Summer Skies Invite Observers to Look Up
By Rod Kennedy
June is a fine month to be outdoors. June has been important to skywatchers long before our modern Gregorian calendar came into existence. This importance is due to one special day: the Summer Solstice. Ancient peoples celebrated the longest day of the year with feasts and ceremonies. The Summer Solstice is the point when the northern hemisphere is tilted toward the sun and the sun reaches its northern most point in the sky. From that day forward the days get shorter as the sun moves slowly south. In our modern calendar the Summer Solstice occurs on June 21st which means that sky watchers in Wyoming will have to stay up late to enjoy the sky to its fullest.
If you’re willing to stay up past 9:00 pm the June sky holds a wealth of interesting sights. In the west we find both Mars and Saturn huddled near the star Regulus in Leo the Lion. As June progresses Mars will slowly draw closer to both Regulus and Saturn. This close proximity of planets is called a planetary conjunction. The real show will occur in July when both planets are less than one degree from each other; but for June we can watch the planets get closer. We can find Mars and Saturn by using the moon as a guide. On the evening of June 7 the crescent moon will be less than one degree below the red planet. Telescope users can catch both moon and Mars in one field of view by using a wide field, low magnification eyepiece. The next night, June 8 a slightly larger crescent moon will be just below the star Regulus, a little below and to the right of Saturn. Again, telescope users should use eyepieces of low magnification with wide field of view. For observers more interested in stars June presents a wide range of stars with varying temperatures and colors.
Using the arc of the Big Dipper’s handle as a guide look almost directly overhead for the star Arcturus in Bootes the herdsman. Arcturus is an orange star which means it is much cooler than our own star the sun. Arcturus is also classified as a giant star, which means it is much larger than our sun and is therefore reaching the end of its life cycle. If you keep moving along the curve from Arcturus toward the south western horizon you will find Spica in Virgo the Maiden. Unlike Arcturus, Spica is a blue main sequence star. Spica is blue because it is much hotter than our sun. A main sequence star is right in the middle of its life cycle. Yet because Spica burns so hot its life will be far shorter than that of our sun, only a few hundred million years as compared to several billion years for our sun.
Looking southeast from Spica we find Antares in Scorpius the Scorpion. Antares is a red super-giant star. This star is even cooler than Arcturus and far larger; so large that if we put it in our own solar system it would occupy space beyond the orbit of Jupiter. Antares is also reaching the end of its life cycle and may some day end as a super nova. Looking east we find Vega in Lyra the harp rising above the horizon. Vega is a white main sequence star, hotter than Arcturus but not as hot or large as Spica.
Skywatching in June is a fun adventure if you’re willing to stay up late or venture out to dark skies. Telescopes or binoculars can enhance the adventure but they are by no means the only way to enjoy the sky. Just looking up and learning the names and positions of the stars and constellations is a rewarding activity that can be extended year round.
