Most accurate from mid-northern latitudes of approximately 36-40 degrees, north;
(e.g. San Francisco, U.S.A. ** Madrid, Spain ** Tokyo, Japan)
Copyright (c) 1995 Pete Harris; **Back to Star Facts Home Page**
Updated for the month of: August, 1995
Shooting Star Show Hampered by Each August 12th the earth passes through the orbit of a long-ago disintegrated comet. The result is usually the best meteor shower of the year - the Perseid (PER-see-id) Meteor Shower. Although August 12th is the peak of the shower, the increased meteor activity continues from two or three days before to two or three days after August 12.
The best time to watch a meteor shower is after midnight local standard time - after 1:00 a.m. daylight time. (See August's Star Facts article, Meteor Showers and Shooting Stars After Midnight, and Why You Don't Have to Clean the Bugs Off the Rear Windshield, for explanation).The best way to watch is to lie down on a lawn chair or on the ground and look up for several minutes with just your unaided eye. During the peak of the Perseid shower, there are approximately 50 “shooting stars” visible per hour, or roughly one each minute. The overwhelming number of these meteors are only the size of a grain of sand or small pebble and burn up in the Earth’s atmosphere. The point at which we see their glowing streak across the sky is thought to be about 40 - 60 miles above the Earth. This shower is called Perseid because the “shooting stars” appear to all be coming from a point in the constellation Persius. There is actually no connection between the shower and Persius.
Unfortunately, this year’s observation of the Perseid shower will be hampered by the almost full moon that will be in the sky on August 12th. But you can give it a try anyway, while looking forward to next year when a half moon will already be setting around midnight on August 12th.
"The Teapot" - A Look Into
the Probably the best recognized and prettiest of the summer constellations is Sagittarius, better known as “the Teapot”. August evening hours are the best time to see it. From mid-northern latitudes it is found low in the southern sky. It clearly resembles an old teapot, tilted down toward the right, with its spout on the right side, its handle on the left side and a triangular top.
When we look at Sagittarius we are actually looking in the direction of the center of the Milky Way, the nucleus of our galaxy. This is the densest concentration of stars, gas and dust in the sky - it is an astronomical garden of rich star fields, beautiful nebulae, and sparkling star clusters. With binoculars or a low power eyepiece on a telescope, scan the areas above and on either side of the top of the Teapot. The glowing cloud-like areas are nebulae , places where new stars are being born from the gravitational collapse of interstellar dust and gas. The areas with tightly packed groupings of stars, known as open star clusters, are litters of young stars still “huddled” around one another before going off on their individual journeys through the galaxy. The dim fuzzy balls of light are ancient and distant groupings of thousands of stars, called globular star clusters, that date back to the beginnings of our galaxy, and travel in a ball-like shape in and out of the main disk of the Milky Way.
The "Summer Triangle" Marks
the Coming of Mid and Late SummerDuring evenings in mid and late summer, as the sun goes down, darkness begins to take over and the sounds of crickets begin, look overhead for the first stars that become visible. They will probably be 3 bright stars that form a distinctive triangular pattern. It is a landmark of summer called the Summer Triangle. The 3 stars which form this pattern are Vega, Deneb and Altair. Each of these stars is actually part of a different constellation. Vega is west-most of the three and is part of the small constellation Lyra. Deneb is north-most and is at the top of the “Northern Cross”, or officially called “Cygnus” (the Swan). Altair is south-most and part of the constellation Aquila.
Vega is not only the brightest of the 3 but it is the brightest of the summertime stars (don’t confuse it with the brighter planet Jupiter which is currently low in the southern sky, “passing through” Scorpius). Vega is “only” 26 light years away. It is so bright mostly because of its closeness. It is actually a relatively small star, about the size of our sun. Altair is even closer. It is “only” 17 light years away. Deneb, on the other hand, is a supergiant, with a diameter hundreds of times bigger than the other two. Deneb is 1800 light years away!. It is one of the furthest stars we can see with the unaided eye. Its size and brightness are so immense that even at its great distance, it appears to us almost as bright as Vega.
One more interesting fact about Vega. It has an important role in our future. In about 12,000 years the Earth will have changed its angle so that Vega will be virtually directly above our north pole. It will then be our North Star. (See June's Star Facts article, "There Will Come a Time When We No Longer Have a North Star" for further explanation)
Red Supergiant Sparkles in Summer SkyAntares is the brightest star in the constellation Scorpius - "the Scorpion". Scorpius clearly resembles the creature after which it is named (it also resembles the shape of a fish hook). In August, 1995, Scorpius can be found due south around 10:00 p. m. daylight savings time, with the curve of stars that form the scorpion's tail dipping down to the southern horizon.
