Archive
08/31/2012 – Ephemeris – Once in a blue moon
Ephemeris for Friday, August 31st. The sun will rise at 7:04. It’ll be up for 13 hours and 15 minutes, setting at 8:19. The moon, at full today, will rise at 8:01 this evening.
Tonight’s moon has been dubbed by some to be a Blue Moon. No the color of the moon isn’t really blue. But it is as rare as a blue moon. Let me try to explain. Currently the label blue Moon is given to the second full moon in a month. August’s first full moon was on the first. This blue moon rule wasn’t always the case. Early American almanacs apparently gave the title of blue moon to the 4th full moon in a season. So could the moon ever appear blue? Yes it can. If seen through a lot of dust in a dust storm. A totally eclipsed moon can appear very dark and even have a blue tinge if there’s a lot of volcanic ash in the atmosphere. I’ve seen two of these eclipses and the moon didn’t appear blue to my eyes, but it was so dim the I could barely make it out without binoculars.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/30/2012 – Ephemeris – Previewing September skies
Ephemeris for Thursday, August 30th. The sun will rise at 7:03. It’ll be up for 13 hours and 18 minutes, setting at 8:21. The moon, 1 day before full, will set at 7:12 tomorrow morning.
Let’s look ahead at the skies for September a couple of days early. The sun is moving at its greatest speed in its retreat to the south. Daylight hours in the Interlochen/Traverse City area and will drop from 13 hours and 12 minutes Saturday to 11 hours 44 minutes on the 30th. The altitude of the sun above the southern horizon at local noon will be 54 degrees Saturday, and will descend to 42 degrees on the 30th. Folks in the straits area will see the sun a degree lower than that. The official season of summer is getting short too, so enjoy it while you can. Summer ends and autumn begins at 10:49 a.m. on September 22nd. That Harvest Moon will be on the 29th. Tomorrows full moon will be the rare Blue Moon – More on that tomorrow.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/29/2012 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, August 29th. The sun will rise at 7:02. It’ll be up for 13 hours and 21 minutes, setting at 8:23. The moon, 2 days before full, will set at 6:04 tomorrow morning.
Let’s see what’s happening with the bright planets for this week. Mars Saturn and the star Spica make a bright but elongating triangle in the west southwest after sunset. Mars is on the upper left with Saturn on the upper right and Spica below. They are located in the constellation Virgo the virgin. Saturn will be setting in the west at 10:20 p.m, and Mars will set 3 minutes later. The morning sky features the two brightest planets: Jupiter, which will rise at 12:23 a.m. in the east northeast and Venus, which will rise at 3:16 also in the east northeast. Jupiter is near the head of Taurus the bull, while Venus is moving between Gemini and Cancer. Early morning is a good time to get a preview of winter stars.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars, Saturn and Spica at 9:30 p.m. on August 29, 2012. Created using Stellarium.
Jupiter, Venus and the stars of winter rising at 5:30 a.m. on August 30, 2012. Created using Stellarium.
08/28/2012 – Ephemeris – Altair, fatter in the middle
Ephemeris for Tuesday, August 28th. The sun will rise at 7:00. It’ll be up for 13 hours and 24 minutes, setting at 8:25. The moon, 3 days before full, will set at 4:54 tomorrow morning.
The southernmost star of the Summer Triangle is Altair, high in the south. The other two stars of the triangle are Vega nearly overhead, and Deneb high in the east. Altair is the closest of the three at a distance of 16.8 light years away. One light year is nearly 6 trillion miles. Altair is 10 times the brightness of the sun. If seen at Altair’s distance, the sun would only be as bright as one of the two stars that flank it. What is rather different about Altair is it’s rapid rotation. While its almost twice the sun’s diameter, it rotates once in only 9 hours, and has a decidedly squashed appearance when seen close up. There are techniques that can actually accomplish this. Our sun’s a slow poke, taking nearly a month to rotate once.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The constellations Lyra, Cygnus and Aquila. Created using Stellarium.
Check out Altair to the lower right.
08/27/2012 – Ephemeris – RIP: Neil Armstrong
Ephemeris for Monday, August 27th. The sun will rise at 6:59. It’ll be up for 13 hours and 27 minutes, setting at 8:27. The moon, 3 days past first quarter, will set at 3:44 tomorrow morning.
Over the weekend we learned that Neil Armstrong, the first human to step on the moon, passed away at age 82. I am old enough to remember all of the space age from Sputnik to Curiosity’s landing on Mars. The Apollo 11 landing and subsequent lunar EVA or moon walk were riveting to me and all the world. Neil was an engineer and understood the flying machines he flew implicitly, whether it was the X15, Gemini, Apollo Command Module or the Lunar Module. He stayed an engineer and became a college professor after he returned to earth, not cashing in on his fame. He is a hero in a time that has no true heroes. He will be remembered as long as humanity strives to reach the stars.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/24/2012 – Ephemeris – A star party tomorrow night
Ephemeris for Friday, August 24th. The sun rises at 6:56. It’ll be up for 13 hours and 36 minutes, setting at 8:32. The moon, at first quarter today, will set at 12:32 tomorrow morning.
