StarWatch for the greater Lehigh Valley

JULY  2000


201   JULY 2, 2000:     Summer: Looking North
For the next five weeks we’ll be taking a tour of the summer sky, starting in the north and moving clockwise to the east, south, and the west. On the fifth week we will view the sky seen overhead. Each week’s StarWatch article will be accompanied by a map which can be downloaded from the ASD Planetarium’s web site. During July there will be two new moons, one on the first and other on the 31st. Each moon will have a partial solar eclipse associated with it, but neither will be visible from the Lehigh Valley. On the 16th, the night of full moon, Hawaii, the South Pacific, and eastern Asia will be treated to one of the longest lunar eclipses possible. See last week’s StarWatch. Early July at 10:00 p.m. finds the Big Dipper in the NE about mid-sky, cup down, handle up. Polaris, the North Star, can be located by tracing a straight line to the right from the two lowest stars of the Big Dipper’s cup. Virtually stationary, Polaris is now the lowest star of the Little Dipper which stands cup up and handle down. Winding its way around the Little Dipper is Draco, the Dragon, in its best position for the year. Its extremely long tail arcs around the Little Dipper to a jumble of stars which defines its small body. The trick is to find the head, four fairly bright stars that form a trapezoidal figure near the sky’s zenith. You could also imagine Draco looking like a turtle. The shell is represented by the Dragon’s tail. The neck of the Dragon becomes the turtle’s neck stretched outward and upward from the shell. Between the handle of the Big Dipper and the cup of the Little Dipper can be found the star, Thuban. It was the pole star around the time of the construction of the Great Pyramids at Giza, Egypt, about 2650 BC.

Looking North

202   JULY 9, 2000:     Summer: Looking East
We continue our tour of the summer sky by looking east at 10:00 p.m. See the July 2000 StarWatch at the ASD web site listed below for a star map. Presently at the zenith, Hercules is faintly visible from suburban and rural skies. He is best found by locating the head of Draco (see last week’s StarWatch) and the brightest star in the east, Vega, which also forms the top of the Great Summer Triangle. Hercules lies on his side with the most prominent part of his body, "the Keystone" representing his torso. A little towards the left of the two top stars of the Keystone is M13, one of the showpieces of the heavens. Easily visible with binoculars as a fuzzy circular glow, it is, in reality, a globular cluster, an aggregate of over 200,000 stars, almost like a miniature galaxy, but part of the much larger Milky Way system, our 400 billion star galaxy in which we live. Looking at blue white Vega with binoculars, you’ll easily notice the parallelogram of four stars off to the right and below. Nearly between the two stars farthest to the right can be found the ring nebula, M57. You’ll need a telescope to see it, but it looks almost like a perfect greenish smoke ring. It resulted when a star similar to our sun ejected mass as it was dying. The ring, until recently, was thought to represent a sphere of glowing material around the star; but now astronomers believe it is a ring-like structure. The holes are formed by invisible matter being blown away from the dying star. Finally, one binocular field to the left of Deneb, the faintest of the three Summer Triangle stars, is a brighter patch of Milky way called the North American Nebula. You might have guessed that photographs reveal it to look much like the continent on which we live.

Looking East

203   JULY 16, 2000:     Summer: Looking South
Because tonight’s moon is full, you may want to wait several days before going out and attempting the southern sky. A map for this week’s stars can be found on the ASD Planetarium’s web site noted below. Mid-July, around 10 p.m. represents one of the best times of the year for catching the southern constellations of Sagittarius and Scorpius. These star figures can be illusive because during summer, the full moon is low in the sky. Trees and buildings often obscure part or all of these sky figures. Make sure your southern horizon is good, and the night is clear and moonless. Low and due south will be red Antares, the brightest star of the Scorpion. What makes the Scorpion so distinctive is its curved body and tail, complete with a stinger. It serves as a great reminder to be ever vigilant for these tiny creatures when observing in drier climes. To the Scorpion’s left is Sagittarius, the Centaur. If you see the back end of a horse and a bow and arrow being held by the body of a man, you might simply consider having yourself committed. However, if you see what looks like a "Teapot," complete with top, handle, and spout, you are on the right track. Sagittarius, the Teapot, is a great reminder to bring along a hot drink with you, even if you are observing in the summertime. Clear nights are often cool nights. The Earth’s rotation will cause the Teapot to tip forward spilling its warm tea over the SW horizon near dawn. Finally, don’t forget Ophiuchus, the Serpent Bearer. It will look like a tilted house below Hercules. Rising from the right of Ophiuchus will be Serpens, the Serpent, which Ophiuchus is battling. A glitter of faint stars marks the Serpent’s head which can only be glimpsed from suburban areas on the best of summer evenings.

