Archive
04/29/2016 – Ephemeris – Let’s preview the merry skies of May
Ephemeris for Arbor Day, Friday, April 29th. The Sun rises at 6:34. It’ll be up for 14 hours and 10 minutes, setting at 8:45. The Moon, at last quarter today, will rise at 3:01 tomorrow morning.
Sunday starts the month when the promise of spring is finally fulfilled. Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 16 minutes Sunday to 15 hours 20 minutes on the 31st. The altitude, or angle, of the Sun above the southern horizon at local noon will ascend from 60 degrees Sunday 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 daylight will be a few minutes longer. The big event of May will be the transit of the tiny planet Mercury across the face of the Sun on May 9th. I’ll have more on that next week. Also Mars will be in opposition from the Sun on the 22nd which due to its elliptical orbit will actually be closest to us 8 days later on the 30th at 46.779 million miles (75.284 million km).
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
May Star Chart
Star Chart for May 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.
Evening nautical twilight ends at 10:00 p.m. EDT on the 1st, increasing to 10:43 p.m. EDT on the 31st.
Morning nautical twilight starts at 5:20 a.m. EDT on the 1st, and decreasing to 4:38 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. 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 ac to a spike to point to Spica
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
May 01 Su Venus: 9.8° W
02 Mo 9:27 p.m. Moon Descending Node
04 We 2:45 p.m. Eta Aquarid Shower: ZHR = 60
06 Fr 12:14 a.m. Moon Perigee: 357800 km
06 Fr 3:30 p.m. New Moon
08 Su 4:21 a.m. Moon-Aldebaran: 0.5° S
09 Mo 7:12 a.m. Mercury transit begins
09 Mo 10:57 a.m. Mercury mid-transit
09 Mo 2:42 p.m. Mercury transit ends
09 Mo 5:54 p.m. Moon North Dec.: 18.4° N
13 Fr 1:02 p.m. First Quarter
14 Sa 3:06 a.m. Moon-Regulus: 2.5° N
15 Su 5:30 a.m. Moon-Jupiter: 2.2° N
15 Su 4:39 p.m. Moon Ascending Node
18 We 6:06 p.m. Moon Apogee: 405900 km
21 Sa 5:15 p.m. Full Moon
22 Su 7:15 a.m. Mars Opposition
22 Su 5:59 a.m. Moon-Saturn: 3.5° S
24 Tu 7:16 a.m. Moon South Dec.: 18.5° S
29 Su 8:12 a.m. Last Quarter
30 Mo 12:45 a.m. Moon Descending Node
30 Mo 5:36 p.m. Mars closest to the Earth 0.50321 AU
Jun 01 We Venus: 1.5° W
Transit of Mercury
May 9, 2016 7:12 a.m. (11:21 UT) to 2:42 p.m. (18:42 UT)
The track of Mercury across the face of the Sun. Mercury will travel from upper left to lower right. Mercury will not be visible until it impinges upon the disk of the Sun. Credit IOTA’s program Occult4.
The map showing where the transit is visible in whole or in part. If using Firefox enlarge the map by right clicking on it and select View Image.
02/20/2015 – Ephemeris – The Moon joins Venus and Mars in the west tonight
Ephemeris for Friday, February 20th. The sun will rise at 7:35. It’ll be up for 10 hours and 42 minutes, setting at 6:17. The moon, 2 days past new, will set at 8:49 this evening.
Tonight the two day old moon will be seen in the west in a tight triangle with Venus and Mars. They will become visible about 7 o’clock. The planets will be to the left of the Moon with much dimmer Mars above Venus. The formation is tight enough that the motion of the moon will be evident between 7 and when the Moon sets at 8:49. The moon moves its own diameter in about an hour. The moon will also exhibit earthshine, the reflection of the bright earth in the moon’s sky on the night side of the Moon itself. The earthshine lit part of the moon shows a ghostly man in the moon image we are familiar with at full moon. This earthshine is visible on the Moon for a few days before new moon to a few days after new moon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Views of the Venus, Mars, Moon grouping from three locations.
Appearance of the grouping from northern Michigan, US
Venus and Mars with the Moon at 7 p.m. EST on February 20, 2015. This is for northern Michigan. Created using Stellarium.
Appearance of the grouping from Los Angeles, CA
Venus and Mars with the Moon at 8 p.m. PST on February 20, 2015. This is for Los Angeles, CA. Created using Stellarium.
Appearance of the grouping from London, UK
Venus and Mars with the Moon at 20:28 GMT on February 20, 2015. This is for London, UK. Created using Stellarium.
10/16/2014 – Ephemeris – Comet Siding Spring will buzz Mars this Sunday
Ephemeris for Thursday, October 16th. The sun will rise at 7:59. It’ll be up for 10 hours and 57 minutes, setting at 6:56. The moon, 1 day past last quarter, will rise at 1:50 tomorrow morning.
