Archive
06/26/2014 – Ephemeris – Draco the dragon is twisted around the pole of the sky
Ephemeris for Thursday, June 26th. Today the sun will be up for 15 hours and 32 minutes, setting at 9:31, the latest sunset. The moon, 1 day before new, will rise at 6:32 tomorrow morning. Tomorrow the sun will rise at 5:59.
High in the northern sky at 11 p.m. lies the twisted constellation, that of Draco the dragon. This dragon is more like the snakelike Chinese dragon than the dinosaur like dragon of European legend. I find it better to start at the tail of Draco, to trace him out in the stars. Draco’s tail starts between the bowl of the Big Dipper and the Little Dipper. The Dragon is seen in a line of stars that extends parallel to the handle of the Big Dipper before curving around the bowl of the Little Dipper then bends back toward the south. The head of Draco is an odd box of stars near the bright star Vega, high in the east. Though not made up of very bright stars, Draco has an easy shape to trace.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Draco via Stellarium in approximately the same orientation as the Jamieson atlas below. You’s have to face southeast and bend over backward to see this orientation in the sky.
Draco the Dragon as drawn in Alexander Jamieson’s 1820 Celestial Atlas as printer in Men, Monsters and the Modern Universe by George Lovi and Wil Tirion, 1989, Willmann-Bell, Richmond, VA
06/24/2014 – Ephemeris – The bright star Vega is high in the east
Ephemeris for Tuesday, June 24th. Today the sun will be up for 15 hours and 33 minutes, setting at 9:31. The moon, 3 days before new, will rise at 4:53 tomorrow morning. Tomorrow the sun will rise at 5:58.
The bright star high in the east is Vega, one of the stars of the Summer Triangle an informal constellation called an asterism. Vega belongs to the official constellation Lyra the harp, which includes a narrow parallelogram of stars to its south. Vega is regarded by astronomers as a standard calibration star. Though a first magnitude star, its actual magnitude is 0.03. It is a type A0 pure white star, and is 27 light years away. Astronomers however got a shock in 1983 when calibrating the Infrared Astronomy Satellite (IRAS) on it: Vega showed an excess of Infrared radiation that means the star is orbited by a disk of dust, perhaps the beginnings of a planetary system. Due to the slow wobble of the earth’s axis Vega will be our pole star in 14 thousand years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle. Created using Stellarium and The Gimp.
Vega in the mid-infrared from the Spitzer Space Telescope. Credit: NASA/JPL-Caltech/University of Arizona
06/23/2014 – Ephemeris – It’s summer, so where is the Summer Triangle?
Ephemeris for Monday, June 23rd. Today the sun will be up for 15 hours and 33 minutes, setting at 9:31. The moon, half way from last quarter to new, will rise at 4:09 tomorrow morning. Tomorrow the sun will rise at 5:58.
Now that it’s summer it’s time to look for the Summer Triangle in the sky. It’s seen rising in the east as it gets dark. Highest of the three bright stars is Vega in the constellation Lyra the harp, whose body is seen in a narrow parallelogram nearby. The second star of the triangle is Deneb lower and left of Vega, It appears dimmer than Vega because it is by far the most distant of the three. The third star of the Summer Triangle is seen farther below and a right of Vega. It is Altair in Aquila the eagle, and the closest. Altair is 16.5 light years away, Vega is 27 light years while Deneb actually one of the brighter stars known, is a whopping 2600 light years away, give or take. It’s distance is not well-known. (24 08:54 Venus 1.3°N of Moon)
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle. Created using Stellarium and The Gimp.
09-24-2013 – Ephemeris – The dragon in the sky
Ephemeris for Tuesday, September 24th. The sun will rise at 7:32. It’ll be up for 12 hours and 3 minutes, setting at 7:35. The moon, 2 days before last quarter, will rise at 10:40 this evening.
High in the northern sky at 9 p.m. lies a twisted constellation, that of Draco the dragon. This dragon is more like the snakelike Chinese dragon than the dinosaur like dragon of European legend. At least that’s how I see it. I find it better to start at the tail of Draco, to trace him out in the stars. Draco’s tail starts between the bowl of the Big Dipper and the Little Dipper. The Dragon is seen in a line of stars that extends parallel to the handle of the Big Dipper before curving around the bowl of the Little Dipper to the east then bends back toward the west. The head of Draco is an odd box of stars near the bright star Vega, nearly overhead. Though not made up of very bright stars, Draco has an easy shape to trace.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Draco and neighboring constellations at 9 .m. September 24, 2013. Created using Stellarium. Constellation art by Johan Meuris.
07/25/2013 – Ephemeris – Vega, the fifth brightest night-time star
Ephemeris for Thursday, July 25th. The sun rises at 6:21. It’ll be up for 14 hours and 54 minutes, setting at 9:15. The moon, 3 days past full, will rise at 10:43 this evening.
The star Vega, which is nearly overhead or the zenith is a special star for astronomers. It’s part of the small constellation of Lyra the harp, which includes the parallelogram of stars near it. Vega is kind of a standard calibration star. It is the 5th brightest night-time star with a brightness of 0 magnitude, although recent measurements place it at 0.03. Of the spectral types which denote the star’s color and surface temperature, Vega comes out to be pure white, with a surface temperature nearly twice the sun’s. It’s almost exactly 25 light years away, and so is one of the closer stars. It’s a tenth the sun’s age and 40 times the sun’s brightness. It has perhaps a Jupiter sized planet, and a Kuiper belt of Pluto like objects orbiting it.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Magnified view of Lyra showing Vega. Created using Stellarium.
