Archive
05/08/2018 – Ephemeris – Jupiter at opposition
Ephemeris for Tuesday, May 8th. The Sun rises at 6:23. It’ll be up for 14 hours and 33 minutes, setting at 8:56. The Moon, 1 day past last quarter, will rise at 3:45 tomorrow morning.
At 8:10 p.m. Jupiter will be in opposition, that is opposite the Sun in the sky. Thursday at 8 a.m. it will be its closest to the Earth at 408.9 million miles away, and its biggest in telescopes at 44.8 arc seconds. The Moon averages about 1,800 arc seconds in diameter. So the Moon appears 40 times larger in diameter, meaning you could put 40 Jupiters across the diameter of the moon. Jupiter’s disk is visible in binoculars, along with several of its moons. The moons change position from night to night. Most computer planetarium programs will show the moons for any time past and future. Telescopes will reveal that Jupiter’s face is crossed by bands of contrasting colors of clouds, and the famous Great Red Spot.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter with its Great Red Spot November 18, 2012 by Scott Anttila.
05/07/2018 – Ephemeris – Twilight
Note: Sorry for the delay. I was hit with a fast developing cold Sunday. So I was unable to post this at my normal time, and was unable to record my next Tuesday through Monday programs.
Ephemeris for Monday, May 7th. The Sun rises at 6:24. It’ll be up for 14 hours and 30 minutes, setting at 8:55. The Moon, at last quarter today, will rise at 3:14 tomorrow morning.
We are in the time of year when it appears that twilight doesn’t seem to end. There are three definitions of twilight, Civil, Nautical and Astronomical. Each ends in the evening when the Sun is 6, 12, and 18 degrees below the horizon respectively. Astronomers don’t really care about civil twilight, the sky is too bright. Sailors using a sextant for star positions can usually see the horizon for star sighting up to the end of nautical twilight. Astronomers consider the skies dark at the end of astronomical twilight, barring he Moon being up. The brightest stars and planets become visible a half hour after sunset. We begin to pick out constellations at the end of nautical twilight. For instance, for tonight, nautical twilight ends at 10:10 p.m., while astronomical twilight ends at 10:57.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
05/04/2018 – Ephemeris – Tonight I present Venus from the mists of time to today
Ephemeris for Friday, May 4th. The Sun rises at 6:28. It’ll be up for 14 hours and 23 minutes, setting at 8:51. The Moon, 3 days before last quarter, will rise at 1:15 tomorrow morning.
The planet Venus is our evening star now. I’ve been talking about it on this program lately. Want to hear and see more? Tonight at 8 p.m. at the May meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers Observatory, I will be giving an illustrated talk: Venus from the mists of time to today. To the early Greeks it was two planets. To the Maya it was a calendar. In the 18th century it was a way to measure the size of the solar system. Today, it could be what our future looks like. After the meeting, at 9 p.m. the society will host a star party to view the planets Venus and Jupiter. The observatory is located south of Traverse City on Birmley Road between Garfield and Keystone roads.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
5 Pages of the Dresden Codex produced by the Maya tracking Venus’ appearances in the skies over the Yucatan. for 104 years. The Dresden Codex is one of only 4 surviving Mayan Codices.
05/03/2018 – Ephemeris – The Eta Aquariid meteor shower is coming
Ephemeris for Thursday, May 3rd. The Sun rises at 6:29. It’ll be up for 14 hours and 20 minutes, setting at 8:50. The Moon, half way from full to last quarter, will rise at 12:26 tomorrow morning.
Saturday morning at about 3 a.m. is the predicted peak of the Eta Aquariid Meteor Shower. The bright Moon will interfere with all but the brightest, however something interesting is afoot. I download the International Meteor Organization Meteor Calendar every year. An Internet search for the name will get you to it. It seems that the Maya had recorded the shower’s appearance along with other meteor showers. There are other peaks to this shower on the mornings possibly through the 6th. Meteors of this shower, are caused by particles released by Halley’s Comet on past swings through the inner solar system. The meteors will appear to come from low in the southeastern sky. They will be seen after 3:30 a.m.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Eta Aquariid radiant at the peak of the shower. The radiant moves slowly to the east with time. Credit: Bob Moler’s LookingUp program.
We get two meteor showers from Halley’s Comet. The Orionids, when Halley is approaching the inner solar system, and the Eta Aquariids when it’s leaving. Credit my LookingUp program.
05/02/2018 – Ephemeris – We’re taking our weekly look at the bright planets
Ephemeris for Wednesday, May 2nd. The Sun rises at 6:31. It’ll be up for 14 hours and 17 minutes, setting at 8:49. The Moon, 3 days past full, will rise at 11:31 this evening.
It’s Wednesday again and time to look for the bright planets. One bright planet is in the evening sky, the brightest, Venus. It will be visible low in the western twilight from about 9:10 p.m. until it sets at 11:15. The star Aldebaran will be seen below and left of Venus tonight. Jupiter will rise this evening at 9:11 p.m. That doesn’t make it an evening planet. It has to rise before sunset to be an evening planet, which it will be next Wednesday. Saturn will rise at 1:09 a.m., while Mars will rise at 2:18 a.m.
At 5:30 tomorrow morning these three planets will be strung across the southern sky. Bright Jupiter will be in the southwest, dimmer Mars and Saturn will be in the south, with Mars to the left of Saturn with the Moon between Jupiter and Saturn.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus in evening twilight at 9:15 p.m, tonight May 2, 2018. Click on the image to enlarge. Created using Stellarium.
The morning planets at 5:30 a.m. May 3, 2018. Click on the image to enlarge. Created using Stellarium.
The waning gibbous Moon at 5:30 a.m. May 3, 2018. Created using Stellarium.
