meteors are variable. Best time to observe without the Moon is between 3 a.m. and the start of twilight.
Twilight
Evening nautical twilight ends at 9:17 p.m. EDT on the 1st, increasing to 10:00 p.m. EDT on the 30th.
Evening astronomical twilight ends at 9:54 p.m. EDT on the 1st, increasing to 10:44 p.m. EDT on the 30th.
Morning astronomical twilight starts at 5:47 a.m. EDT on the 1st, and decreasing to 4:43 a.m. EDT on the 30th.
Morning nautical twilight starts at 6:23 a.m. EDT on the 1st, and decreasing to 5:27 a.m. EDT on the 30th.
NASA Calendar of Planetary Events
Date Time Event
Apr 01 Su Venus: 19.9° E
01 Su 1:47 pm Mercury Inferior Conj.
02 Mo 3:02 pm Mars-Saturn: 1.3° N
03 Tu 10:14 am Moon-Jupiter: 4.2° S
07 Sa 8:50 am Moon-Saturn: 2.1° S
07 Sa 10:37 am Moon South Dec.: 20.3° S
07 Sa 2:15 pm Moon-Mars: 3.5° S
08 Su 1:32 am Moon Apogee: 404100 km
08 Su 3:18 am Last Quarter
10 Tu 4:09 am Moon Descending Node
15 Su 9:57 pm New Moon
17 Tu 3:29 pm Moon-Venus: 5.5° N
18 We 10:35 am Uranus Conjunction
19 Th 12:45 am Moon-Aldebaran: 1.1° S
20 Fr 10:44 am Moon Perigee: 368700 km
21 Sa 3:38 am Moon North Dec.: 20.4° N
22 Su 1:49 pm Lyrid Shower: ZHR = 20
22 Su 5:46 pm First Quarter
23 Mo 2:17 am Moon-Beehive: 2° N
23 Mo 8:19 am Moon Ascending Node
24 Tu 12:47 pm Venus-Pleiades: 3.5° S
24 Tu 3:39 pm Moon-Regulus: 1.2° S
29 Su 1:59 pm Mercury Elongation: 27° W
29 Su 8:58 pm Full Moon
30 Mo 1:16 pm Moon-Jupiter: 4.1° S
May 01 Tu Venus: 27.2° E
Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
If you go to the above site you can print out a list like the above for the entire year
or calendar pages for your time zone.
Sun and Moon Rising and Setting Events
LU Ephemeris of Sky Events for Interlochen/TC
April, 2018 Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM |
| | RISE SET HOURS | END START |PHASE SET** TIME FRACTN|
+=======================================================================+
|Sun 1| 07:23a 08:10p 12:46 | 09:15p 06:19a | Rise 09:35p 97%|
|Mon 2| 07:21a 08:11p 12:49 | 09:16p 06:17a | Rise 10:40p 93%|
|Tue 3| 07:19a 08:12p 12:53 | 09:18p 06:15a | Rise 11:44p 87%|
|Wed 4| 07:18a 08:14p 12:56 | 09:19p 06:13a | Rise 12:44a 80%|
|Thu 5| 07:16a 08:15p 12:59 | 09:20p 06:11a | Rise 01:41a 71%|
|Fri 6| 07:14a 08:16p 13:02 | 09:22p 06:09a | Rise 02:33a 62%|
|Sat 7| 07:12a 08:17p 13:05 | 09:23p 06:07a | Rise 03:20a 53%|
+------+-----------------------+----------------+-----------------------+
|Sun 8| 07:10a 08:19p 13:08 | 09:25p 06:05a |L Qtr Rise 04:03a 43%|
|Mon 9| 07:09a 08:20p 13:11 | 09:26p 06:03a | Rise 04:40a 34%|
|Tue 10| 07:07a 08:21p 13:14 | 09:28p 06:01a | Rise 05:14a 25%|
|Wed 11| 07:05a 08:22p 13:17 | 09:29p 05:59a | Rise 05:45a 17%|
|Thu 12| 07:03a 08:24p 13:20 | 09:31p 05:57a | Rise 06:14a 11%|
|Fri 13| 07:01a 08:25p 13:23 | 09:32p 05:55a | Rise 06:42a 5%|
