Archive
01/31/2012 – Ephemeris – February preview
Ephemeris for Tuesday, January 31st. The sun will rise at 8:02. It’ll be up for 9 hours and 46 minutes, setting at 5:49. The moon, 1 day past first quarter, will set at 2:50 tomorrow morning.
Let’s preview the month of February. It will be a day longer this year because it’s a leap year, the adjustment to keep the calendar in sync with the seasons. The daylight hours throughout February will be getting longer. Daylight hours will increase from 9 hours and 48 minutes tomorrow to 11 hours and 8 minutes on the 29th. The altitude of the sun at noon will increase from 28 degrees tomorrow to nearly 38 degrees at month’s end. The straits area will see the sun a degree lower. Local noon, by the way for Interlochen and Traverse City is about 12:55 p.m, which is mainly due to the fact that our standard time meridian happens to run through Philadelphia and the sun is currently running 12 minutes slow.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
Sunrise planets at 5 day intervals for February 2012
Click on the image to animate.
Sunset planets at 5 day intervals for February 2012
Click on the image to animate.
01/30/2012 – Ephemeris – Getting Sirius about color
Ephemeris for Monday, January 30th. The sun will rise at 8:04. It’ll be up for 9 hours and 43 minutes, setting at 5:47. The moon, at first quarter today, will set at 1:51 tomorrow morning.
The bright star shining so bright low in the south southeast at 9 p.m. is Sirius the Dog Star. I talked about it Friday in the context of its constellation Canis Major, Orion’s larger hunting dog. Sirius itself is a remarkable star. It’s name means dazzling one and a look at it in binoculars or a telescope will prove it.. The twinkling effects are due to the earth’s atmosphere, but the bright arc light color is all his. Sirius is a perfect white star. Compare it with the brightest star now overhead Capella which has the same color as our sun. Star colors tell us the temperature of the star surfaces, which run from cool red to hot blue. On our Fahrenheit temperature scale, the sun’s surface is about 10,000 degrees, Sirius is nearly twice that.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
Orion and his Hunting Dogs. Created using Stellarium.
Sirius actually looks blue-white to me. Of course during the day our yellow sun looks white. I think it has to do with out night vision.
01/27/2012 – Ephemeris – The constellation Canis Major
Ephemeris for Friday, January 27th. The sun will rise at 8:07. It’ll be up for 9 hours and 36 minutes, setting at 5:43. The moon, 3 days before first quarter, will set at 10:49 this evening.
What kind of a hunter would the constellation Orion be without his trusty hunting dogs. The larger of the dogs is Canis Major which can be found if you extend Orion’s belt stars down to the left. There in the south southeast will appear the brightest night time star Sirius the Dog Star. It is in the heart of the dog, which appears to be begging. Well it’s tilted funny. Other than that it’s a pretty good representation of a dog as a stick figure. The name Sirius doesn’t mean Dog Star, but means Dazzling One due to its great brightness. It outshines all other night stars, only to be out shown by the planets Venus, Jupiter and occasionally Mars. Binoculars will show a nice little star cluster a short ways below Sirius known as M41.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
Orion and his Hunting Dogs. Created using Stellarium.
01/26/2012 – Ephemeris – The moon will appear near Venus tonight
Ephemeris for Thursday, January 26th. The sun will rise at 8:08. It’ll be up for 9 hours and 34 minutes, setting at 5:42. The moon, 3 days past new, will set at 9:46 this evening.
The waxing crescent moon will appear near the bright planet Venus tonight in the southwestern sky after sunset. They were actually closer earlier today, although not that close. The moon happens to be north of the ecliptic plane, which is actually the plane of the earth’s orbit of the sun. Venus is a bit below. The moon has to be close to that plane at new or full moon for eclipses to take place. The moon’s orbit is tilted at 5 degrees to that plane, and crosses it twice a month. So we get eclipse seasons twice a year. The next eclipse is a solar eclipse May 20th, which we’ll see the start of at sunset here. Venus will be close to that plane at its inferior conjunction June 5th when it passes in front of the sun in transit. We’ll see the first 3 hours of that before sunset.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
Venus and the moon on the evening January 26, 2012. Created using Stellarium.
01/25/2012 – Ephemeris – Where are the planets this week?
Ephemeris for Wednesday, January 25th. The sun will rise at 8:08. It’ll be up for 9 hours and 31 minutes, setting at 5:40. The moon, 2 days past new, will set at 8:42 this evening.
It’s time again to take a look at the whereabouts of the bright planets. Venus is brilliant in the southwestern sky after sunset and will set at 9:01 in the west. Jupiter is the most prominent planet of the evening sky, once Venus sets. It’s located high in the south southeast as it gets dark and is seen against the stars of the constellation Aries. It will pass due south at 6:21 p.m. and it will set at 1:08 a.m.. Mars will rise at 9:36 p.m in the east northeast and is below the hind end of the constellation Leo the lion. It is 76.7 million miles away and closing and has been getting brighter. It’s now as bright as most first magnitude stars. Mars will pass due south at 4:02 a.m. Saturn will rise at 12:49 a.m. just to the left of the bright star Spica in the east southeast.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
Mars 9 days ago. Photograph by Scott Anttila
Another gorgeous shot of Mars by Scott Anttila. At the time Mars appeared 10.3 seconds of arc in diameter. By comparison the moon and sun appear about 1,800 seconds of arc in diameter. Note that Mars appears slightly gibbous in shape. It will appear full on March 3rd. when it will be in opposition from the sun. It will be closest to us on March 5th. at about 62.6 million miles. At that time it will have an apparent diameter of 13.9 seconds of arc.
