Archive
06/08/2017 – Ephemeris – The late heavy bombardment of the inner planets
Ephemeris for Thursday, June 8th. Today the Sun will be up for 15 hours and 28 minutes, setting at 9:25, and it will rise tomorrow at 5:57. The Moon, 1 day before full, will set at 6:22 tomorrow morning.
The Moon and many bodies of the inner solar system have many craters which bear witness to many meteorite hits. In studying lunar samples brought back by the Apollo astronauts, from Russian lunar sample return missions and meteorites found on Earth that came from the Moon planetary scientists found that many of their ages correspond to a narrow range of dates of 3.8 to 4.1 billion years ago. Radioisotope dating of rocks would date them to the last time they were molten. This lead to the hypothesis that about a half billion years after the planets were formed, the inner solar system bodies were pelted with millions of asteroids in what is known as the late heavy bombardment. The reason is not completely understood, but one hypothesis is that the outer planets migrated destabilizing the asteroid belt causing the solar system to be a shooting gallery.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Lunar seas and their ages. Credit NASA.
How the migration of the outer planets caused the Late Heavy Bombardment. Credit James Green, Director Planetary Science, NASA.
06/07/2017 – Ephemeris – It’s Wednesday and time to look at this week’s planets
Ephemeris for Wednesday, June 7th. Today the Sun will be up for 15 hours and 27 minutes, setting at 9:25, and it will rise tomorrow at 5:57. The Moon, 2 days before full, will set at 5:44 tomorrow morning.
Let’s take our weekly look at the bright planets. I’m no longer going to cover Mars until it’s back in the morning sky next year. It’s too dim in twilight t really spot. Though next year July it will be closer to us than it’s been since 2003. Dominating the evening sky now besides the Moon is Jupiter in the south-southwest. The bright blue-white star Spica is seen left and below it. In even the smallest telescopes Jupiter’s four largest moons can be seen. They shift positions night from to night and sometimes even as you watch. Jupiter will set at 3:13 a.m. Saturn can now be seen late in the evening after it rises in the east-southeast at 9:46 p.m. At 5 a.m. both Saturn and Venus will be in the morning twilight. Brilliant Venus will be low in the east tomorrow morning after rising at 3:33 a.m.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter and the Moon in twilight at 10:30 p.m., June 7, 2017. Created using Stellarium.
Jupiter and its four Galilean moons as they might be seen in a telescope at 10:30 p.m,. June 7, 2017. Created using Cartes du Ciel (Sky Charts).
The moon as seen in binoculars, tonight at 10:30 p.m., June 7, 2017. Created using Stellarium.
Venus, Saturn and the setting Moon at 5 a.m. June 8, 2017. Created using Stellarium. Click on the image to expand.
Saturn and its brightest moons overnight June 7/8, 2017. Created using Cartes du Ciel (Sky Charts).
Venus as it might be seen through a telescope at 5 a.m. June 8, 2017. This is displayed at a larger scale/magnification than the Jupiter or Saturn images above. Created using Stellarium.
Planets at sunset and sunrise of a single night starting with sunset on the right on June 7, 2017. The night ends on the left with sunrise on June 8. Click on the image to enlarge. Created using my LookingUp program.
06/06/2017 – Ephemeris – Where did the Moon come from?
Ephemeris for Tuesday, June 6th. Today the Sun will be up for 15 hours and 26 minutes, setting at 9:24, and it will rise tomorrow at 5:57. The Moon, 3 days before full, will set at 5:10 tomorrow morning.
The origin of the Moon is a question that has vexed astronomers for years. Did it break off the molten Earth like a cell dividing? Was it captured by passing too close to the Earth? Neither is satisfactory. Chemical elements have different isotopes depending on the number of neutrons in their nucleus. The rocks brought back by the Apollo astronauts show that the isotopes of the elements in the rocks is that same as for the Earth. We know that Mars and the asteroids have different isotope ratios. The hypothesis that seems most likely is that another planet, the size of Mars collided with the 100 million year old Earth in a glancing blow that gave rise to a disk of material that eventually coalesced into the Moon.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The hypothetical collision of a Mars sized body with the young Earth. Credit: Joe Tucciarone via NASA
06/05/2017 – Ephemeris – Why Venus is low in the eastern sky
Ephemeris for Monday, June 5th. Today the Sun will be up for 15 hours and 25 minutes, setting at 9:23, and it will rise tomorrow at 5:58. The Moon, half way from first quarter to full, will set at 4:40 tomorrow morning.
