Archive
09/12/11 – Ephemeris – Harvest Moon tonight
Monday, September 12th. The sun will rise at 7:17. It’ll be up for 12 hours and 41 minutes, setting at 7:59. The moon, at full today, will rise at 7:43 this evening.
Today’s full moon is the famous Harvest Moon, the nearest full moon to the autumnal equinox. This is a time of the full and waning gibbous moons in the next few days rising in twilight. In the old days before electric lights it helped farmers by effectively lengthening the hours of light to gather in the crops. The moon on average rises 50 minutes later each night. The interval between tonight’s moonrise and tomorrow’s will be 22 minutes. The interval between Tuesday and Wednesday will be 24 minutes, between Wednesday and Thursday, 27 minutes. The instant of full moon today is actually past, at 5:26 this morning. The fact that the rising moon appears orange has nothing to do with the Harvest Moon. Like the sun, it’s always orange or red near the horizon.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/09/11 – Ephemeris – Star party Saturday September 10th, 2011 at the Sleeping Bear Dunes
Friday, September 9th. The sun will rise at 7:14. It’ll be up for 12 hours and 50 minutes, setting at 8:04. The moon, 3 days before full, will set at 5:32 tomorrow morning.
Tomorrow is the Grand Traverse Astronomical Society’s 4th star party of 2011 at the Sleeping Bear Dunes National Lakeshore. This time we’ll be at the Dune Climb. The bottom, not the top, in or near the parking lot. We’ll have the bright moon early. We’ll be also looking at binary stars, star clusters and the Ring Nebula. Toward the end of the evening Jupiter will be high enough to view. The event will be canceled if it’s too cloudy. There will be another star party, this one to celebrate the Lakeshore’s 41st anniversary in October, so stay tuned for that one. So far we’ve had no outright cancellations, but two of the nights were hampered by clouds. Our one absolutely clear night cleared just after sunset, and after an earlier rain shower.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/08/11 – Ephemeris – The moon tonight
Thursday, September 8th. The sun will rise at 7:12. It’ll be up for 12 hours and 53 minutes, setting at 8:06. The moon, half way from first quarter to full, will set at 4:28 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 bright crater Aristarchus is just coming into sunlight now on the upper left. It’s the brightest spot on the moon when the moon is full. 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 distinctively elongated.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon with craters Aristarchus, Gassendi and Schiller. Image from Virtual Moon Atlas.
Closeup of the crater Gassendi
The crater Gassendi from Apollo 16 - NASA
09/07/11 – Ephemeris – The bright planets visible this week
Wednesday, September 7th. The sun will rise at 7:11. It’ll be up for 12 hours and 56 minutes, setting at 8:08. The moon, 3 days past first quarter, will set at 3:23 tomorrow morning.
It’s Wednesday and time again to take a look at the whereabouts of the bright planets. The ringed planet Saturn will be barely visible in the west southwest in evening twilight. It’s near the bright star Spica to its left. Spica has a blue tinge, while Saturn is yellowish. It will set at 9:25 p.m. Because we are seeing Saturn in evening twilight now its image is being deteriorated by the earth’s atmosphere being low in the sky. Jupiter will rise at 10:10 p.m. in the east northeast and is seen against the stars of the constellation Aries now. Mars will rise at 2:36 a.m also in the east northeast and is now passing through the constellation Gemini the twins. Mercury is briefly visible now from about half an hour after its rising in the east at 5:43 until about 20 minutes before sunrise.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/06/11 – Ephemeris – Comet Elenin self-destructs
Tuesday, September 6th. The sun will rise at 7:10. It’ll be up for 12 hours and 59 minutes, setting at 8:10. The moon, 2 days past first quarter, will set at 2:17 tomorrow morning.
When Comet Elenin was discovered by Russian astronomer Leonid Elenin using a remotely controlled telescope in New Mexico on December 10th of last year, it was hoped that it would become a bright comet in our skies next month. It would pass between the earth and the sun this month and move ahead of the earth to be briefly a bright comet in the morning sky. Last week astronomers from the southern hemisphere saw its nucleus suddenly elongate and the comet dropped in brightness. It appears that the small solid part of the comet is breaking up. Comets do this on occasion. About 10 years ago or so one of the many Comet Linears simply exploded sending out hundreds of pieces of its nucleus, which evaporated and disappeared.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/05/11 – Ephemeris – Mercury is visible in the morning
Labor Day, Monday, September 5th. The sun will rise at 7:09. It’ll be up for 13 hours and 2 minutes, setting at 8:12. The moon, 1 day past first quarter, will set at 1:13 tomorrow morning.