Antares, which is the fairly bright reddish star toward the upper part of Scorpius, belongs to a rare class of stars called "red supergiants". It is a monster compared to our own sun, with a diameter 300 times as large (don't confuse it with the much brighter, bluer, smaller and closer planet Jupiter, which is currently "passing through" Scorpius, a little bit above and to the right of Antares). Antares is a distant star, 330 light years away from Earth (Jupiter is only about 56 light minutes away). The light photons from Antares that hit your eye in July, left the star 330 years ago.
Antares is a beautiful, reddish sparkling sight with the naked eye. With a pair of binoculars you can clearly see its unusual salmon color. Antares is part of a double star system (see July's Star Facts article, "Star Twins", for more about double stars), but its companion star is so close to it and so much dimmer that it takes a powerful telescope to see it.
The Moons of JupiterLike a string of pearls, the four largest moons of Jupiter appear in a diagonal line that crosses the giant planet. During July and August, 1995, as Jupiter continues to be close to its nearest position from Earth, these four large moons can be seen with a good pair of binoculars (see next item about Jupiter for description of how to find it in the sky). With a small telescope, the moons and planet make a spectacular sight.(See Calvin Hamilton's "Views of the Solar System" for more details about Jupiter's moons).
Not all of these moons are always visible. At various times only three or even two can be seen, as the moons circle behind or in front of the planet. Their positions change visibly from night to night, or even during a several hour period on the same night.
Jupiter at its Brightest & ClosestOn June 1st 1995 Jupiter, the 5th and largest planet in our solar system, came to opposition - the point in its orbit at which it was closest to Earth. At that time Jupiter, Earth and the Sun were all in a straight line. Jupiter remains relatively "close" to Earth in August and is very bright (the brightest object currently in the evening sky beside the moon ). Jupiter is a giant planet. A thousand Earths would fit inside of it. If it had been a bit bigger it would have been a sun, and our solar system would have had two suns.
Jupiter is currently found in the constellation Scorpius. In August it rises in the east during the afternoon,and travels a somewhat low path in the southern sky. It reaches its highest point, due south, around 9:30 p.m. daylight savings time. You can't miss it. It is very bright!
(click here to see the relative sizes of the planets - click on "back" to return to this page)
M6 & M7: Two Prominent Star ClustersTwo of the brightest "open" star clusters known are visible in August during early evening hours. Both are in the constellation Scorpius. They are known as M6 and M7. Both can be seen with a pair of binoculars or a small telescope. On very dark, clear nights, M7 can actually be seen with the naked eye. (See photo of M6 and photo of M7 from the University of Arizona SEDS web site).
To find these star clusters, around 9:30 - 10:00 p.m. follow the curving tail of Scorpius in the southern sky down toward the horizon, hooking left and back up a little to the two side-by-side stars at the top of the tail. From these two stars, scan a short distance to the left to see M7. From M7 scan a short distance up and to the right to see M6.
Open star clusters are groups of "young" stars within our galaxy, the Milky Way, that were created around the same time and are still relatively close to each other as they travel through space. The stars in M7 are about 260 million years old (our sun is about 4 billion years old) and are 800 light years away. M6 is 1,300 light years away. (For more information about open star clusters see Star Clusters from the University of Arizona SEDS web site).
The Disappearing Rings of SaturnAbout seven years ago the planet Saturn reached its greatest tilt toward the Earth so that a good deal of the surface of its spectacular rings showed to us. Even small telescopes revealed a magnificent view of the rings. Since then, its angle relative to us has been straightening. This year the angle of the rings becomes edge-on. Since the rings are believed to be only about 1 mile thick, the edge-on view will cause them to disappear from view. Although this is not good for ring watching, it is good for viewing the moons and surface of Saturn. In about seven years from now Saturn will again reach its greatest tilt toward Earth and the rings will once again present a spectacular sight.
During August, Saturn can be found between the constellations Aquarius and Pices. It rises in the east around 9:00 p.m. and travels a path across the southern sky, reaching its highest point due south around 1:00 a.m.
Full MoonThe next full moon occurs on August 10, 1995. The moon is full when it is on the opposite side of the Earth from the sun, so that the part of the moon that faces us also faces the sun. Therefore, at the time of a full moon, the moon rises in the east at the same time that the sun sets in the west.
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