Sunday afternoon our time the comet C/2013 A1 also known a Siding Spring will pass 86 thousand miles (140 thousand km) from Mars. The three NASA Mars satellites, Mars Odyssey, Mars Reconnaissance Orbiter and Maven plus the two rovers Opportunity and Curiosity; the European Mars Express and the latest to arrive, India’s Mars Orbital Mission or MOM will all be studying the comet. Protection of the satellites is key. The satellite’s orbits have all been phased so as to be behind the planet from the expected possible debris of the comet when Mars passes its closest to the comet’s orbit 101 minutes after the comet itself passes. Early next week we may have some spectacular photos of Comet Siding Spring.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Two views of Comet Siding Springs orbit past Mars. Credit: NASA.
Planned science observations of Comet Siding Spring by NASA spacecraft and rovers at Mars. Credit: NASA.
Siding Spring Links:
09/29/2014 – Ephemeris – The Moon, Mars and Antares will line up tonight
Ephemeris for Monday, September 29th. The sun will rise at 7:37. It’ll be up for 11 hours and 48 minutes, setting at 7:26. The moon, 2 days before first quarter, will set at 10:49 this evening.
Tonight we’ll still have Mars hanging around the star Antares. However we’ll have the Moon joining the party. The three will nearly be in line at 9 p.m. with the fat crescent Moon on top, Mars below it and Antares below Mars. They will be in a straighter line but the Sun out makes them impossible to see. With binoculars or a small telescope the lunar seas visible, kind of in order from the Moon’s sunlit edge are Crises, Fertility, Nectar, Tranquility and half of Serenity. If you’re looking for the Man in the Moon, you’ll have to wait until the Moon is nearly full to completely discern his face. However most of the upside down rabbit is visible. The seas of Fertility and Nectar make up his ears, Tranquility, his head, and Serenity his body.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon, Mars and the bright red star Antares line up on the evening of September 29, 2014. Created using Stellarium.
The moon tonight September 29, 2014. Created using Virtual Moon Atlas.
09/23/2014 – Ephemeris – NASA’s MAVEN satellite is in orbit of Mars
Ephemeris for Tuesday, September 23rd. The sun will rise at 7:30. It’ll be up for 12 hours and 7 minutes, setting at 7:37. The moon, 1 day before new, will rise at 7:53 tomorrow morning.
Last Sunday evening the MAVEN spacecraft fired its six main engines in alternating pairs for 33 minutes and was captured by Mars, entering orbit around the Red Planet. MAVEN is one of those NASA acronyms, it stands for Mars Atmospheric and Volatile EvolutioN Once in a capture orbit, the orbit will be changed from a 33 hour orbit to a 4 ½ hour a science orbit. It will investigate how Mars lost its original atmosphere which was dense enough to support liquid water to the thin carbon dioxide atmosphere it has today. It has several duties October 19th when Comet Siding Spring passes Mars to detect the interaction of the comet’s atmosphere with that of Mars. There are no cameras* on Maven, just hard data will be returned.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
* Actually I was mistaken. There is an Imaging Ultraviolet Spectrograph aboard which will take images in the ultraviolet of Mars upper atmosphere.
Artist’s rendition of the MAVEN spacecraft in Mars Orbit. Credit: Lockheed Martin/NASA.
04/08/2014 – Ephemeris – Mars is at opposition today!
Ephemeris for Tuesday, April 8th. The sun will rise at 7:10. It’ll be up for 13 hours and 7 minutes, setting at 8:18. The Moon, 1 day past first quarter, will set at 4:10 tomorrow morning.
Mars is at opposition from the Sun today. That doesn’t mean that Mars and the Sun are opposed to each other. Well, I guess they are, sort of. It really means that the Sun and Mars are opposite one another in the sky with Mars rising at sunset, staying up all night and setting at sunrise. That puts the earth smack dab between the Sun and Mars. For most planets this is the time of closest approach. Mars, however, has a markedly elliptical orbit, and in its orbit, it is moving closer to the sun, so it will actually come a bit closer to the Earth this go around on April 14th, next Monday when it will be 372,000 miles closer. That’s not much out of 57 million miles. Still Mars is a tiny planet in telescopes.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars’ closest approaches with the earth 2003 to 2018. Created with my LookingUp program.
Mars through a telescope tonight (April 8, 2014). Apparent diameter 15.1″. Created using Stellarium.
Mars at its closest approach in 50,000 or so years on August 27, 2003. Apparent diameter 25.1″. Created using Stellarium.
Apparent diameters are in seconds or arc. One second of arc is 1/3600th of a degree. or about 1/1800th of the width of the Moon or Sun.
03/28/2014 – Ephemeris – Mars approaches
Ephemeris for Friday, March 28th. The sun will rise at 7:30. It’ll be up for 12 hours and 34 minutes, setting at 8:04. The moon, 2 days before new, will rise at 6:40 tomorrow morning.