The morning planets as seen in a telescope using the same magnification at 5:30 a.m. May 3, 2018. A magnified image of Mars is inset showing some of the features that may be visible under higher magnification. Created using Cartes du Ciel (Sky Charts).
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on May 2, 2018. The night ends on the left with sunrise on the 3rd. Click on the image to enlarge. Created using my LookingUp program.
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
04/30/2018 – Ephemeris – Venus-Earth resonances, and Jupiter & the Moon tonight
Ephemeris for Monday, April 30th. The Sun rises at 6:34. It’ll be up for 14 hours and 12 minutes, setting at 8:46. The Moon, 1 day past full, will rise at 9:30 this evening.
Jupiter will be near the moon tonight. The gravitational force between the planets produces some interesting resonances in their orbital periods. Venus has three different kinds with the Earth. First, Venus orbits the Sun 13 times in the same time it takes the Earth to orbit the Sun 8 times. This is a 13 to 8 resonance. This sets up the 5 Venus Cycles equaling 8 years resonance the Mayan’s discovered. A Venus cycle of 584 days takes Venus to go from Morning Star to Evening Star and back again. The next one wasn’t discovered until we started to bounce radar signals off Venus. We found it rotates backwards, and very slowly at that. Its rotation with respect to the stars is longer than its year. And it so happens that every passage near the Earth the same side of Venus is facing us.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon and Jupiter at 10 p.m. tonight, April 30, 2018. Created using Stellarium.
04/27/2018 – Ephemeris – The Mayan special relationship to Venus
Ephemeris for Arbor Day, Friday, April 27th. The Sun rises at 6:38. It’ll be up for 14 hours and 4 minutes, setting at 8:42. The Moon, 2 days before full, will set at 6:20 tomorrow morning.
The Mayans of Mesoamerica a thousand years ago diligently observed Venus and discovered Venus’ unique cycles that they used to correct their calendars. The first was the Venus Cycle, the period we’d say that Venus passes between the Earth and the Sun to enter the morning sky to the next time it does it. That was 584 days. Its appearance in the morning sky would last 263 days, Then it would disappear near the Sun, actually behind it for 50 days. It would reappear in the evening sky for another 263 days before again disappearing near the Sun, this time for only 8 days. These are the 4 phases of a Venus cycle. Five of these cycles equals almost exactly 8 years, called a sequence. 13 sequences equal 104 years, a Venus Round.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus Cycle derived from John P Pratt who has another purpose for the diagram and annotated by me to include the number of days in each phase. For my purposes ignore points 1 and 4. The Mayan cycle starts with 7, the first appearance of Venus during the morning. Points 8 and 5 are the points where Venus is at greatest elongation from the Sun. Credit John P Pratt.
04/26/2018 – Ephemeris – When the Greeks thought Venus was two separate planets
Ephemeris for Thursday, April 26th. The Sun rises at 6:40. It’ll be up for 14 hours and 1 minute, setting at 8:41. The Moon, 3 days before full, will set at 5:52 tomorrow morning.
For the next three programs I’m going to take a look at Venus through the eyes of the ancient, or pre-telescopic cultures. It’s a teaser for the program I’m presenting at the NMC Observatory May 4th. Venus from the mists of time to today. We call Venus’ appearance in the morning the Morning Star and its evening appearance, the Evening Star. The very ancient Greeks thought they were two separate planets. The morning planet was Phosphorus, and the evening planet was Hesperus. Somewhere around the 4th or 3rd century BC someone figured the when Hesperus was out in the evening Phosphorus was not out the next morning, and vice versa. The then single planet was named Aphrodite, by whose Roman name, Venus, we still call it by today.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus (Hesperus) at its evening eastern greatest elongation on August 18, 2018 showing the part of its orbit that’s above the horizon. Created using Stellarium and GIMP.
Venus (Phosphorus) at its morning western greatest elongation on January 6, 2019 showing the part of its orbit that’s above the horizon. Jupiter is the other planet visible. Created using Stellarium and GIMP.
Venus at inferior conjunction on October 27, 2018 showing its entire orbit on a smaller scale than the images above from the Earth’s perspective. The far part of the orbit goes behind the Sun. The planets Mercury and Jupiter are seen left of the Sun. Created using Stellarium.
04/25/2018 – Ephemeris – It’s bright planet Wednesday
Ephemeris for Wednesday, April 25th. The Sun rises at 6:41. It’ll be up for 13 hours and 58 minutes, setting at 8:40. The Moon, 3 days past first quarter, will set at 5:22 tomorrow morning.
It’s Wednesday again and time to look for the bright planets. One bright planet is in the evening sky, the brightest, Venus. It will be visible low in the western twilight from about 9:10 p.m. until it sets at 10:58. Venus is blindingly bright in binoculars or a small telescope. Jupiter will rise this evening at 9:42 p.m. That doesn’t make it an evening planet. It has to rise before sunset to be an evening planet. Give it a couple of weeks. Saturn will rise at 1:37 a.m., while Mars will rise at 2:33 a.m.
At 6 tomorrow morning these three planets will be strung across the southern sky. Bright Jupiter will be in the southwest, dimmer Mars and Saturn will be in the south, with Mars to the left of Saturn in the morning twilight.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location
Addendum
Venus in evening twilight at 9 p.m, tonight April 25, 2018. Created using Stellarium.
The Gibbous Moon tonight at 10 p.m., April 25, 2018. Created using Stellarium.
The morning planets at 6 a.m. April 26, 2018. Click on the image to enlarge. Created using Stellarium.
The morning planets as seen in a telescope using the same magnification. A magnified image of Mars is inset showing some of the features that may be visible under higher magnification. Created using Cartes du Ciel (Sky Charts).
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on April 25, 2018. The night ends on the left with sunrise on the 26th. Click on the image to enlarge. Created using my LookingUp program.
