Archive
11/06/2012 – Ephemeris – Pluto: an example of what happens when you don’t vote
Ephemeris for Election Day, Tuesday, November 6th. The sun will rise at 7:27. It’ll be up for 9 hours and 56 minutes, setting at 5:24. The moon, at last quarter today, will rise at 12:06 tomorrow morning.
Be sure and vote today. I have a tale of what happens when a low turn out leads for many to the wrong result. I’m referring to the vote at the International Astronomical Union meeting in 2006 that demoted Pluto to dwarf planet. It was the last day of the conference and many delegates had already left when the when the matter of defining what a planet was. A hastily formed proposal won the day. I haven’t the time to go into the definition, but Pluto didn’t fit it. Pluto, Eris the Kuiper belt object that caused the furor in the first place and the asteroid Ceres were given the titles dwarf planet because they are round. To add insult to injury Pluto was given an asteroid number 13430. That Pluto has 5 moons doesn’t change anything.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here’s the IAU definition of a planet:
(1) A “planet” is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.
(2) A “dwarf planet” is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.
(3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as “Small Solar System Bodies”.
Note the mention of the sun in all three points. Thus this does not apply to exoplanets, those orbiting other stars. We are a long way from seeing and assessing all the bodies orbiting other stars, so it may be that every stellar system will have its own rules.
Oh by the way, I have come to agree with the IAU definition. Sorry, there are only 8 planets in our solar system.
11/05/2012 – Ephemeris – The zodiacal constellation of Aquarius
Ephemeris for Monday, November 5th. The sun will rise at 7:26. It’ll be up for 9 hours and 59 minutes, setting at 5:25. The moon, 1 day before last quarter, will rise at 11:02 this evening.
One of the constellations of the zodiac is in the south sky at 9 in the evening. It’s the constellation of Aquarius the water bearer. The image that is supposed to be depicted in the stars is that of a hapless fellow spilling a stone jar of water across the sky. Aquarius is fairly hard to spot because it is made of faint stars. One part of him, though, is easy to spot. That is the Water Jar, an asterism or informal constellation. It is a distinctive small nearly equilateral triangle of stars with another star in the center. Stars extending to the right from the water jar are that stream of water. The Water Jar is just below the top of the head of the upside down Pegasus the flying horse. The body of Aquarius is below, a misshapen deflated balloon of stars.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aquarius and surrounding constellations 9 p.m. November 5, 2012. Created using Cart duCiel (Sky Charts)
11/02/2012 – Ephemeris – Astronomy tonight!
Ephemeris for Friday, November 2nd. The sun will rise at 8:22. It’ll be up for 10 hours and 7 minutes, setting at 6:29. The moon, half way from full to last quarter, will rise at 9:10 this evening.
Previewing the comets of 2013 will be the topic at the Grand Traverse Astronomical Society’s monthly meeting at 8 p.m. at Northwestern Michigan College’s Rogers Observatory. The program will be given by yours truly. Next year we may be treated by the possibility of two bright comets: PanSTARRS and ISON The questions isn’t will they arrive, they will; but how bright will they be. ISON in particular, could be spectacular. Starting at 9 p.m. will be the monthly viewing night at the observatory. On tap if its clear will be the galaxies of fall along with Jupiter and the moon rising. The Observatory is located south of Traverse City on Birmley Road off either Garfield or Keystone roads.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
11/01/2012 – Ephemeris – Previewing November Skies
Ephemeris for Thursday, November 1st. The sun will rise at 8:20. It’ll be up for 10 hours and 9 minutes, setting at 6:30. The moon, 3 days past full, will rise at 8:21 this evening.
Tonight Jupiter will appear above the moon. The month of November is one early sunsets, especially with the return to standard time this Sunday, and shortening of day light hours. Daylight hours will decrease from 10 hours 9 minutes today to 9 hours 5 minutes at month end. The altitude of the sun above the southern horizon at local noon, will drop from 31 degrees to 23½ degrees over the month. The Leonid meteor shower will have two peaks this year, but the best for us will be at 2 a.m. on the morning of the 20th. Up to 15 meteors per hour are expected. These are from Comet Tempel-Tuttle’s 1400 AD passage through the inner solar system. It won’t be until the late 2030’s when the comet will come around again.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter and the moon at 10 p.m. November 1, 2012. Created using Stellarium.
