Archive
05/28/2012 – Ephemeris – Memorials in the solar system
Ephemeris for Memorial Day, Monday, May 28th. Today the sun will be up for 15 hours and 14 minutes, setting at 9:17. The moon, at first quarter today, will set at 2:10 tomorrow morning. Tomorrow the sun will rise at 6:01.
Memorial day is a day of remembrance for those who paid the ultimate price for our freedom. When astronomers name craters or other features on planets or moons, they are names of those who have gone before. For instance craters near the moon’s north and south poles are named for explorers of the corresponding earthly pole. The Challenger astronauts have craters named for them in the moon system of Uranus, from discovery pictures relayed to the earth by Voyager 2 a few days before the Challenger accident. The Mars Rover Spirit is itself a silent sentinel in the Columbia Hills on Mars, its features named for the Columbia astronauts who died 11 months before Spirit landed.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/18/11 – Ephemeris – Dawn orbits Vesta
Monday, July 18th. Today the sun will be up for 15 hours and 8 minutes, setting at 9:22. The moon, 3 days past full, will rise at 10:49 this evening. Tomorrow the sun will rise at 6:15.
Two days ago the Dawn spacecraft dropped into orbit of the asteroid Vesta. After nearly four years, most of it thrusting its ion engine, Dawn slipped into orbit of this 320 mile diameter asteroid. It will spend the next year photographing, and scanning the chemical composition of this second largest and brightest of the asteroids. It will slowly spiral closer to Vesta for a closer look. Also the change in velocity of the spacecraft as it orbits Vesta will give clues to the asteroid’s internal structure. Also to be closely monitored will be the large crater near Vesta’s south pole. An impact here less than a billion years ago spread debris throughout the inner solar system. Many of the meteorites on the earth have been traced to Vesta.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/12/11 – Ephemeris – Dim prospects for the James Webb Space Telescope
Tuesday, July 12th. Today the sun will be up for 15 hours and 18 minutes, setting at 9:27. The moon, 3 days before full, will set at 4:24 tomorrow morning. Tomorrow the sun will rise at 6:09.
The US House Appropriation Committee is planning to cancel the Jame Webb Space Telescope. This follow on to the wildly successful Hubble Space Telescope, is, like its predecessor over budget and behind schedule. The Webb will gather over 6 times the light as the Hubble, and operate in the infrared where the action is in astronomy now a days. As it is currently funded the Webb telescope might not be launched by 2018. They are cutting NASA’s budget by 1.6 billion dollars and want to mandate instead the development of a heavy lift rocket, for which there is no immediate use. As it is the commercial SpaceX company supposedly can upgrade their current Falcon 9 rocket to a Falcon Heavy quicker and cheaper than NASA can produce their heavy rocket.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Artist's view of the James Webb Space Tellescope. Courtesy NASA.
Artist's conception of the Falcon Heavy rocket. Courtesy SpaceX.
06/14/11 – Ephemeris – Fate of the Apollo lunar flags
Flag Day, Tuesday, June 14th. Today the sun will be up for 15 hours and 32 minutes, setting at 9:28. The moon, 1 day before full, will set at 5:35 tomorrow morning. Tomorrow the sun will rise at 5:56
Whatever happened to the flags left on the moon by the Apollo astronauts? Forty or so years after the landings the sun’s harsh unfiltered light, especially in the ultraviolet has bleached and degraded the nylon fabric of the flags. Also the lunar soil, called regolith contains small jagged particles that are very compact and hard to pound a flag pole in. Apparently the flags of all but Apollo 11 and 15 are still standing, while the rocket blast of the lunar module ascent stage blew down the other two. The flag of the United States is carried on two spacecraft that are about to leave the magnetic bubble around the sun that is the heliosphere. The farthest, Voyager 1 is 117 times the earth’s distance from the sun, nearly 11 billion miles away.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
05/17/11 – Ephemeris – The Dawn spacecraft sights its target the asteroid Vesta
Tuesday, May 17th. Today the sun will be up for 14 hours and 52 minutes, setting at 9:05. The moon, at full today, will rise at 9:51 this evening. Tomorrow the sun will rise at 6:11.