07/04/2013 – Ephemeris – Patriotic Stars: Red, White and Blue
Ephemeris for Independence Day in the United States, Thursday, July 4th. Today the sun will be up for 15 hours and 27 minutes, setting at 9:30. The moon, half way from last quarter to new, will rise at 4:05 tomorrow morning. Tomorrow the sun will rise at 6:03.
Today is Independence Day so let’s look for some red, white, and blue stars. Red is easy, the red star Antares is seen in the south at 11 p.m. White is easy too, the official white calibration star Vega high in the east at 11 p.m. The blue star is really blue-white. The brightest of these out at 11 p.m. is Spica, low in the southwest to the right of the brighter Saturn. The color is best seen in binoculars. Star colors are quite subtle, and are an indicator of the temperature of their outer gaseous layers. The temperature of a stars outer layers, in order of their increasing temperatures are red, white and blue. Of these three the coolest on the outside, Antares is really the hottest inside, using helium as fuel.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Red Antares, white Vega and blue Spica. Patriotic Stars this evening. Created using Stellarium.
06/28/2013 – Ephemeris – Vega and Lyra the harp
Ephemeris for Friday, June 28th. Today the sun will be up for 15 hours and 31 minutes, setting at 9:31. The moon, 2 days before last quarter, will rise at 12:43 tomorrow morning. Tomorrow the sun will rise at 6:00.
One of the first stars visible when twilight fades is Vega. It will be east of the zenith and is perfectly white. Another bright star with a yellow-orange hue is to the west of the zenith. That’s Arcturus. We’re concentrating on Vega now. It is in a small constellation called Lyra the harp or lyre. Just off to the southeast of Vega as it gets dark is a narrow parallelogram of stars that make up the body of this celestial instrument. A dim star next to Vega completes the constellation. Take good look at it in binoculars and the star near Vega appears as two. It’s Epsilon Lyrae. Each can be split again in a telescope. Lyra has another wonder, but that will have to wait for another time.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Magnified view of Lyra. Created using Stellarium.
Epsilon Lyra is the closest star to Vega. Look closely, because it’s double. The funny characters next to “Lyr” are lower case Greek letters Epsilon is the Greek letter “e”. The one next to it is the slightly brightest star of the pair. The Greek letter designations are from Johannes Bayer’s 1603 atlas. The number designations are Flamsteed numbers. There’s other stars with proper names. The HIP number is from the Hipparcos catalog, a relatively new catalog.
06/26/2013 – Ephemeris – Latest sunset and the Summer Triangle
Ephemeris for Thursday, June 27th. Today the sun will be up for 15 hours and 32 minutes, setting at 9:31. The moon, 3 days before last quarter, will rise at 12:14 tomorrow morning. Tomorrow the sun will rise at 5:59.
Last night we had the latest sunset of the year. The sun is really beginning to head south. Other than the sunrise and sunset numbers, we’ll begin to notice it for real in a few weeks. At first that realization strikes me a sad note that summer is beginning to end. However the astronomer in me realizes that means more night-time hours, and that the summer Milky Way is coming. Of the three bright stars of the Summer Triangle overhead and in the east, two of its stars are in the milky band. They are Deneb to the north and Altair to the south. Vega, closest to the zenith is not in the band. Actually all the stars we see with the naked eye or small telescopes belong to the Milky Way galaxy.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle at 11 p.m. Created using Stellaruim and The Gimp.
07/23/2012 – Ephemeris – The star Vega up close
Ephemeris for Monday, July 23rd. The sun rises at 6:19. It’ll be up for 14 hours and 57 minutes, setting at 9:17. The moon, 3 days before first quarter, will set at 11:14 this evening.
The star Vega, which is high in the east, near overhead or the zenith is a special star for astronomers. It’s part of the small constellation or Lyra the harp, which includes the parallelogram of stars near it. Vega is kind of a standard calibration star. It is the 5th brightest night time star with a brightness of 0.0 magnitude, although recent measurements place it at 0.03. Of the spectral types which denote the star’s color and surface temperature, Vega comes out to be pure white, with a surface temperature nearly twice the sun’s. It’s almost exactly 25 light years away, and so is one of the closer stars. It’s a tenth the sun’s age and 40 times the sun’s brightness. [It has perhaps a Jupiter sized planet, and a Kuiper belt of Pluto like objects.]
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Lyra in Binoculars. Created using Stellarium.
07/16/2012 – Ephemeris – The constellation Draco the dragon
Ephemeris for Monday, July 16th. Today the sun will be up for 15 hours and 10 minutes, setting at 9:23. The moon, 3 days before new, will rise at 4:50 tomorrow morning. Tomorrow the sun will rise at 6:13.
High in the northern sky at 11 p.m. lies a twisted constellation, that of Draco the dragon. This dragon is more like the snake-like Chinese dragon than the dinosaur like Hungarian Horntail of Harry Potter fame. At least that’s how I see it. I find it better to start at the tail of Draco, to trace him out in the stars. Draco’s tail starts between the bowl of the Big Dipper and the Little Dipper. The Dragon is seen in a line of stars that extends parallel to the handle of the Big Dipper before curving around the bowl of the Little Dipper then bends back toward the south. The head of Draco is an odd box of stars near the bright star Vega, nearly overhead. Though not made up of very bright stars, Draco has an easy shape to trace.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Draco the dragon at 11 p.m. July 16th looking high in the north. Created using Stellarium.
Click on the image to enlarge.
Bob Moler's Ephemeris Blog 