Archive
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.
07/15/11 – Ephemeris – Inland Seas Summer Festival
Friday, July 15th. Today the sun will be up for 15 hours and 13 minutes, setting at 9:25. The moon, at full today, will rise at 9:32 this evening. Tomorrow the sun will rise at 6:12.
The Grand Traverse Astronomical Society will be part of the Inland Seas Summer Festival tomorrow in Suttons Bay. If it’s clear we’ll be viewing the sun. We’ll also have exhibits including meteorites and hands on activities. July is a big month for the society with Friday Night Live appearances on the 22nd and 29th. That last week of July will also see society members at Black Star Farms, The Lanphier Observatory in Glen Arbor and at the Sleeping Bear Dunes National Lakeshore. As far as viewing the sun goes, our telescopes are equipped with safe filters that fit over the front of our telescopes and provide a safe viewing experience. Plus this year the sun is coming alive with sunspots as a new sunspot cycle is starting. It should reach peak in 2013.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/14/11 – Ephemeris – Jupiter’s two new moons.
Thursday, July 14th. Today the sun will be up for 15 hours and 15 minutes, setting at 9:25. The moon, 1 day before full, will set at 6:37 tomorrow morning. Tomorrow the sun will rise at 6:11.
Jupiter has retained its title as the planet with the most satellites with the discovery last year of two new moons. These tiny moons are just a couple of miles in size. They were reported last year but were brought to my attention by a blog entry by Kelly Beatty of Sky and Telescope magazine, who spotted it among last year’s issues of the Central Bureau for Astronomical Telegrams. They’re no longer telegrams but emails,but the name hasn’t changed. Anyway he notes back in the day the announcement of a new satellite was a big deal, But now the announcement of Jupiter’s 64th and 65th moon is no big deal. If you’re keeping count Saturn’s moon count is 62, three behind Jupiter, and we still haven’t found them all.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/13/11 – Ephemeris – The bright planets visible this week
Wednesday, July 13th. Today the sun will be up for 15 hours and 16 minutes, setting at 9:26. The moon, 2 days before full, will set at 5:29 tomorrow morning. Tomorrow the sun will rise at 6:10.
It’s Wednesday and time again to take a look at the whereabouts of the bright planets. The ringed planet Saturn will be visible in the west southwest as it gets dark. It’s near the bright star Spica to its left. Spica has a blue tinge, while Saturn is yellowish. It will set at 12:55 a.m. Saturn is a wonderful sight is a telescope with its rings. The shadows of the rings on the planet and planet on the rings are now near their maximum extent. We are now slowly seeing Saturn slip into evening twilight. We have about another month of good viewing of Saturn before its image deteriorates by being too low in the sky. Jupiter will rise at 1:40 a.m. in the east. Mars will rise at 3:33 in the east northeast.
* 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.
07/11/11 – Ephemeris – The moon’s Oceanus Procellarum
Monday, July 11th. Today the sun will be up for 15 hours and 19 minutes, setting at 9:27. The moon, 3 days past first quarter, will set at 3:25 tomorrow morning. Tomorrow the sun will rise at 6:08.
The moon tonight is a big fat gibbous phase. The terminator, now before full moon is the sunrise line that creates tonight’s phase. It’s crossing the large sea called Oceanus Procellarum or the Ocean of Storms. It is the moon’s largest sea, though really a lava basin. This is easily seen with the unaided eye and binoculars. The moon has never had oceans or seas of water. That impression was in the eyes of early telescopic observers of the moon , who even thought there was life on the moon. Oceanus is huge, by lunar standards, 434 by 303 miles with indistinct walls. Lunar seas are actually huge craters with an age over 3 billion years.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon's Oceanus Procellarum. Image from the Virtual Moon Atlas.
07/08/11 – Ephemeris – Viewing night Saturday at the Rogers Observatory
Friday, July 8th. Today the sun will be up for 15 hours and 23 minutes, setting at 9:29. The moon, at first quarter today, will set at 1:14 tomorrow morning. Tomorrow the sun will rise at 6:06.
Tomorrow evening there will be a viewing night at Northwestern Michigan College’s Joseph H. Rogers Observatory. On tap if it’s clear will be Saturn and the moon plus the brighter deep sky objects, that is telescopic objects that are beyond the solar system. Saturn is the planet to see in a telescope with it’s fantastic rings. The moon will reveal its wonders including the great Copernicus crater, 56 miles wide and two miles deep with a triple central peak and terraced walls. The observatory hill is also good vantage point to view the Cherry Festival fireworks where they’re not so loud. The observatory is located south of Traverse City on Birmley Road between Garfield and Keystone roads.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/07/11 – Ephemeris – Demonstrate for yourself the phases of the moon
Thursday, July 7th. Today the sun will be up for 15 hours and 24 minutes, setting at 9:29. The moon, 1 day before first quarter, will set at 12:43 tomorrow morning. Tomorrow the sun will rise at 6:05.
The moon changes its phase daily as it orbits the earth. Some still think that it has to do with the earth’s shadow. Now that does happen for a few hours during a lunar eclipse at some full moons. However the moon’s phase is simply the moon in sunlight, the same sunlight that falls on the earth. The dark part of the moon is simply the night side of the moon. It changes because the moon orbits the earth and the farther it appears from the sun, the fuller it appears. This can be proven with a small ball. When the moon’s out in the day time, like it is now before sunset, go out in the sunshine and hold or toss the ball up in the direction of the moon. The ball will have the same phase as the moon.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/06/11 – Ephemeris – The bright planets this week
Wednesday, July 6th. Today the sun will be up for 15 hours and 25 minutes, setting at 9:29. The moon, 2 days before first quarter, will set at 12:15 tomorrow morning. Tomorrow the sun will rise at 6:04.
It’s Wednesday and time again to take a look at the whereabouts of the bright planets. The ringed planet Saturn will be visible in the southwest as it gets dark. It’s near the bright star Spica to its left. Spica has a blue tinge, while Saturn is yellowish. It will set at 1:26 a.m. Saturn is a wonderful sight is a telescope with its rings. The shadows of the rings on the planet and planet on the rings are now near their maximum extent. Its bright moon Titan is also visible. Folks with good telescopes and good eyesight can also see up to four of Saturn’s fainter moons. Jupiter will rise at 2:05 a.m. in the east. Mars will rise at 3:43 in the east northeast. Venus and Mercury are too close to the sun to be seen.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
07/05/11 – Ephemeris – The ancient’s perfect moon
Tuesday, July 5th. Today the sun will be up for 15 hours and 26 minutes, setting at 9:30. The moon, 3 days before first quarter, will set at 11:49 this evening. Tomorrow the sun will rise at 6:04.
As we look at the moon tonight we can see dark areas and bright areas. To western philosophers and astronomers from Aristotle to Copernicus objects in the heavens were thought to be perfect and changeless and moved in uniform circular motion around the earth. However the moon doesn’t appear perfect and spotless. It has light and dark areas on it. The supposed explanation for that was that it was a perfect mirror and reflected the earth. It might make sense if you didn’t think about it too much. For a very long time nobody did, at least nobody that made a difference until Copernicus came along. With Copernicus, Galileo and his telescope, Tycho Brahe’s observations, Kepler and Newton, the heavens were changed forever.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Bob Moler's Ephemeris Blog 