Archive
08/25/2014 – Ephemeris – Cool treasures in the constellation of Lyra
Ephemeris for Monday, August 25th. The sun rises at 6:56. It’ll be up for 13 hours and 34 minutes, setting at 8:31. The moon is new today, and won’t be visible.
The bright star Vega will be nearly overhead tonight at 10 p.m. It will be about 6 degrees south of the zenith. That’s quite a stretch of the neck to spot, with its accompanying stars in a small parallelogram that make up the constellation of Lyra the harp. Lyra has some interesting features for a serious observer with and without a telescope. The bottom right star of the parallelogram, if south is toward the bottom, is a star called Beta Lyrae that changes brightness by a factor of 3 in a period of 13 days. Another star near Vega looks like two close stars in binoculars, in telescopes each is again a double stars. That’s Epsilon Lyrae. The jewel of this constellation needs a telescope to find between the two bottom stars of the parallelogram, the famous Ring Nebula.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A bi more stars than what will be seen in binoculars of the constellation Lyra. Created using Cartes du Ciel (Sky Charts).
In the chart above:
The star designated α is Vega
The star designated β is Beta Lyrae
The stars designated ε1 and ε1 is Epsilon Lyrae
The object designated M57 is the Ring Nebula
The Ring Nebula. Visually one cannot detect the color. It takes a large telescope to see the central star. Credit: Stellarium.
The Ring Nebula, AKA M57 by amateur astronomers, is a planetary nebula. The name planetary is a misnomer. Many of these objects look like the dim planets Uranus and Neptune. They are really stars like the sun, in their death throes puffing out their outer layers of gas at the end of their red giant stage. See below the latest image of the Ring Nebula I recently found on the Phil Plait’s Bad Astronomy Blog. It includes an explanation of what’s in the image.
Photo by NASA, ESA, and C. R. O’Dell (Vanderbilt University) and Robert Gendler
Click on the image to get lost in the Ring Nebula!
07/18/2014 – Ephemeris – Deneb is the brightest star of the Summer Triangle… Really
Ephemeris for Friday, July 18th. Today the sun will be up for 15 hours and 8 minutes, setting at 9:22. The moon, at last quarter today, will rise at 12:58 tomorrow morning. Tomorrow the sun will rise at 6:15.
At 11 this evening the bright star Deneb in Cygnus the swan will be moderately high in the east northeast. Deneb is the dimmest star of the summer triangle. Of the other stars of the triangle, Vega is nearly overhead, and Altair to the southeast. While Deneb’s apparent magnitude, or brightness as seen from Earth, makes it the dimmest of the three bright stars, Deneb has a vast distance of possibly 1,550 light years. If brought as close as Vega, Deneb would be several times brighter than Venus. For all this it is only 13-20 times the mass of the sun. It will have an extremely short life and will explode, go supernova, in perhaps a few million years. Closer to home, check out the Sun at Kingsley Heritage Days This Saturday and Sunday.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Deneb and the Northern Cross section of Cygnus the swan. Created using Stellarium.
One of my old photographs of Deneb and the North American Nebula digitized from a slide.
The North American Nebula, visible as a faint smudge in binoculars or the naked eye may be ionized and illuminated by Deneb. It’s distance appears to be comparable to that of Deneb.
You may note that previous postings about Deneb over the years have given different distances of Deneb. That just denotes how difficult it is to pin down its distance.
07/04/2014 – Ephemeris – Find patriotic red, white and blue stars
Ephemeris for Independence Day, Friday, July 4th. Today the sun will be up for 15 hours and 27 minutes, setting at 9:30. The moon, 1 day before first quarter, will set at 1:03 tomorrow morning. Tomorrow the sun will rise at 6:03.
On this patriotic day 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. Mars, the red planet, in the southwest, can be added even though it’s not technically a star. 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. 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, red, white and blue, is not related to the temperature in their cores. 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 white and blue stars for Independence Day at 11 p.m. on July 4, 2014. Created using Stellarium.
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.
Bob Moler's Ephemeris Blog 