School is out for the summer, but it is not yet officially summertime…not yet.
This year it will officially be summer on June 21, at about 10 in the morning CDT. Earth’s seasons change because of where the sun rises along the horizon, not the temperature outside. Imagine the Earth with two giant hula-hoops surrounding it that create an angle of 23.5 degrees where they intersect.
One hula-hoop would be horizontal, representing the equator. The second one would be above and below the horizon, representing the ecliptic, earth’s tilt of 23.5 degrees. Where the two intersect would be the determining point of the beginning of spring or autumn. On the first day of spring and the first day of autumn the Sun rises at exactly that point. From that point on, it appears to move either more northerly of east and west, slowly along the horizon, until the first day of summer, when it begins to retreat from that point farthest north from east.
The angled hoop represents the ecliptic, the imaginary path the Sun, Moon, and planets follow across the sky and it is never in the north part of the sky, so neither will those objects be visible anywhere but on an east to south to west track.
This week there should be plenty of time to stargaze, although dust in the air will prevent faint objects from being detected easily. Look for a dark area, away from city lights. I know those are becoming far too rare, but valley skies are darker than some other areas and some good constellation finding can happen.
Scorpius is rising from the east now and it is a good time to use that telescope to share M4, the gorgeous globular cluster that rests near Antares. Set your scope on Antares and look west. They both will fit in your field of view. Binoculars may enable you to locate emission nebulae in the area as well. Antares is a good jumping off point for exploring. Scorpius houses several other treasures, including the Northern Jewel Box open cluster and the Cat’s Paw nebula.
In the same region of sky, just above Scorpius, Ophiuchus stretches out and up much like a 1950’s electric percolator that every June bride hoped she would receive. A percolator was a sign you had reached that coveted marital state of wedded bliss with Mr. Right. The percolator in the sky represents medicine and physicians. Ophiuchus (Oh-FEE-uh-kus) was the mythical ancient physician who discovered the Secret of Life.
This week in the predawn sky Venus is lingering in the east-northeast; at dusk on Tuesday the New Moon will be in the west-northwest, sharing the sky with Mercury just a few degrees to the right of the Moon. Mars will be within Gemini to the left of the Moon. On Wednesday evening the three will form a line in Gemini before sunset.
By June 6, the Moon will be in the Crab constellation, Cancer. Get out your telescope or binoculars to look near the Moon to find the Beehive Cluster, M 44 within 4 degrees of the waxing crescent.
Fans of Jupiter are looking forward to watching the gas giant emerge into visibility after midnight. By 1:00 AM it will be high enough to explore as it brightens throughout the month to be bigger and brighter than it has been in the past five years. You may want to track those four Galilean Moons of Jupiter using the same method that great sky watcher did. Keeping a notebook and recording the motion of those four moons, Callisto, Io, Ganymede, and Europa could be an interesting summer project.
Until next week, do let some stars get in your eyes.