|Sat 14| 07:00a 08:26p 13:26 | 09:34p 05:53a | Rise 07:10a 2%|
+------+-----------------------+----------------+-----------------------+
|Sun 15| 06:58a 08:27p 13:29 | 09:35p 05:51a |New Set 08:05p 0%|
|Mon 16| 06:56a 08:29p 13:32 | 09:37p 05:49a | Set 09:16p 1%|
|Tue 17| 06:55a 08:30p 13:35 | 09:38p 05:47a | Set 10:27p 5%|
|Wed 18| 06:53a 08:31p 13:38 | 09:40p 05:45a | Set 11:38p 11%|
|Thu 19| 06:51a 08:32p 13:41 | 09:41p 05:43a | Set 12:47a 19%|
|Fri 20| 06:50a 08:34p 13:44 | 09:43p 05:41a | Set 01:50a 29%|
|Sat 21| 06:48a 08:35p 13:47 | 09:44p 05:39a | Set 02:46a 40%|
+------+-----------------------+----------------+-----------------------+
|Sun 22| 06:46a 08:36p 13:49 | 09:46p 05:37a |F Qtr Set 03:34a 51%|
|Mon 23| 06:45a 08:37p 13:52 | 09:47p 05:35a | Set 04:15a 62%|
|Tue 24| 06:43a 08:39p 13:55 | 09:49p 05:33a | Set 04:51a 73%|
|Wed 25| 06:41a 08:40p 13:58 | 09:50p 05:31a | Set 05:22a 82%|
|Thu 26| 06:40a 08:41p 14:01 | 09:52p 05:29a | Set 05:52a 90%|
|Fri 27| 06:38a 08:42p 14:04 | 09:53p 05:28a | Set 06:20a 95%|
|Sat 28| 06:37a 08:44p 14:06 | 09:55p 05:26a | Set 06:48a 99%|
+------+-----------------------+----------------+-----------------------+
|Sun 29| 06:35a 08:45p 14:09 | 09:57p 05:24a |Full Rise 08:25p 100%|
|Mon 30| 06:34a 08:46p 14:12 | 09:58p 05:22a | Rise 09:30p 99%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
03/29/2018 – Ephemeris – The Easter date is set by the first full moon of spring and a developing conjunction
Ephemeris for Thursday, March 29th. The Sun will rise at 7:29. It’ll be up for 12 hours and 37 minutes, setting at 8:06. The Moon, 2 days before full, will set at 7:21 tomorrow morning.
This Sunday, April 1st will be Easter for western churches. Because it falls on the first Sunday after the first full moon since March 21st. The Full Moon is Saturday the 31st. It happens that Passover begins at sundown the 31st. Orthodox churches will celebrate Easter on April 8th, a week later. It’s going to be a somewhat busy weekend in the sky also. Sunday Mercury will pass from the evening sky to the morning sky in an event called an inferior conjunction of the Sun. It is not visible, but folks in the southern hemisphere will easily spot Mercury late in April. In the morning sky Mars will pass below Saturn between the mornings of the 2nd and 3rd. They are close to the same brightness, but Mars is distinctly redder.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Conjunction animation of Mars passing Saturn at daily intervals at 6 a.m. for March 30 to April 4, 2018. This will occur above the Teapot asterism of the constellation of Sagittarius. Created using Stellarium ans GIMP.
03/01/2018 – Ephemeris – Previewing March skies
Ephemeris for Thursday, March 1st. The Sun will rise at 7:20. It’ll be up for 11 hours and 10 minutes, setting at 6:30. The Moon, at full today, will rise at 6:16 this evening.