Looking South

204   JULY 23, 2000:     Summer: Looking West
As we circle the sky this July, we focus this week on the west. A sky map showing the stars and constellations found in the west for 10:00 p.m. EDT can be found by following the appropriate StarWatch links on the ASD Planetarium’s home page given below. Even in late July, it’s still possible to view the stars of spring. Facing west, the Big Dipper is now to your right and much lower. Follow the handle’s arc to reddish Arcturus, of Bootes, the Herdsman or Bear Driver. Then continue onward to spike Spica, the principal star of Virgo, the Virgin. Don’t expect to see Virgo. She looks like a lizard lady in a sleeping bag. Even from the darkest skies out West, there are problems in seeing her. But blue-white Spica is always a treat. Likewise, Bootes, a man, looks more like a kite. Unlike Virgo, this figure can be readily seen from suburban skies. Above "Boots," as he is affectionately known by many amateurs, lies a semi-circular star group called Corona Borealis, the Northern Crown, or the Boomerang if you are Australian. It doesn’t take much of an imagination, just a dark clear night, to see how appropriate these two names are in describing the seven jewels which create its form. Returning to the Big Dipper, the top luminary of the two pointer stars which are farthest to the right, is called Dubhe. Below is Merak. The seven stars can be recited by remembering their initials. Starting with Dubhe they are D-M, P-M, A-M, A. Dubhe (DUE-be), Merak (ME-rack), Phecda (FEC-da), Megrez (MEG-rez), Alioth (AL-e-oath, Mizar (MY-zar), and Alkaid (AL-kade). You’ll have plenty of time to commit them to memory, for the Dipper will hold its shape fairly well for the next 25-50,000 years.

Looking West

205   JULY 30, 2000:     Summer: Looking Overhead
Our circling of the summer sky will be completed this week by including the stars which are directly overhead. A star map can be found at the ASD Planetarium’s web site given below. Observe at 10:00 p.m. EDT. Looking overhead and facing south, you’ll notice the three bright stars of the Summer Triangle to your left. The brightest of this triad is Vega. It will be highest in the sky. If the night is hazy, these stars may be the only ones visible from an urban location. To the right, the handle and cup of the Big Dipper will appear much lower in the sky. Bright Arcturus can still be found by following the arc of the Dipper’s handle westward. But it won’t be around for long. For observers in the suburbs, look north and try finding Hercules, the Strongman, which is virtually overhead at 10 p.m. Its body, also called the Keystone, is composed of stars which can easily be seen from suburban locales. Hercules’ legs will be pointed southward, while his arms will be outstretched towards the north. Hercules has no head. But don’t worry, just a little imagination will put everything into perspective. The small quadrilateral of Draco’s head will be next to Hercules’ head. Mythologically, they are not the best of friends, for it was Hercules that stole the Golden Apples of the Hesperades, Hera’s wedding gift to Zeus. Draco guarded these golden apples. Knowing that he was unable to defeat the Dragon in battle, Hercules enlisted the help of Draco’s good but dull-witted friend, Atlas, to do the dirty work. The ploy worked, but Hera found out and punished the Dragon by tossing him into the sky and placing him close to the Pole Star so he would be ever visible, and therefore unable to rest and refresh himself.

Looking Overhead

July Star Map

July Moon Phase Calendar