Tomorrow evening there will be a star party 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. We will soon lose it into the setting sun. The moon will reveal its wonders including its great craters and lava seas. Members of the Grand Traverse Astronomical Society and the NMC Astronomy Club team up for these star parties. 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.
08/23/2012 – Ephemeris – A belated salute to Curiosity
Ephemeris for Thursday, August 23rd. The sun rises at 6:55. It’ll be up for 13 hours and 38 minutes, setting at 8:34. The moon, 1 day before first quarter, will set at 11:41 this evening.
It’s been two and a half weeks since the Curiosity Rover landed on Mars. I finished the prior two weeks programs less than an hour before Curiosity landed and before heading off for vacation, so this is my first opportunity to talk about the landing. The so-called “Seven Minutes of Terror” went without a hitch. Either receiving transmissions directly from the spacecraft or through the Odyssey Mars orbiter, tones from the spacecraft ticked off the landing milestones right on time. As I’m recording this Curiosity hasn’t moved, however it’s already zapped a rock with its laser, its delivered a panorama of its surroundings, and is still sending frames of the descent movie it took when the heat shield was dropped, until it touched down.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here’s a mix from the Seven Minutes of Terror video created before landing cut with actual Jet Propulsion Laboratory (JPL) Mission Control footage as Curiosity actually landed.
Here’s another video of the landing cut with scenes of gatherings around the country including Times Square, and video from the landing imager and Curiosity descending on the parachute from the Mars Reconnaissance Orbiter.
Here is a hi-res descent and landing from the MARDI landing imager. Hat tip to the Bad Astronomer. Play at full screen for best effect.
08/22/2012 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, August 22nd. The sun rises at 6:53. It’ll be up for 13 hours and 41 minutes, setting at 8:35. The moon, 2 days before first quarter, will set at 10:58 this evening. | Let’s see what’s happening with the bright planets for this week. Mars Saturn and the star Spica make a bright triangle in the west southwest after sunset. Mars is on the upper left with Saturn on the upper right and Spica below. They are located in the constellation Virgo the virgin. Mars will be setting in the west at 10:41 p.m, and Saturn will set at 11:46. The morning sky features the two brightest planets: Jupiter, which will rise at 12:47 a.m. in the east northeast and Venus, which will rise at 3:11 also in the east northeast. Venus’ rising times are now getting later after its greatest elongation last week. The bright star Aldebaran in Taurus the bull will appear just to the right and a bit below Jupiter tomorrow morning
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The planets and the moon low in the west southwest at 9:30 p.m. Created using Stellarium.
Venus, Jupiter and the winter stars at 5:30 a.m. on August 23rd. Created using Stellarium.
08/21/2012 – Ephemeris – The moon, the planets Mars, Saturn and the star Spica get together tonight
Ephemeris for Tuesday, August 21st. The sun rises at 6:52. It’ll be up for 13 hours and 44 minutes, setting at 8:37. The moon, 3 days before first quarter, will set at 10:21 this evening.
Tonight the moon will join the triangle of the planets Saturn, Mars and the star Spica. Mars is the dimmest of the three star-like objects and is nearly directly above the moon. Saturn is yellowish and to the upper right, while the star Spica is the bluest of the 21 brightest first magnitude stars. Mars gets its color from rust, good old iron oxide. Saturn has a yellowish tinge due partly to the color of its cloud tops. The color of the rings is much more white of ice. But since Saturn reflects the sun, some of that yellowness come from the sun itself. While the daylight sun appears white to us, our night vision shifts to the blue, so sunlike stars appear yellowish. This shift to the blue also enhances the color of a blue star like Spica.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon and the planets Mars and Saturn plus the bright star Spica before 10 p.m. Created using Stellarium.
Spica is the unnamed star to the right of the moon.
08/20/2012 – Ephemeris – Celestial Dolphin and Cupid’s dart
Ephemeris for Monday, August 20th. The sun rises at 6:51. It’ll be up for 13 hours and 47 minutes, setting at 8:39. The moon, 3 days past new, will set at 9:48 this evening.
Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is nearly overhead sky at 10 p.m., is the tiny constellation of Delphinus the dolphin, which is seen high in the south. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do, and told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow, which represents Cupid’s dart. [Off the tail of Sagitta binoculars will find a cute inverted coat hanger in the stars.]
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location. Bracketed text was removed from the audio program due to time constraints.
Addendum
Delphinus, Sagitta and the Coat hanger. Diagram created using Stellarium.
Bob Moler's Ephemeris Blog 