Saturday the planet Venus was at greatest western elongation from the Sun, That is it is the farthest west it will appear from the Sun. It’s still not very high in our sky. However for those in the southern hemisphere Venus will appear very high in the east. There is a rule about this: Planets which are east of the Sun, like Mars is now are easiest seen on spring evenings. Planets which are west of the Sun, like Venus is now are easiest seen on autumn mornings. Since the southern hemisphere has the opposite seasons as the north, this is their autumn, and morning planets are easiest seen. This is especially true for Mercury, which is even closer to the Sun than Venus. Generally it’s only seen when it appears on spring evenings and autumn mornings.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus’ low morning appearance is due to the fact that on spring mornings the ecliptic (red line path of the Sun in the sky and nearly that of the planets) lies low to the horizon. Created using Stellarium.
06/02/2017 – Ephemeris – Local astronomy events this weekend
Ephemeris for Friday, June 2nd. Today the Sun will be up for 15 hours and 21 minutes, setting at 9:21, and it will rise tomorrow at 5:59. The Moon, 1 day past first quarter, will set at 3:17 tomorrow morning.
This weekend there are two local astronomical events.
The first is tonight at 8 p.m. at the June meeting of the Grand Traverse Astronomical Society at the Northwestern Michigan College’s Rogers Observatory. I will be giving an illustrated talk about the Moon, its phases, tides and origin. After which there will be a star party starting at 9 p.m. The observatory is located south of Traverse City on Birmley Road.
Saturday, the society will have their telescopes at the Betsie Valley District Library in Thompsonville. I’ll also give a twilight talk there at 9 p.m. on the Moon with observation to follow. This last event will be postponed if the weather is completely cloudy to Friday, June 16th.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
06/01/2017 – Ephemeris – A look ahead at the month of June
Ephemeris for Thursday, June 1st. Today the Sun will be up for 15 hours and 20 minutes, setting at 9:20, and it will rise tomorrow at 5:59. The Moon, at first quarter today, will set at 2:49 tomorrow morning.
This is the 42nd anniversary of this program as we start our 43rd orbit of the Sun. Let’s take a look at June skies. There will be a lot of Sun this month. The daylight hours will increase a bit from 15 hours and 20 minutes today to 15 hours and 33 minutes on the 21st, retreating back to 15 hours 30 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 on the solstice, June 21st will be 68 and three-quarters degrees in Interlochen. Summer will start at 12:25 a.m.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
June Evening Star Chart
Star Chart for June 2017 (11 p.m. June 15, 2017). 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 if you are near your time meridian.
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. For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog.
June Morning Star Chart
Star Chart for June 2017 mornings based on 4:30 a.m. June 15th. Created using my LookingUp program. Click on image to enlarge.
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
- Leaky Big Dipper drips on Leo
- Follow the arc of the handle of the Big Dipper to the star Arcturus,
- Then follow the Spike to Spica
- The Summer Triangle is in red
Evening nautical twilight ends at 10:47 p.m. EDT on the 1st, increasing to 11:00 p.m. EDT on the 30th.
Evening astronomical twilight ends at 11:46 p.m. EDT on the 1st, increasing to 12:03 a.m. EDT on the 30th.
Morning astronomical twilight starts at 3:42 a.m. EDT on the 1st, and changing to 3:37 a.m. EDT on the 30th.
Morning nautical twilight starts at 4:41 a.m. EDT on the 1st, and changing to 4:40 a.m. EDT on the 30th.
