Updated for the month of: May, 1996
A Dazzingly Bright, Crescent Venus 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 will reach its brightest position from Earth, as it races around the Sun on an inside track to the Earth's orbit, and comes ever closer to "catching up" with us. (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). Venus remains extremely bright all month. It is found about half up from the southwestern horizon as the Sun sets. It looks like a headlight from an airplane shining directly in your eye . . . you can't miss it!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 in May 1996, we see an even brighter "crescent Venus". So Venus gets brighter as it comes closer to Earth, even though the part that we see lit up is shrinking.
Look at Venus with a small telescope and you will see what looks like a crescent Moon!
M13 - The Fuzzy Mothball Crowded With Suns
High in the sky, and a bit east of directly overhead at midnight in May, 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 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 at at least 300,000 stars! (See time exposure amateur photos of M13 on the website of the Students for the Exploration and Development of Space.)
To find M13 around midnight in May, 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. 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. A dark, clear sky is needed to find the "keystone" and M13.
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? Do you want to see the familiar summer constellations of Scorpius and Sagittarius, the sparkling summer-time Milky Way crossing the sky, and the famous "Summer Triangle"? 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 August at 9:00 p.m.
Do the Days Seem to Be Getting Longer Faster?
If it seems like the day to day differences in the length of days is greater now than at some other times of the year, it's not your imagination. It is greater at this time of year. The day to day changes in length of day are greatest in Spring and Autumn and are least in summer and winter.
A Red Giant, 25 Times Bigger Than Our Sun!
The star Arcturus, in the constellation Bootes, appears half way up from the eastern horizon as dusk turns into darkness during May. It passes almost overhead around midnight. 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.
The Lion is Here!
As darkness falls during May, the constellation "Leo, the Lion" can be founed a bit west of overhead. It continues to move westward until it begins to set around 2:00 a.m.. The part of Leo that is most easily recognized is a sickle shape, or backward question mark, called "The Sickle". The bright star Regulus, known as the heart of the Lion, is at the bottom of the handle of the Sickle. Regulus is about 85 light years away. It is part of a double star system, two stars in each other's gravitational pull, rotating around each other. Its faint companion can be seen with a good pair of binoculars or a small telescope.If you look carefully and use your imagination you can actually see a lion. The curved part of the Sickle forms the head, looking toward the west. The bright star Regulus is the chest. The rest of the body, tail and hind leg stretch out toward the east.
Jupiter, a Late Night Treat
For those of you who go to bed late, during May,1996, the largest planet of them all, Jupiter, provides a treat in the middle night to early morning sky. Rising around 11:00 p.m., in the east, Jupiter is easily seen by 1:00 a.m. low in the southeast. It reaches its highest point, due south, around 4:00 a.m.. You can't miss it. It's very bright.Take a look through a telescope and you get an even better treat. Those four (or sometimes three or two) bright objects on either side of the giant planet in a linear alignment are Jupiter's four largest moons. What happened to the others when there are only three or two? They are not visible for a few hours because they are passing behind or in front of the planet.
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.
Giant Question Mark in Northern Sky
As darkness falls in May 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.
The Full MoonThe next full Moon occurs on the night of May 3, 1996.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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