WHAT'S UP there DOC

- a guide to current sights and events in the evening sky

Updated for the month of: June, 1996

The Scorpion Climbs Highest at Midnight Hour

Rising in the southeast around 9:00 pm and taking a very low path across the southern sky is the constellation Scorpius, "the Scorpion". From mid-northern latitudes you can't see all of the Scorpion until it rises to its highest point above the southern horizon, which in June accurs around midnight. Scorpius clearly resembles the creature after which it was named ( or a fish hook), with the curving path of stars that form the Scorpion's tail dipping down and left to the southern horizon, then curving back up.

In Greek mythology, Scorpius is named after the legendary scorpion that killed Orion. As a result, Orion and Scorpius were placed as far apart in the heavens as possible to avoid further trouble between them.

When you look at Scorpius you are looking in the direction of the very center of our galaxy, the Milky Way. Here you will find the densest concentration of stars to be found in the sky. Sweep the area with binoculars or a small telescope and enjoy the beautiful star fields, nebulae, and clusters.



Jupiter Nears its Brightest & Closest Point

On July 4, 1996, the largest planet in our solar system, Jupiter, will come to opposition - the point in its orbit at which the Sun, the Earth, and Jupiter are in a straight line, and Earth and Jupiter are closest to each other. Therefore this summer is a particularly good time to look at Jupiter. Jupiter is currently found in the constellation Sagittarius. In June, 1996, it rises in the southeast around 11:00 pm, Daylight Savings Time, travels a somewhat low path across the southern sky, and reaches its highest point, about 30 degrees above the horizon, due south around 2:00 am. Other than the Moon and Venus (which sets shortly after sunset in June), Jupiter is the brightest object in the night sky - you can't miss it.

Take a look through even a small telescope and you get a better treat. Like a string of pearls, the four largest moons of Jupiter appear in a diagonal line that crosses the giant planet. Their names are Io, Europa, Ganymede, and Callisto in order of increasing distance from Jupiter. 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, even eclipsing each other at times. Their positions change visibly from night to night, or even during a several hour period on the same night. Look closely at the planet itself with a telescope and, under good conditions, you can see one or two of the dark bands that go around Jupiter like a belt.

Jupiter is a giant gas planet. About one hundred Earths would fit inside of it. Jupiter is so big, it was almost a small sun. If it had been big enough to be a sun ( that is, if it had enough mass to support thermo-nuclear fusion), our solar system would have two suns . We would sometimes see them both in the sky at the same time. At other times they would alternate so that as one was setting the other would rise, resulting in no night. (See Star Facts article for January, 1996, "How and Where Stars are Born" for more details about what causes a sun to turn on.)

As you look at Jupiter and it's four largest moons with a telescope, imagine Galileo's amazement about 300 years ago when he used the first astronomical telescope to look at Jupiter, and became the first human being to see the moons of another planet. You can repeat that same amazement for yourself tonite! (See Calvin Hamilton's "Views From the Solar System" for more information about and pictures of Jupiter and its moons).



A Bright, Crescent Venus Right After Sunset!

Since January 1996, the planet Venus has presented an increasingly spectacular sight in the southwestern sky after sunset. Other than the Sun and Moon, Venus is the brightest object in the sky. On May 4, 1996, Venus reached its brightest position from Earth, as it races around the Sun on an inside track to the Earth's orbit, and finally "catches up" with us on June 10, 1996 (See "Solar System Live" website to see current relative positions of the planets, click on "inner planets", blue circle is Earth, white circle is Venus). During the first few days in June, you can still see a very bright Venus low in the west right after sunset. Later in the month, Venus becomes visible in the morning sky, shortly before sunrise in the east.

Because Venus, our next door neighbor in space, is closer to the Sun than Earth is, we see it going through phases that are similar to the Moon's phases. When it is on the opposite side of the Sun from Earth we see it far away but full-face, a "full Venus". When there is a 90 degree angle between Earth, Sun, and Venus, we see a brighter "half Venus" as only the half that faces the Sun is lit up from our angle. As Venus catches up to Earth in its orbit and comes close to lapping us on its inside track, as is the case now, we see an even brighter "crescent Venus".

Look now with a telescope and you will see an amazing sight - a thin crescent Venus!



M13 - The Fuzzy Mothball Crowded With Suns

High in the sky, and a bit east of directly overhead at midnight in June, is the finest globular star cluster visible from mid northern latitudes. It is called M13, and it is in the constellation Hercules.