Let’s look at the skies for the month of March. The Sun will pass the celestial equator in March as the promising season of spring will begin. Daylight hours in the Interlochen/Traverse City area and will increase from 11 hours and 10 minutes today to 12 hours 43 minutes on the 31st. The altitude, or angle, of the Sun above the southern horizon at local noon will be just under 38 degrees today and will ascend to nearly 50 degrees on the 31st. The altitude of the Sun in the Straits area will be a degree lower. Local apparent noon this month, when the Sun passes due south, will be about 12:49 p.m. and an hour later when daylight time starts. Spring will begin on the 20th at 12:15 p.m. Daylight Time, which now rules most of the year will start on the 11th.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
March Evening Sky Chart
Star Chart for March 2018 (10 p.m. EDT March 15, 2018). Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 9 p.m. EDT in the evening and 6 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian. during EDT and 45 minutes behind our daylight standard time meridian. during EST). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes (Daylight Time) or 45 minutes (Standard Time) earlier than the current time if you are near your time meridian. Note that Daylight time starts at 2 a.m. Sunday March 11th for most US states.
Note the chart times of 10 p.m. and 6 a.m. are for the 15th. For each week before the 15th add ½ hour (28 minutes if you’re picky). Watch out for the time change. For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog.
March Morning Star Chart
Star Chart for March 2018 mornings based on 6 a.m. March 15th. Created using my LookingUp program. Click on image to enlarge.
For a list of constellation names to go with the abbreviations click here.
Star chart annotations
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
- Leaky Big Dipper drips on Leo.
- Follow the arc of the handle of the Big Dipper to the star Arcturus and
- Continue with a spike to Spica.
- The Summer Triangle is in red.
Twilight
Evening nautical twilight ends at 7:32 p.m. EST on the 1st, increasing to 9:16 p.m. EDT on the 31st.
Evening astronomical twilight ends at 8:06 p.m. EST on the 1st, increasing to 9:52 p.m. EDT on the 31st.
Morning astronomical twilight starts at 5:44 a.m. EST on the 1st, and decreasing to 5:49 a.m. EDT on the 31st.
Morning nautical twilight starts at 6:17 a.m. EST on the 1st, and decreasing to 6:25 a.m. EDT on the 31st.
NASA Calendar of Planetary Events
Date Time Event
Mar 01 Th Venus: 12.4° E
01 Th 12:09 am Moon-Regulus: 0.9° S
01 Th 7:51 pm Full Moon (Worm Moon)
04 Su 8:32 am Neptune Solar Conjunction
07 We 1:57 am Moon-Jupiter: 4.4° S
09 Fr 6:20 am Last Quarter
09 Fr 7:37 pm Moon-Mars: 4.2° S
10 Sa 9:37 pm Moon-Saturn: 2.5° S
11 Su 1:39 am Moon South Dec.: 20.1° S
11 Su 2:00 am Daylight Saving Time begins
11 Su 4:13 am Moon Apogee: 404700 km
13 Tu 11:48 pm Moon Descending Node
15 Th 10:59 am Mercury Greatest Eastern Elongation: 18.4°
17 Sa 9:12 am New Moon
18 Su 3:07 pm Moon-Venus: 3.9° N
19 Mo 3:51 am Mercury-Venus: 3.8° N
20 Tu 12:15 pm Vernal Equinox
22 Th 6:33 pm Moon-Aldebaran: 0.9° S
24 Sa 11:35 am First Quarter
24 Sa 10:04 pm Moon North Dec.: 20.2° N
26 Mo 1:17 pm Moon Perigee: 369100 km
26 Mo 8:52 pm Moon-Beehive: 2.2° N
27 Tu 6:56 am Moon Ascending Node
28 We 9:38 am Moon-Regulus: 1° S
31 Sa 8:37 am Full Moon (Blue Moon)
Apr 01 Su Venus: 19.9° E
Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
If you go to the above site you can print out a list like the above for the entire year
or calendar pages for your time zone.