The planet Mars is making its every 26 month on average close approach to the Earth. Mars will reach opposition from the sun on April 8th, rising at sunset and setting at sunrise. Due to Mars’ strongly elliptical orbit, it will actually be closest to us 6 days later on April 14th. That distance will be about 57.4 million miles, nearly twice that if its closest distance of 34.6 million miles it came back in 2003. But take heart, the opposition distances are closing. On July 31, 2018 it will again be below 36 million miles away. Even at its closest, Mars is a tiny object for the telescope. It’s half the size of the Earth and at its closest will appear less that half the size that Jupiter appears to us.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars’ closest approaches with the earth 2003 to 2018. Created with my LookingUp program.
02/25/2014 – Ephemeris – Mars starts its retrograde motion this weekend
Ephemeris for Tuesday, February 25th. The sun will rise at 7:26. It’ll be up for 10 hours and 58 minutes, setting at 6:24. The moon, 3 days past last quarter, will rise at 5:15 tomorrow morning.
The planet Mars, which rises about 10:30 p.m. and is near the star Spica, is slowing its eastward motion as the Earth approaches it. Mars will stop and appear to reverse course on Saturday March 1st. It will begin what astronomers call retrograde motion. This westward motion will continue past Mars’ opposition with the sun on April 8th, and its closest approach to the Earth on April 14th. Mars retrograde motion will end on May 21st when Mars will resume its prograde or eastward motion. The ancient Greeks especially had a problem with this because they believed that celestial bodies traveled in uniform circular motion. They added a circle on the planet’s main circle called an epicycle to kind of solve the problem. The problem was solved centuries later by Copernicus who made the earth another planet and Kepler who made the planet orbits elliptical.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The trails of Mars and three asteroids from December 2013 to August 2014. Created using Stellarium.
Vesta and Ceres are going retrograde at the same time as Mars. The Dawn spacecraft traveling between Vesta to Ceres is about half way in between them. The other trail, not exhibiting retrograde is that of the small asteroid 2012 DA14 whose claim to fame is that it passed inside the ring of geosynchronous satellites on February 15, 2013. It was completely upstaged a few hours earlier by the meteor that exploded over Chelyabinsk, Russia. It looks like the orbital trail shown for 2012 DA14 has not been updated. As the result of the encounter with Earth that day the asteroid’s orbit was altered. 2012 DA14 is a provisional designation based on the year, half month and order of discovery. It’s permanent designation with a name is 367943 Duende. The name of the asteroid is usually up to the discoverer with the approval of the International Astronomical Union (IAU). It is the 367,943rd asteroid whose orbital elements are known. BTW Ceres is 1 Ceres, and Vesta is 4 Vesta. Though the 4th asteroid found, Vesta is the brightest, at the very limit of naked eye visibility.
10/08/2013 – Ephemeris – Comet ISON spotted from Mars
Ephemeris for Tuesday, October 8th. The sun will rise at 7:49. It’ll be up for 11 hours and 20 minutes, setting at 7:09. The moon, 3 days before first quarter, will set at 9:36 this evening.
Tonight look in the southwest at 8 p.m. or so to see the crescent moon to the upper left of Venus. In other news last week Sunday the Mars Reconnaissance Orbiter took photographs of Comet ISON. These have been posted on the Internet. Google ISON Mars. The Satellite’s HiRISE camera wasn’t built for the task, and only revealed a faint blob of light. Earth bound amateur astronomers can do a lot better. The images are posted on the University of Arizona’s web site and are not affected by government shutdown. Any images of the comet from the Curiosity rover will have to wait until the shutdown is over to be posted. Operators of the Opportunity and Curiosity rovers are still at work since ongoing space operations are deemed essential.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
HiRISE images of Comet ISON on Sept. 29, 2013. Credit: NASA/JPL/University of Arizona.
08/27/2013 -Ephemeris – It’s August 27th. Do you know where Mars is?
Ephemeris for Tuesday, August 27th. The sun will rise at 6:59. It’ll be up for 13 hours and 28 minutes, setting at 8:27. The moon, 1 day before last quarter, will rise at 12:01 tomorrow morning.
It’s August 27th. Do you know where Mars is? The Mars hoax is back. It’s been 10 years since it was first sent out on the Internet as an email. You know the one that says Mars will appear as big as the Moon? In order to appear as big as the Moon Mars would have to be only a half million miles away. Mars in its orbit can never come closer than 34.6 million miles from earth. It came that close to the earth on August 27th, 2003. Even then it was a tiny orb in telescopes. That’s why we have to send spacecraft, taking many months to reach it to get a close look at it. Right now Mars is 214.9 million miles away, over twice the distance of the sun. It is seen in the east in the early morning below the much brighter Jupiter.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars and Earth relative positions for August 27, 2013. Orbits are to scale, however object sizes are greatly exaggerated. Created using my LookingUp program.
Bob Moler's Ephemeris Blog 