NASA Calendar of Planetary Events
Date Time Event
Jun 01 Th Venus: 45.8° W
01 Th 8:42 am First Quarter
03 Sa 6:59 am Venus Greatest Western Elongation: 45.9°
03 Sa 7:57 am Moon-Jupiter: 2.5° S
06 Tu 11:19 pm Mercury-Pleiades: 5.5° S
08 Th 6:21 pm Moon Apogee: 406400 km
09 Fr 9:10 am Full Moon
09 Fr 9:25 pm Moon-Saturn: 3.4° S
10 Sa 11:36 pm Moon South Dec.: 19.4° S
14 We 10:40 pm Moon Descending Node
15 Th 5:15 am Saturn Opposition
17 Sa 7:33 am Last Quarter
20 Tu 5:13 pm Moon-Venus: 2.4° N
21 We 12:25 am Summer Solstice
21 We 9:55 am Mercury Superior Conjunction with the Sun
22 Th 10:23 am Moon-Aldebaran: 0.5° S
23 Fr 6:49 am Moon Perigee: 357900 km
23 Fr 10:31 am New Moon
24 Sa 7:12 am Moon North Dec.: 19.4° N
26 Mo 7:18 am Moon-Beehive: 3.2° N
27 Tu 12:26 pm Moon Ascending Node
27 Tu 8:26 pm Moon-Regulus: 0.1° N
30 Fr 8:51 pm First Quarter
Jul 01 Sa Venus: 43.7° W
June 2017 Calendar
LU Ephemeris of Sky Events for Interlochen/TC June, 2017 Local time zone: EDT +-----------------------------------------------------------------------+ | DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM | | | RISE SET HOURS | END START |PHASE SET** TIME FRACTN| +=======================================================================+ |Thu 1| 06:00a 09:21p 15:21 | 10:44p 04:37a |F Qtr Set 02:49a 55%| |Fri 2| 05:59a 09:22p 15:22 | 10:46p 04:36a | Set 03:18a 65%| |Sat 3| 05:59a 09:23p 15:23 | 10:47p 04:35a | Set 03:45a 74%| +------+-----------------------+----------------+-----------------------+ |Sun 4| 05:58a 09:23p 15:25 | 10:48p 04:34a | Set 04:12a 82%| |Mon 5| 05:58a 09:24p 15:26 | 10:49p 04:34a | Set 04:40a 89%| |Tue 6| 05:58a 09:25p 15:27 | 10:50p 04:33a | Set 05:10a 94%| |Wed 7| 05:57a 09:26p 15:28 | 10:50p 04:33a | Set 05:44a 98%| |Thu 8| 05:57a 09:26p 15:29 | 10:51p 04:32a | Set 06:22a 100%| |Fri 9| 05:57a 09:27p 15:30 | 10:52p 04:32a |Full Rise 09:26p 100%| |Sat 10| 05:57a 09:27p 15:30 | 10:53p 04:31a | Rise 10:17p 98%| +------+-----------------------+----------------+-----------------------+ |Sun 11| 05:56a 09:28p 15:31 | 10:54p 04:31a | Rise 11:03p 95%| |Mon 12| 05:56a 09:28p 15:32 | 10:54p 04:31a | Rise 11:45p 89%| |Tue 13| 05:56a 09:29p 15:32 | 10:55p 04:30a | Rise 12:23a 83%| |Wed 14| 05:56a 09:29p 15:33 | 10:55p 04:30a | Rise 12:57a 75%| |Thu 15| 05:56a 09:30p 15:33 | 10:56p 04:30a | Rise 01:29a 65%| |Fri 16| 05:56a 09:30p 15:34 | 10:56p 04:30a | Rise 01:59a 55%| |Sat 17| 05:56a 09:31p 15:34 | 10:57p 04:30a |L Qtr Rise 02:29a 44%| +------+-----------------------+----------------+-----------------------+ |Sun 18| 05:56a 09:31p 15:34 | 10:57p 04:30a | Rise 03:00a 34%| |Mon 19| 05:56a 09:31p 15:34 | 10:57p 04:30a | Rise 03:33a 23%| |Tue 20| 05:57a 09:31p 15:34 | 10:58p 04:30a | Rise 04:11a 14%| |Wed 21| 05:57a 09:32p 15:34 | 10:58p 04:30a | Rise 04:54a 7%| |Thu 22| 05:57a 09:32p 15:34 | 10:58p 04:31a | Rise 05:45a 2%| |Fri 23| 05:57a 09:32p 15:34 | 10:58p 04:31a |New Set 09:01p 0%| |Sat 24| 05:58a 09:32p 15:34 | 10:58p 04:31a | Set 10:03p 1%| +------+-----------------------+----------------+-----------------------+ |Sun 25| 05:58a 09:32p 15:34 | 10:58p 04:32a | Set 10:56p 5%| |Mon 26| 05:58a 09:32p 15:33 | 10:58p 04:32a | Set 11:41p 12%| |Tue 27| 05:59a 09:32p 15:33 | 10:58p 04:33a | Set 12:18a 20%| |Wed 28| 05:59a 09:32p 15:32 | 10:58p 04:33a | Set 12:51a 29%| |Thu 29| 06:00a 09:32p 15:32 | 10:57p 04:34a | Set 01:21a 39%| |Fri 30| 06:00a 09:32p 15:31 | 10:57p 04:35a |F Qtr Set 01:49a 50%| +-----------------------------------------------------------------------+ * Nautical Twilight ** Moonrise or moonset, whichever occurs between sunset and sunrise
05/31/2017 – Ephemeris – Wednesday is bright planets day on Ephemeris
Ephemeris for Wednesday, May 31st. Today the Sun will be up for 15 hours and 19 minutes, setting at 9:19, and it will rise tomorrow at 6:00. The Moon, 1 day before first quarter, will set at 2:19 tomorrow morning.