Leo rising at around 2 a.m. on the morning of November 20. Note the radiant in the sickle asterism of Leo. Created using Looking Up, my own program.
10/31/2012 – Epmeneris – The Ghoul Star
Ephemeris for Halloween, Wednesday, October 31st. The sun will rise at 8:19. It’ll be up for 10 hours and 12 minutes, setting at 6:32. The moon, 2 days past full, will rise at 7:37 this evening.
Not all the ghosts and goblins out tonight will be children. One will be out every night, because it’s a star. Its name is Algol, from the Arabic for Ghoul Star or Demon Star. The Chinese had a name for it that meant a mausoleum or more ominously ‘piled up corpses’. It’s the second brightest star in the constellation Perseus the hero, rising in the northeast this evening. The star is located where artists have drawn the severed head of Medusa, whom he had slain. Medusa was so ugly that she turned all who gazed upon her to stone. Algol is her still glittering eye. Astronomers finally found out what was wrong with Algol. It does a slow 6 hour wink every two days 21 hours, because it is two very close stars that eclipse each other in that period.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The constellation Perseus in the northeast at 9 p.m. on October 31, 2012. Created using Stellarium.
Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius. Image found with the article on Algol in Wikipedia.
Note that this is a mirror image. The star charts in the 17th century were based on celestial globes, which represented the constellations as seen from the outside of the celestial sphere instead of from the inside. I reversed the image to match Perseus as we see him.
10/30/2012 – Ephemeris – Where are the bright planets this week?
Ephemeris for Tuesday, October 30th. The sun will rise at 8:18. It’ll be up for 10 hours and 15 minutes, setting at 6:33. The moon, 1 day past full, will rise at 6:58 this evening.
Let’s check out the planets for this week, a day early. At 7:30 p.m. Mars can be seen low in the southwest moving away from the red star Antares, whose name means rival of Mars. Mars will set at 8:26. The planetary action will have already picked up on the other side of the sky. Jupiter, will rise at 8:18 p.m. in the east northeast. It is located in the constellation of Taurus. It will transit or pass due south at 3:54 a.m. The last bright planet of the night is the morning star Venus which will rise at 5:16 a.m. also in the east. Venus is now below the hind end of Leo, and entering the constellation of Virgo. The planets Venus and Jupiter and the winter constellations are a great sight for early risers. It’s starting to feel like winter in the early morning.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars and stars at 7:20 p.m. on October 30, 2012. Created using Stellarium.
Mercury, though labeled, is not visible. Folks much farther south of us have a better shot at seeing it.
Jupiter, the moon and the stars of Taurus and Auriga at 9:30 p.m. October 30, 2012. Created using Stellarium.
Jupiter and Venus with the winter stars at 6 a.m. on October 31, 2012. Created using Stellarium.
10/29/2012 – Ephemeris – The full Hunters Moon and Tycho’s rays
Ephemeris for Monday, October 29th. The sun will rise at 8:16. It’ll be up for 10 hours and 18 minutes, setting at 6:34. The moon, at full today, will rise at 6:24 this evening.
The full moon tonight is the full Hunters Moon. As down as I am about full moons due to the fact that they light up the sky and flood out the dimmer objects in the sky, I once and a while stop and view it. The time of the full moon is about 3 this afternoon, so when it rises tonight we will be looking at the moon from very nearly the direction of the sun, so there will be few shadows to be had. Last week I talked about the crater Tycho near the bottom or south end of the moon and its long rays of ejecta. The full moon is the best time to see these rays, which are easily visible in binoculars, through which Tycho itself looks like a bright dot. In telescopes Tycho looks like a small bright ring. The full moon is super bright. It’s daytime there.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Photographed with a Celestron 9.25 Schmidt-Cassegrain telescope. Acquired with a Canon EOS Rebel T1i (EOS 500D), 20 images stacked to reduce noise. 200 ISO 1/640 sec. Gregory H. Revera
Tycho and its rays are prominent in the photo above. I found this image in the article Moon in Wikipedia.