Sun and Moon Rising and Setting Events
LU Ephemeris of Sky Events for Interlochen/TC
March, 2018 Local time zone: EST
+-----------------------------------------------------------------------+
| DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM |
| | RISE SET HOURS | END START |PHASE SET** TIME FRACTN|
+=======================================================================+
|Thu 1| 07:20a 06:30p 11:10 | 07:33p 06:17a |Full Rise 06:16p 100%|
|Fri 2| 07:18a 06:31p 11:13 | 07:35p 06:15a | Rise 07:29p 99%|
|Sat 3| 07:16a 06:33p 11:16 | 07:36p 06:13a | Rise 08:40p 95%|
+------+-----------------------+----------------+-----------------------+
|Sun 4| 07:15a 06:34p 11:19 | 07:37p 06:12a | Rise 09:48p 89%|
|Mon 5| 07:13a 06:35p 11:22 | 07:38p 06:10a | Rise 10:53p 82%|
|Tue 6| 07:11a 06:37p 11:25 | 07:40p 06:08a | Rise 11:57p 73%|
|Wed 7| 07:09a 06:38p 11:28 | 07:41p 06:06a | Rise 12:58a 64%|
|Thu 8| 07:07a 06:39p 11:31 | 07:42p 06:05a | Rise 01:56a 55%|
|Fri 9| 07:06a 06:41p 11:35 | 07:44p 06:03a |L Qtr Rise 02:50a 45%|
|Sat 10| 07:04a 06:42p 11:38 | 07:45p 06:01a | Rise 03:40a 36%|
+------+-----------------------+----------------+-----------------------+
| EDT | Time Change | | |
|Sun 11| 08:02a 07:43p 11:41 | 08:46p 06:59a | Rise 05:25a 27%|
|Mon 12| 08:00a 07:45p 11:44 | 08:48p 06:57a | Rise 06:05a 19%|
|Tue 13| 07:58a 07:46p 11:47 | 08:49p 06:55a | Rise 06:42a 12%|
|Wed 14| 07:57a 07:47p 11:50 | 08:50p 06:54a | Rise 07:15a 7%|
|Thu 15| 07:55a 07:48p 11:53 | 08:52p 06:52a | Rise 07:45a 3%|
|Fri 16| 07:53a 07:50p 11:56 | 08:53p 06:50a | Rise 08:13a 0%|
|Sat 17| 07:51a 07:51p 12:00 | 08:54p 06:48a |New Set 08:06p 0%|
+------+-----------------------+----------------+-----------------------+
|Sun 18| 07:49a 07:52p 12:03 | 08:56p 06:46a | Set 09:13p 2%|
|Mon 19| 07:47a 07:54p 12:06 | 08:57p 06:44a | Set 10:21p 7%|
|Tue 20| 07:45a 07:55p 12:09 | 08:58p 06:42a | Set 11:30p 13%|
|Wed 21| 07:44a 07:56p 12:12 | 09:00p 06:40a | Set 12:39a 22%|
|Thu 22| 07:42a 07:57p 12:15 | 09:01p 06:38a | Set 01:48a 32%|
|Fri 23| 07:40a 07:59p 12:18 | 09:02p 06:36a | Set 02:53a 43%|
|Sat 24| 07:38a 08:00p 12:21 | 09:04p 06:34a |F Qtr Set 03:54a 54%|
+------+-----------------------+----------------+-----------------------+
|Sun 25| 07:36a 08:01p 12:25 | 09:05p 06:32a | Set 04:47a 65%|
|Mon 26| 07:34a 08:02p 12:28 | 09:06p 06:30a | Set 05:34a 76%|
|Tue 27| 07:32a 08:04p 12:31 | 09:08p 06:28a | Set 06:14a 85%|
|Wed 28| 07:31a 08:05p 12:34 | 09:09p 06:26a | Set 06:49a 92%|
|Thu 29| 07:29a 08:06p 12:37 | 09:11p 06:25a | Set 07:21a 97%|
|Fri 30| 07:27a 08:07p 12:40 | 09:12p 06:23a | Set 07:50a 100%|
|Sat 31| 07:25a 08:09p 12:43 | 09:13p 06:21a |Full Rise 08:27p 100%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise
01/05/2017 – Ephemeris – About Ephemeris rise and set times, an annual confession
Thursday, January 5th. The Sun will rise at 8:19. It’ll be up for 8 hours and 58 minutes, setting at 5:17. The Moon, at first quarter today, will set at 1:23 tomorrow morning.