Let’s take our weekly look at the bright planets. Mars is still in the west-northwest after sunset and fading. It appears left of the bottom edge of the constellation Auriga. It will set at 10:43 p.m. Dominating the evening sky now is Jupiter in the south. The bright blue-white star Spica is seen below and left of it. In even the smallest telescopes Jupiter’s four largest moons can be seen. They shift positions night from to night and sometimes even as you watch. Jupiter will set at 4:09 a.m. Saturn can now be seen late in the evening after it rises in the east-southeast at 10:15 p.m. At 5 a.m. both Saturn and Venus will be in the morning twilight. Brilliant Venus will be low in the east tomorrow morning after rising at 4:05 a.m.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars, Jupiter and the Moon in twilight at 10 p.m., May 31, 2017. Created using Stellarium. Click on the image to enlarge.
Jupiter and its four Galilean moons as they might be seen in a telescope at 10 p.m,. May 31, 2017. Created using Cartes du Ciel (Sky Charts).
The moon as seen in binoculars, tonight at 10 p.m., May 31, 2017. Created using Stellarium.
At 11 p.m., May 31, 2017 Saturn can be seen low in the southeast. Created using Stellarium.
Saturn and its brightest moons overnight May 31/June 1, 2017. Created using Cartes du Ciel (Sky Charts).
Venus and Saturn at 5 a.m. June 1, 2017. Created using Stellarium. Click on the image to expand.
Venus as seen through a telescope at 5 a.m. June 1, 2017. This is displayed at a larger scale/magnification than the Jupiter or Saturn images above. Created using Stellarium.
Planets at sunset and sunrise of a single night starting with sunset on the right on May 31, 2017. The night ends on the left with sunrise on June 1. Click on the image to enlarge. Created using my LookingUp program.
05/30/2017 – Ephemeris – Amateur astronomer detects an impact on Jupiter
Ephemeris for Tuesday, May 30th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:19, and it will rise tomorrow at 6:00. The Moon, 2 days before first quarter, will set at 1:44 tomorrow morning.
Last Friday several amateur astronomers photographing Jupiter with video CCDs captured a flash in the high northern latitude of Jupiter. Part of the reason for videos is to stack the individual images to average out the turbulence of the atmosphere they were looking through. It’s a fantastic technique. The flash was probably due to the impact of an asteroid. The first objects to have been seen to crash into Jupiter were the chunks of Comet Shoemaker-Levy 9 that crashed into Jupiter over a one week period in July of 1994. Since then several flashes have been seen, all of them captured and confirmed by amateur astronomers. Amateurs have also discovered storms on Saturn for the Cassini spacecraft to study.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter Impact alert Image annotated. Note the white spot at the top of Jupiter. Credit Sauveer Pendranghelu, Afa, Corsica, France via Damian Peach’s tweet. Click on image to enlarge.
05/29/2017 – Ephemeris – We remember too those who died reaching for the stars
Ephemeris for Memorial Day, Monday, May 29th. Today the Sun will be up for 15 hours and 16 minutes, setting at 9:18, and it will rise tomorrow at 6:01. The Moon, 3 days before first quarter, will set at 1:04 tomorrow morning.
Today we pause to remember those who gave their lives for our country. For purposes of this program that includes those courageous enough to sit on top of or beside a million pounds of explosives to be launched into space. From the three astronauts who died in the Apollo one file in 1967, the explosion of the Space Shuttle Challenger in 1986, to the disintegration of the Columbia in 2003, 17 Americans and other nationals have died in NASA space accidents. The Russians too have lost cosmonauts in the exploration of space. Brothers and sisters in the quest for knowledge and to expand the horizons of human habitation. Per aspera, ad astra, Through difficulties to the stars!
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A listing of Astronaut and Cosmonaut deaths: http://www.aerospaceweb.org/question/history/q0114.shtml
05/26/2017 – Ephemeris – Can you spot the extremely young Moon tonight?
Ephemeris for Friday, May 26th. Today the Sun will be up for 15 hours and 11 minutes, setting at 9:15, and it will rise tomorrow at 6:03. The Moon, 1 day past new, will set at 10:16 this evening.
It’s spring and a great time to see if you can spot the young moon. The official time when the moon was new was 3:44 p.m. yesterday afternoon (19:44 UT 25 May 2017), which would make the moon a bit less than 31 hours old if spotted before it sets an hour after the Sun. This requires crystal clear skies and a very low northwestern horizon. Binoculars are a definite help. Spotting the earliest moon after new moon is one of the challenges amateur astronomers pit their observing skills with. Another is the Messier Marathon, in which one tries to observe all 110 of Charles Messier’s catalog entries of dim objects on a single night, which is theoretically possible around March 24th.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A 39 hour old Moon with Jupiter taken by Greg Hogan on September 2, 2016.
I got this from EarthSky.org. Here’s a search I made of the young moon that has some other images: http://earthsky.org/?s=young+moon