The Dawn spacecraft is about to make news. Never heard of it? Well, it’s been slowly building up speed for the last nearly four years, spiraling its way out into the asteroid belt with its ion engines and one gravity assist from the red planet Mars, on which it tested its cameras. Its first target is coming up, the asteroid Vesta, the brightest of asteroids, though not the largest. There won’t be a time of engine firing to drop the spacecraft into orbit, but Dawn will slowly spiral into lower and lower orbits of this asteroid starting in July. It will spend a year at Vesta before heading to the largest asteroid, now dubbed dwarf planet Ceres. Last week dawn took its first image of Vesta, which covered 5 pixels in its camera, and shows Dawn to be right on target.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
05/16/11 – Ephemeris – Space Shuttle Endeavour to launch this morning
Monday, May 16th. Today the sun will be up for 14 hours and 50 minutes, setting at 9:04. The moon, 1 day before full, will set at 6:01 tomorrow morning. Tomorrow the sun will rise at 6:12
If all goes well the Space Shuttle Endeavor will lift off for the International Space Station at 8:56 this morning (EDT). The Endeavour, named for the for British Captain James Cook’s first vessel, which was sailed to Tahiti in in 1769 to observe the transit of Venus across the sun as part of an effort to determine the earth’s distance from the sun. Endeavour’s 25th and last flight will be the second to last flight of the Shuttle program. Gregory Johnson, mission pilot has family and a cottage in the area. The State Theater in downtown Traverse City will be open for a live feed of the launch starting at 8 a.m. if the launch is still a go. It will be hosted by NASA Solar System Ambassador Carolyn McKellar. This is a free event.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Update
There were over 200 people, young and old that came to the theater for the event. It was very successful for such short notice of a relatively few days. Great work Carolyn and the volunteers and staff of the State Theater!
MESSENGER’s in orbit of Mercury!
Just like clockwork! I’m looking for a year of new discoveries about this nearest planet to the sun.
They’re tweeting at http://www.twitter.com/messenger2011.
MESSENGER’s web site is at http://messenger.jhuapl.edu/.
NASA’s MESSENGER page is at http://www.nasa.gov/mission_pages/messenger/main/.
03/17/11 – Ephemeris – MESSENGER spacecraft arrives at Mercury tonight
Ephemeris for St. Patrick’s Day, Thursday, March 17th. The sun will rise at 7:51. It’ll be up for 11 hours and 59 minutes, setting at 7:50. The moon, 2 days before full, will set at 6:48 tomorrow morning.
This evening the MESSENGER Spacecraft will fire its main engine for 15 minutes to put itself in orbit of the planet Mercury. The rocket firing will be at 8:45 this evening. Due to light time delays caused by Mercury being 97 million miles away, we won’t know if the rocket fired until 8:54. While its high gain antenna won’t be pointed at earth, we should get a signal from its omni- directional antenna. We did get a signal from Cassini with its orbital insertion of Saturn in 2004, and that was nearly a billion miles away. I don’t know if NASA TV’s covering the insertion live, but Johns Hopkins Applied Physics Laboratory is having a live webcast. Google “messenger mercury live orbital insertion” It was the first hit. I’ll have the address on the blog. http://messenger.jhuapl.edu/mer_orbit.html
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Phil Plait has a great video of the STS133 Launch
From Phil Plait’s Bad Astronomy blog comes a great Video taken from several cameras on the solid rocket boosters (SRBs). The greatest sight for me was to see from the aft cameras the shuttle orbiter and the fuel tank depart after the SRB’s were jettisoned. Here’s a screen cap from the left aft SRB camera. Check out the entire video. There’s only one or two launches left.
STS133 orbiter and fuel tank leaving the booster behind
Image credit NASA.
01/27/11 – Ephemeris – Mars at superior conjunction
Thursday, January 27th. The sun will rise at 8:06. It’ll be up for 9 hours and 37 minutes, setting at 5:44. The moon, 1 day past last quarter, will rise at 3:46 tomorrow morning.
Starting today the planet Mars will be too close to the direction of the sun to send commands from the earth to Opportunity rover and satellites orbiting it.. The sun is noisy in the radio spectrum. This is seen in the spring and fall when geosynchronous satellite signals are lost when the satellite passes in front of the sun. This blackout isn’t total. The Mars Odyssey orbiter will be receiving data from te rover daily and relaying it back to the earth but at a very slow bit rate. The disruption of communications will last two weeks centered on February 4th when Mars will seem pass two sun diameters south of the sun. In reality it will be 129 million miles behind the sun. and 221 million miles from the earth.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Bob Moler's Ephemeris Blog 