Lets talk about the Ephemeris program itself. The format has changed little in the 41 ½ years it’s been on the air. The problem with talking about rising and setting phenomenon is that back when I started IPR has only one transmitter and that was next to the studio Now it has transmitters covering just about all of the northwestern part of the Lower Peninsula of Michigan. So your rise and set time can be quite different. On my Ephemeris website I have the times listed for the year for several locations in the IPR listening area under calendars. On any search engine search for Bob Moler Ephemeris. The Ephemeris Blog ( you’re already here) contains transcripts of the programs with illustrations and more in depth explanations.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Bob Moler’s Ephemeris main web page. http://ephemeris.bjmoler.org.
The red arrow points to the calendars for some locations, The green arrows point to program mp3s for the current week. The blue arrows point to links to this blog.
Calendars currently available:
Cadillac
Interlochen/Traverse City (Source for the times on the Ephemeris program)
Ludington
Mackinaw City
Petoskey
Eagle Harbor – Keweenaw Peninsula
Houghton Lake
Earth’s Equator at the Prime Meridian (Just for fun. See how the daylight hours stay pretty much at 12 hours)
12/31/2016 – Ephemeris year end
No radio program today, being the weekend, so at the end of the calendar page below are the stats for today, the 31st. This is the form of the calendar that I have on my Ephemeris website, which I update monthly. It was created with the same data that the first portion of my program is generated from. I have yearly calendars for 6 communities in the Interlochen Public Radio area in northwestern lower Michigan, and 1 in the U.P. (That’s the Upper Peninsula, if you’re not from around here.)
You will have to hold off your New Years festivities for a bit tonight. Not long, just one second. Today, December 31st, 2016 will be 24 hours and 1 second long. This “leap second” will be added as the 61st second of the minute 6:59 p.m. EST (23:59 UT). The reason is that the Earth’s rotation is slowing down ever so slightly, compared to the atomic clocks at the Bureau of Time. There is some discussion of eliminating this leap second. Most scientists want to use a constant time stream, and don’t give a hang about the rotation of the Earth. The positions of the Earth, Moon and the other planets would be incorrect if we used time strictly based on the Earth’s rotation. Atomic time which is also affected by special and general relativity is used by GPS navigation satellites. A one second jump in time, at our latitude (45° north) is equivalent of the earth’s rotation of about two tenths of a mile. I hope everyone’s coordinated on this.
Ephemeris of Sky Events for Interlochen/TC |
||||||||||
| December, 2016 – Local time zone: EST | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Date | Sun | Twilight* | Moon | Illum | ||||||
| Rise | Set | Hours | End | Start | Phase | R/S** | Time | Fractn | ||
| Thu | 1 | 08:00a | 05:03p | 09:03 | 06:48p | 06:15a | Set | 07:10p | 6% | |
| Fri | 2 | 08:01a | 05:03p | 09:01 | 06:47p | 06:16a | Set | 08:02p | 11% | |
| Sat | 3 | 08:02a | 05:02p | 09:00 | 06:47p | 06:17a | Set | 08:59p | 18% | |
| Sun | 4 | 08:03a | 05:02p | 08:58 | 06:47p | 06:18a | Set | 09:59p | 26% | |
| Mon | 5 | 08:04a | 05:02p | 08:57 | 06:47p | 06:19a | Set | 11:02p | 36% | |
| Tue | 6 | 08:05a | 05:02p | 08:56 | 06:47p | 06:20a | Set | 12:08a | 46% | |
| Wed | 7 | 08:06a | 05:02p | 08:55 | 06:47p | 06:21a | F Qtr | Set | 01:16a | 57% |