01/24/2012 – Ephemeris – The face of the constellation Taurus – The Hyades
Ephemeris for Tuesday, January 24th. The sun will rise at 8:09. It’ll be up for 9 hours and 29 minutes, setting at 5:39. The moon, 1 day past new, will set at 7:36 this evening.
To the upper right of the constellation Orion in the south in the evening is a letter V of stars with a bright orange star at one tip. This is the face of Taurus the bull. In some constellation depictions the bull is charging Orion who is turned to face him. The V of stars isn’t very bright and are outshone by the Pleiades star cluster to the right in Taurus’ shoulder. In Greek mythology the V of stars are the Hyades, half sisters of the Pleiades. It is a star cluster like the Pleiades and very important, because it is the closest star cluster to us at 153 light years distant. It helped determine the scale of the universe. The bright star at the tip is Aldebaran the follower (of the Pleiades). It is not part of the Hyades and is less than half way to it at 65 light years.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
The Hyades, Orion and the Pleiades. Created using Cartes du Ciel
01/23/2012 -Ephemeris – The constellation Gemini the twins
Ephemeris for Monday, January 23rd. The sun will rise at 8:10. It’ll be up for 9 hours and 27 minutes, setting at 5:38. The moon is new today, and won’t be visible.
The constellation of Gemini the twins appears high in the southeast. It appears to the upper left of Orion and the stars that portray his club raised high. Gemini’s two brightest stars are the namesakes of the twins. Castor above and Pollux below. From them there are two lines of stars that form the silhouette of the lads heading to the lower right. In Greek mythology these twins each had a different father, not unheard of in medical history, with Pollux being fathered by the god Zeus and thus immortal. Castor was not. But the brothers were inseparable, so when Castor was killed in the search for the golden fleece Pollux begged his father to let him die too and join his brother. His wish was granted and his devotion was so great that they were placed in the sky where we see them today.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
Gemini and Orion. Created using Cartes du Ciel
01/20/2012 – Ephemeris – The Great Orion Nebula part 2
Ephemeris for Friday, January 20th. The sun will rise at 8:13. It’ll be up for 9 hours and 21 minutes, setting at 5:34. The moon, 3 days before new, will rise at 6:44 tomorrow morning.
The closest star nursery to us is the Great Orion Nebula, It 1,344 light years away give or take 20 light years. A light year is about 6 trillion miles, if you want to pace it out. It’s located in the constellation Orion’s sword that hangs below his belt. It shines by emission and reflection of the light of a clutch of four stars at its heart, astronomers have called the Trapezium. These extremely hot baby stars which look like eggs in a nest are not destined to live long. Unlike the sun’s 10 billion year life time these stars lifespan will be measured in millions of years. Yet do not mourn for them, Even now stars are forming in their dusty cocoons in the nebula. The Trapezium stars death will provide the material for new stars and planets to form in their stead.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
The lower part of Orion with the Great Orion Nebula. Created using Stellarium.
Great Orion Nebula by Scott Anttila
Inner part of the Great Orion Nebula. Image by Scott Anttila
This short exposure by Scott Anttila shows the Trapezium. It’s a bit rotated and enlarged compared to the photograph above, but the red bars and the Trapezium match up.
01/19/2012 – Ephemeris – The moon will pass the bright star Antares this morning
Ephemeris for Thursday, January 19th. The sun will rise at 8:13. It’ll be up for 9 hours and 19 minutes, setting at 5:32. The moon, 3 days past last quarter, will rise at 5:52 tomorrow morning.
This morning, you might want to take a quick peek outside to the southeast and see, if you can spot the crescent moon. If you can below and a bit right of it is a bright red star. That star is Antares in the constellation Scorpius, one of the first constellations of summer to appear in the evening sky. I thought you’d like the encouragement that summer is coming now that winter has finally come in earnest. The moon passes Antares every month, but this morning it appears especially close, since their actual closest approach was about 2 this morning. The entire moon may be faintly visible this morning as earthshine. Antares itself may be twinkling merrily due to earth’s atmosphere. It sometimes looks like a sparkler in binoculars.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
Addendum
The Moon passes Antares in the morning hours of January 19, 2012. Created using Stellarium.
01/18/2012 – Ephemeris – Where are the bright planets this week
Ephemeris for Wednesday, January 18th. The sun will rise at 8:14. It’ll be up for 9 hours and 17 minutes, setting at 5:31. The moon, 2 days past last quarter, will rise at 4:51 tomorrow morning.
It’s time again to take a look at the whereabouts of the bright planets. Venus is brilliant in the southwestern sky after sunset and will set at 8:44. Jupiter is the most prominent planet of the evening sky, once Venus sets. It’s located high in the south and is seen against the stars of the constellation Aries. It will pass due south at 6:49 p.m. It will set at 1:36 a.m. Mars will rise at 10:03 p.m in the east northeast and is below the hind end of the constellation Leo the lion. It is 82.4 million miles away and closing. Mars will pass due south at 4:29 a.m. Saturn will rise at 1:15 a.m. just to the left of the bright star Spica in the east southeast.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
