Archive
05/06/2014 – Ephemeris – A square crater on the moon
Ephemeris for Tuesday, May 6th. The sun rises at 6:25. It’ll be up for 14 hours and 27 minutes, setting at 8:53. The moon, at first quarter today, will set at 2:40 tomorrow morning.
Tonight’s moon reveals some great features. Back in my early astronomy days, one of the odd thing I saw on the moon with my telescope at about this phase, was what appeared as a square crater on the moon. Craters are supposed to be round. This one was near the north pole of the moon. It can be seen with a small telescope. It was given the name Barrow. I’ve since confirmed that it is indeed quite square, with a small crater, Barrow A sitting on one corner. The Lunar Reconnaissance Orbiter shows this in great detail. Also on the north end of the moon tonight is the Alpine Valley, which looks like a gash crossing the Lunar Alps. Lunar mountain ranges tend to be named for earthly mountains, but are really crater walls.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
First quarter Moon at 10 p.m. May 6, 2014. Created using Virtual Moon Atlas.
The square crater Barrow and the Alpine Valley as it would be seen in a telescope on May 6, 2014 at 10 p.m. Created using Virtual Moon Atlas.
The Barrow crater as imaged by the Lunar Reconnaissance Orbiter. Credit NASA/GSFC/Arizona State University, Virtual Moon Atlas.
Actually Barrow almost looks pentagonal in the above image.
The Alpine Valley as imaged by the Lunar Reconnaissance Orbiter. Credit NASA/GSFC/Arizona State University, Virtual Moon Atlas.
05/05/2014 – Ephemeris – LADEE is no more but its mission goes on
Ephemeris for Monday, May 5th. The sun rises at 6:27. It’ll be up for 14 hours and 24 minutes, setting at 8:52. The moon, 1 day before first quarter, will set at 2:09 tomorrow morning.
The Lunar Atmosphere and Dust Environment Explorer or LADEE spacecraft that was in a close orbit of the moon to sniff out the Moon’s tenuous exosphere of gases and dust, augured into the moon’s far side April 17th as planned. This was just the end of the data acquisition phase of the mission. The data will be pored over for years to develop a picture of the lunar environment. This will aid lunar explorers to come both robotic and human. Something similar is happening to the Kepler mission to find transiting planets of other stars. The data gathering phase is over but there was an announcement a week or such ago of an earth sized planet in a stars habitable zone. Discoveries will go on for years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Artist’s depiction of LADEE in orbit of the Moon. Courtesy NASA.
More about the LADEE Mission is here.
05/01/2014 – Ephemeris – Previewing May skies
Ephemeris for Thursday, May 1st. The sun rises at 6:32. It’ll be up for 14 hours and 14 minutes, setting at 8:47. The moon, 2 days past new, will set at 11:21 this evening.
Today we will start the month when the promise of spring is finally fulfilled, we hope. Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 14 minutes today to 15 hours 18 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 Aquarid meteor shower will reach its peak about 2 a.m. this Sunday morning the 4th. I’ll have more on my blog bobmoler.wordpress.com today.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
The Eta Aquarid Meteor Shower
This shower is associated with Halley’s Comet. We see two meteor showers from Halley’s comet. One in October where the comet debris is crossing the earth’s orbit heading toward the sun, and again as its leaving. This shower is caused by the debris leaving the vicinity of the sun.
The Eta Aquarid radiant at the peak of the shower. The radiant moves slowly to the east with time. Credit: Bob Moler’s LookingUp program.
The peak of the shower will be at 7 h UT on May 6th. That’s 3 a.m. EDT, about 20 minutes before the radiant will rise. This will give about one hour before astronomical twilight starts to view the meteor shower in completely dark skies.
Possible Meteor Storm – May 24
There will be the possibility of a meteor storm on the morning of May 24th. A meteor storm differs from a meteor shower in the numbers of meteors seen and duration. There is a possibility of up to 400 meteors per hour for the hours of 7h to 8h UT (3 to 4 a.m. EDT).
The body responsible is Comet 209P/LINEAR. It was the 209th periodic comet discovered on February 3, 2004 by Lincoln Near-Earth Asteroid Research (LINEAR). Despite the recent discovery 209P has been orbiting the sun for hundreds of years, maybe longer. This year the comet will come close to the Earth and will allow the Earth to pass through debris that it shed hundreds of years ago.
Comet 209P/LINEAR crosses the Earth’s orbit around May 28, 2014. The “stilts” on the comet’s orbit show that it is coming from north of the Earth’s orbital plane. Credit: Bob Moler’s LookingUp program.
The radiant for the Comet 209P/LINEAR debris. For this purpose I’ve designated it Camelopardids (not official and probably not correct). Credit: Bob Moler’s LookingUp program. Note that the constellation of Camelopardalis is a giraffe.
Astronomical Twilight starts at 3:51 a.m., but the skies should remain dark enough. The 24% illuminated moon will rise about 2:45 or so and may not be much of an impediment in seeing the meteor storm.
May Star Chart
Star Chart for mid-month for May 2014 at 11 p.m. Credit: Bob Moler’s LookingUp program.
Add a half hour to every week before the 15th and subtract and hour for every week after the 15th.
For a list of constellation names to go with the abbreviations click here.
Bob Moler's Ephemeris Blog 