| Thu | 8 | 08:07a | 05:02p | 08:54 | 06:47p | 06:22a | Set | 02:26a | 68% | |
| Fri | 9 | 08:08a | 05:02p | 08:53 | 06:47p | 06:22a | Set | 03:39a | 78% | |
| Sat | 10 | 08:09a | 05:02p | 08:52 | 06:47p | 06:23a | Set | 04:53a | 87% | |
| Sun | 11 | 08:10a | 05:02p | 08:51 | 06:48p | 06:24a | Set | 06:08a | 94% | |
| Mon | 12 | 08:11a | 05:02p | 08:51 | 06:48p | 06:25a | Set | 07:21a | 98% | |
| Tue | 13 | 08:12a | 05:02p | 08:50 | 06:48p | 06:26a | Full | Rise | 05:18p | 100% |
| Wed | 14 | 08:12a | 05:02p | 08:49 | 06:48p | 06:26a | Rise | 06:17p | 98% | |
| Thu | 15 | 08:13a | 05:02p | 08:49 | 06:49p | 06:27a | Rise | 07:21p | 94% | |
| Fri | 16 | 08:14a | 05:03p | 08:48 | 06:49p | 06:28a | Rise | 08:28p | 88% | |
| Sat | 17 | 08:14a | 05:03p | 08:48 | 06:49p | 06:28a | Rise | 09:35p | 80% | |
| Sun | 18 | 08:15a | 05:03p | 08:48 | 06:50p | 06:29a | Rise | 10:41p | 70% | |
| Mon | 19 | 08:16a | 05:04p | 08:48 | 06:50p | 06:29a | Rise | 11:44p | 61% | |
| Tue | 20 | 08:16a | 05:04p | 08:48 | 06:51p | 06:30a | L Qtr | Rise | 12:46a | 51% |
| Wed | 21 | 08:17a | 05:05p | 08:48 | 06:51p | 06:30a | Rise | 01:46a | 41% | |
| Thu | 22 | 08:17a | 05:05p | 08:48 | 06:52p | 06:31a | Rise | 02:45a | 32% | |
| Fri | 23 | 08:18a | 05:06p | 08:48 | 06:52p | 06:31a | Rise | 03:43a | 24% | |
| Sat | 24 | 08:18a | 05:07p | 08:48 | 06:53p | 06:32a | Rise | 04:40a | 16% | |
| Sun | 25 | 08:18a | 05:07p | 08:48 | 06:53p | 06:32a | Rise | 05:37a | 10% | |
| Mon | 26 | 08:19a | 05:08p | 08:49 | 06:54p | 06:32a | Rise | 06:33a | 5% | |
| Tue | 27 | 08:19a | 05:09p | 08:49 | 06:55p | 06:33a | Rise | 07:26a | 2% | |
| Wed | 28 | 08:19a | 05:09p | 08:50 | 06:55p | 06:33a | Rise | 08:16a | 0% | |
| Thu | 29 | 08:19a | 05:10p | 08:50 | 06:56p | 06:33a | New | Set | 05:57p | 1% |
| Fri | 30 | 08:19a | 05:11p | 08:51 | 06:57p | 06:34a | Set | 06:53p | 3% | |
| Sat | 31 | 08:20a | 05:12p | 08:52 | 06:58p | 06:34a | Set | 07:52p | 7% | |
| * Astronomical Twilight | ||||||||||
| ** Moonrise or moonset, whichever occurs between sunset and sunrise | ||||||||||
The far right column of the table, the Moon’s illuminated fraction, may or may not appear in the calendar above depending on you browser or screen size. It is correct on the Ephemeris website.
05/31/2016 – Ephemeris – Previewing June’s bright skies
Ephemeris for Tuesday, May 31st. Today the Sun will be up for 15 hours and 20 minutes, setting at 9:20, and it will rise tomorrow at 6:00. The Moon, 2 days past last quarter, will rise at 3:55 tomorrow morning.
Tomorrow will be the first of June, so let’s preview June skies. There will be a lot of sunlight in June. The daylight hours will increase a bit from 15 hours and 21 minutes tomorrow to 15 hours and 34 minutes on the 20th, the solstice, retreating back to 15 hours 31 minutes at month’s end. At this time of the year the sunset times for Ludington, Interlochen, Petoskey and Mackinaw City are very nearly the same.* However the sunrise times are at their most divergent. With Ludington’s sunrise being 14 minutes later than Mackinaw City’s. The altitude of the sun above the southern horizon at local noon will increase from about 67 and a half degrees to 68 and three-quarters on the 20th. Local noon, when the sun is actually due south will occur at about 1:43 p.m.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
* See http://ephemeris.bjmoler.org/calendar.htm
Addendum
June Star Chart
Star Chart for June 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 11 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 10:45 p.m. EDT on the 1st, increasing to 10:57 p.m. EDT on the 30th.