Globular star clusters are ancient groupings of stars believed to have formed early in the history of our galaxy. They contain some of the oldest stars known, ten to twelve billion years old. That is more than twice the age of our Sun. They are made up of hundreds of thousands of stars packed together much more closely than stars normally are, into a sperical shape. Interestingly, though globular star clusters are considered part of our galaxy, most of them lie outside the plane of the main disk of stars that form the Milky Way. They lie mostly above or below the central core of the galaxy, forming a halo-like pattern around the galactic nucleus.

M13 appears with the naked eye or binoculars as a soft glowing ball of light, a fuzzy mothball. It takes a reflector telescope with an 8 to 10 inch mirror to begin resolving some of the individual stars around the edge of the cluster. Most estimates of the number of stars in M13 put it at between 300,000 and one million stars! (See time exposure amateur photos of M13 on the website of the Students for the Exploration and Development of Space.)

To find M13 between the period of about 10:00 pm to midnight in June, face south and look a bit east of directly overhead. Locate a keystone pattern formed by four stars. This is a square-like shape, with the top two stars being a little wider apart than the bottom two stars. Unless it is a very dark location, you almost need a pair of binoculars to find this keystone shape. The "keystone" is the center of the constellation Hercules. M13 is about 1/3 of the way down on the imaginary line connecting the top right star to the bottom right star of the keystone.



M6 & M7: Two Prominent Star Clusters

Two of the brightest "open" star clusters known are visible in June after about midnight. 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, 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.



Night Owls Get a Preview of Next Season's Stars

Do you want to get a preview of the prime time stars of the next season? If you want to see what the evening sky will look like three months from now, look now, but look six hours later! Look at the sky at 3:00 a.m. and you will get a preview of what will be visible in September at 9:00 p.m. See Star Facts article for June, 1996, "See a Preview of Next Season's Prime Time Stars Now!" for explanation of this phenomenon.



A Red Giant, 25 Times Bigger Than Our Sun!

The star Arcturus, in the constellation Bootes, appears directly overhead as dusk turns into darkness during June. It continues westward during the night, setting around 3:00 am. The easiest way to find it is to follow the curve of the handle of the Big Dipper, backward from the bowl, and "arc to Arcturus".

Arcturus is a red giant, a cooling sun nearing its death. It is the third brightest star in the sky. In its bloated last stages of existence Arcturus has swollen to a diameter of about 25 times the size of our Sun's. It lies about 36 light years away. Its orange-red color is distinct with binoculars.



Giant Question Mark in Northern Sky
Can Save Your Life

As darkness falls in June the Big Dipper appears as a tipped over question mark in the northern sky. The Big Dipper is the most recognized shape in the sky. From most of the northern half of the Earth it never sets! It just goes around the North Star, making one giant circle each 24 hours. Even though the Big Dipper is one of the largest star shapes in the sky, it is only part of a still larger constellation called Ursa Major, or Big Bear (good luck seeing a bear - the people who named it must have been smoking some of that funny stuff). A recognizable shape, such as the Big Dipper, that is part of one or more constellations is called an "asterism".

The Big Dipper can save your life if you are ever lost at sea or in a wilderness area, by providing a way to determine which direction is north. The two stars at the dipper end (not the handle) are called the "pointers". They point to Polaris, the North Star. If you follow an imaginary line extending from the pointers 3 fist widths across the sky (the width of your fist with arm extended) in the direction of the open side of the dipper, you come to the North Star. It is not a bright star, but it is the brightest in that part of the sky.



Two Full Moons in June - Once in a Full Moon!

In June, 1996, the United States will have two full moons. The first one occurs after sunset on June 1. The second one occurs officially on June 30, at 11:58 pm, Eastern Daylight Time, just squeezing in before the end of the month. Two full moons in the same month occurs on average about once every 2.7 years. The second full moon in a month is called a "Blue Moon" - hence the saying that a rare event occurs "once in a Blue Moon".

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 about the same time that the Sun sets in the west.

The best times to view the moon with binoculars or telescope is definitely not around the times of a full Moon. It is during the times when the moon is in the crescent to half moon shape. It is at this time that the shadows on the Moon are the longest, making the craters and mountains on the Moon more visible and three dimensional. The best place to look is around the areas where the light and dark sides of the Moon meet. This dividing line, called the "terminator", is where sunset or sunrise is occurring on the Moon, and shadows are the longest.

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Send suggestions, astronomy tips, corrections or comments to Pete Harris
via e-mail at odyssey@ccnet.com. Pete is also the creator of the website
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