The planet Mercury is now very low in the eastern sky before sunrise. This tiny planet was at its greatest apparent distance from the sun yesterday. Astronomers call it greatest elongation and its separation from the sun was an 18 degree angle. Mercury will be very close to the east northeast horizon in the 6:30 a.m. twilight. Once found, you can probably follow it for the next 20 minutes or so. Mercury will be visible for the next week of so. The cool thing is that it will become brighter. It’s illuminated by the sun, and as it moves away from us around the sun its phase or illuminated portion from our vantage point becomes larger. Currently Mercury is being studied up close by the MESSENGER spacecraft now orbiting it.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mercury in the morning in early September 2011. Chrat created using Stellarium.
09/02/11 – Ephemeris – Local astronomical events this weekend
Friday, September 2nd. The sun will rise at 7:05. It’ll be up for 13 hours and 11 minutes, setting at 8:17. The moon, 2 days before first quarter, will set at 10:33 this evening.
Impact glass, the earthly sand, fused by the impacts of meteorites will be the topic at this evening’s meeting of the Grand Traverse Astronomical Society at 8 p.m. at Northwestern Michigan College’s Rogers Observatory. Society President Richard Kuschell has become fascinated with meteorites and this impact glass and has several samples to show. As always the public is welcome. Tomorrow evening the society will host a public viewing night at the observatory. On tap, if it’s clear will be the moon and later in the evening Jupiter. The sky will also be dark enough to view some of the wonders of the summer Milky Way. The observatory is located south of Traverse City of Birmley Roan between Garfield and Keystone roads.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/01/11 – Ephemeris – Preview of September skies
Thursday, September 1st. The sun will rise at 7:04. It’ll be up for 13 hours and 14 minutes, setting at 8:19. The moon, 3 days before first quarter, will set at 9:53 this evening.
Let’s look at the skies for the month of September. The sun will 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 14 minutes today to 11 hours 46 minutes on the 30th. The altitude of the sun above the southern horizon at local noon will be 54 degrees today, and will descend to 42 degrees on the 30th. The Straits area will see the sun a degree lower. The season of summer is getting short, so enjoy it while you can. Summer ends and autumn begins at 5:05 a.m. on September 23rd. We are losing Saturn into the evening twilight but it will be replaced in the evening sky by Jupiter rising earlier by a half hour each week.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/31/11 – Ephemeris – The bright planets for this week
Wednesday, August 31st. The sun will rise at 7:03. It’ll be up for 13 hours and 17 minutes, setting at 8:21. The moon, 3 days past new, will set at 9:19 this evening.
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 in evening twilight. It’s near the bright star Spica to its left. Spica has a blue tinge, while Saturn is yellowish. It will set at 9:50 p.m. Saturn is a wonderful sight is a telescope with its rings. We are seeing Saturn in evening twilight now. Its image is being deteriorated by the earth’s atmosphere being low in the sky. Jupiter will rise at 10:37 p.m. in the east northeast and is seen against the stars of the constellation Aries now. Mars will rise at 2:42 a.m also in the east northeast and is now passing through the constellation Gemini the twins. Venus, now in the evening sky, is 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.
08/30/11 – Ephemeris – The bright star Altair
Tuesday, August 30th. The sun will rise at 7:02. It’ll be up for 13 hours and 20 minutes, setting at 8:23. The moon, 2 days past new, will set at 8:48 this evening.
The Summer Triangle of bright stars is visible overhead and to the south.. Vega is highest, nearly overhead, while Deneb is high in the northeast. The southernmost star of the Summer Triangle is Altair. Altair is the closest of the three stars 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 6 ½ to 10 hours, and would show a decidedly squashed appearance if seen close up. Our sun’s a slow poke, taking nearly a month to rotate just once.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