Morning nautical twilight starts at 4:36 a.m. EDT on the 1st, and decreasing to 4:35 a.m. EDT on the 30th.
Add a half hour to the chart time every week before the 15th and subtract a half hour for every week after the 15th. Before the 13th also subtract an hour for Standard Time.
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
- A leaky Big Dipper drips on Leo
- Follow the arc of the handle of the Big Dipper to the star Arcturus
- Extend the arc to a spike to point to Spica.
- 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. Some additions made to aid clarity.
Date Time Event Jun 01 We Venus: 1.5° W 03 Fr 1:43 a.m. Saturn Opposition 03 Fr 5:47 a.m. Moon-Mercury: 0.7° N 03 Fr 6:55 a.m. Moon Perigee: 361100 km 04 Sa 11:00 p.m. New Moon 05 Su 4:59 a.m. Mercury Greatest Elongation: 24.2° W 06 Mo 5:13 a.m. Moon North Dec.: 18.6° N 06 Mo 5:34 p.m. Venus Superior Conjunction with the Sun. 10 Fr 10:47 a.m. Moon-Regulus: 2.2° N 11 Sa 3:35 p.m. Moon-Jupiter: 1.6° N 11 Sa 6:20 p.m. Moon Ascending Node 12 Su 4:10 a.m. First Quarter 13 Mo 6:06 a.m. Mercury-Pleiades: 6.8° S 15 We 8:00 a.m. Moon Apogee: 405000 km 18 Sa 8:40 p.m. Moon-Saturn: 3.6° S 18 Sa 11:39 p.m. Mercury-Aldebaran: 3.8° N 20 Mo 7:02 p.m. Full Moon 20 Mo 2:52 p.m. Moon South Dec.: 18.6° S 20 Mo 6:35 p.m. Summer Solstice 26 Su 1:28 a.m. Moon Descending Node 27 Mo 2:19 p.m. Last Quarter Jul 01 Venus: 6.8° E
03/25/2016 – Ephemeris – Easter, the reason for our calendar
Ephemeris for Good Friday, Friday, March 25th. The Sun will rise at 7:35. It’ll be up for 12 hours and 26 minutes, setting at 8:02. The Moon, 2 days past full, will rise at 10:17 this evening.
The so-called movable feasts of the church calendar are based on the date Easter falls on. They span from Ash Wednesday to Pentecost. And Easter is determined by astronomical events. In 1582 the fact that the actual vernal equinox had fallen 10 days behind the Julian calendar then in use which was decreed by Julius Caesar in 45 BC. Pope Gregory XIII in the 1580’s resolved to fix the situation and commissioned some astronomers to work on the problem. The solution was to fix the 10 day problem by eliminating the days October 5th through 14th of the October 1582 calendar and modifying the leap year rule to keep February 29th in calendars whose years were evenly divisible by 4, except those century years not also divisible by 400. Thus the year 2000 was a leap year, but 1900 and 2100 was and will not be.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Gregorian Calendar in essence decoupled Easter from Passover by keeping the formula first Sunday after the first full moon after March 21st, as a marker for the vernal equinox, and keeping March 21st on or near the vernal equinox. Passover this year starts sunset on April 22nd, while Orthodox Easter will occur on May 1st. The reason is the relationship between the Jewish lunar calendar and the Julian Calendar I mentioned in yesterday’s post. The difference between the Julian and Gregorian Calendars is now 13 days.
The error in the Gregorian calendar is at most 1 day in 3,300 years, in relation to the seasonal year. But the Gregorian Calendar makes calculating the date of Easter more complicated. It introduces something called Epact to the list of chronological cycles in an almanac. The quantity called Epact is the age of the moon on January 1st, and still has a relationship with the Metonic Cycle and the Golden Number which I discussed yesterday. This year the value is 21.
As I’ve admitted before, the first paragraph of these posts are generated by a computer program. Part of that program is a list of holidays, and those designated as movable feasts use the date of Easter as a starting point. I use the 10 step method from Astronomical Algorithms by Jean Meeus. Easter for the Julian Calendar is a simpler 6 step method.
Bob Moler's Ephemeris Blog 