10/25/2012 – Ephemeris – Exploring the bright gibbous moon
Ephemeris for Thursday, October 25th. The sun will rise at 8:11. It’ll be up for 10 hours and 29 minutes, setting at 6:40. The moon, half way from first quarter to full, will set at 5:02 tomorrow morning.
The moon tonight is very bright, so looking at it with a telescope can be almost painful. There are moon filters sold at telescope stores for standard sized eyepieces that will alleviate that problem. Remember it’s daytime on the moon and the sunlight is as strong on the moon as it is on the earth. Concentrate the telescope on the left edge of the moon, the sunrise line where the shadows are. The small crater Kepler, named for the astronomer who gave us the laws the govern the motion of the planets is located near the terminator near the moon’s equator. The Crater Gassendi, to the lower left, is a ringed plain with low walls and a flat floor that has a rille or crack in it. Another distinctive crater is Schiller lower to the south and very elongated.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The bright gibbous moon highlighting three craters, Kepler, Gassendi, and Schiller. Created using the Virtual Moon Atlas.
Gassendi is named for Pierre Gassend, 17th French astronomer and pioneer in the use of a refractor telescope. Schiller is named for Julius Schiller a 17th century monk who came out with a Christian themed star atlas. These and other crater facts were obtained for the open source lunar program Virtual Moon Atlas.
10/24/2012 – Ephemeris – Whare are all the bright planets this week?
Ephemeris for Wednesday, October 24th. The sun will rise at 8:10. It’ll be up for 10 hours and 32 minutes, setting at 6:42. The moon, 3 days past first quarter, will set at 3:58 tomorrow morning.
Let’s see how many bright planets we can find this week. At 7:30 p.m. Mars can be seen low in the southwest moving away from the red star Antares, whose name means rival of Mars. Mars will set at 8:35. The planetary action will resume a few minutes later. Jupiter, will rise at 8:48 p.m. in the east northeast. It is located in the constellation of Taurus. It will transit or pass due south at 4:24 a.m. The last bright planet of the night is the morning star Venus which will rise at 5 a.m. also in the east. Venus is now below the hind end of Leo, and entering the constellation of Virgo. The planets Venus and Jupiter and the winter constellations are a great sight for early risers. You can enjoy for a few more weeks without danger of frost bite.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars, Antares, and the Teapot of Sagittarius low in the southwest at 7:30 p.m. on October 24, 2012. Created using Stellarium.
Jupiter in the east at 10 p.m. October 24, 2012. Created using Stellarium.
The morning skies with Jupiter and Venus at 6 a.m. on October 25, 2012. Created using Stellarium.
10/23/2012 – Ephemeris – The remarkable lunar crater Tycho
Ephemeris for Tuesday, October 23rd. The sun will rise at 8:08. It’ll be up for 10 hours and 35 minutes, setting at 6:44. The moon, 2 days past first quarter, will set at 2:52 tomorrow morning.
Tonight the moon’s advancing sunrise line will reveal a young crater near the bottom of the moon. That crater is Tycho. In binoculars or a telescope it’s features appear sharper, and its floor deeper than the surrounding craters. Its age is in the range of hundreds of thousands of years rather than billions. Tycho has an extensive ray system that extends thousands of miles across the face of the moon. That is best seen at full moon, and the rays are probably a huge number of craterlets. They are normally shadow filled but at full moon are fully illuminated accentuating the brightness of the rays. The crater was named for 16th Century Danish astronomer Tycho Brahe, the greatest observational astronomer before the invention of the telescope. [ His observations allowed Kepler to formulate his three laws of planetary motion.]
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The crater Tycho and one of its rays at 9 p.m. on October 23 2012. Created using Virtual Moon Atlas.
