Some say that autumn is the best time of year in West Michigan. If so, then the good times officially roll on Monday, Sept. 22 at 11:44 AM EDT. At this instant the sun will cross the celestial equator — earth’s equator projected out onto the sky — heading from north to south, marking the astronomical beginning of autumn.
Astronomers call Monday the autumnal equinox. Equinox means roughly “equal night”, which isn’t quite the case on Monday. The sun will rise on Monday at 7:34 AM and set at 7:41, making the day about seven minutes longer than the night. It isn’t until Thurs., Sept. 25 that the sun sets exactly twelve hours after it rises. On Monday, the day is a bit longer than the night because the sun is a disk, and sun rise and set are measured from the very top part of the sun. Anyway, it’s just a matter of minutes.
But on the equinox one thing is true: the sun rises due east and sets due west for every observer on earth. For us in West Michigan, where most of the roads are laid out east-west and north-south like the rulings on a sheet of graph paper, the equinox sun rise and set can be blinding on the commute to and from work. Take an extra pair of sunglasses with you in the car.
More and more darkness gives us more and more time to wonder at the night sky. One nice thing to look for right now, shortly after sunset, is a cluster of planets in the west over the lake. Venus, Mars and Mercury are presently clustered in a relatively tight little bundle that sets in the west just thirty minutes or so after the sun. Venus stands out easily because she is so wonderfully bright, but to see her companions you might want to bring along a pair of binoculars.
If you can’t get out to see the trio of planets next week, you’ll still have opportunities to see Venus. As fall wears on, goddess of love will slide higher and higher above the horizon in the west after sunset, growing brighter and brighter with each passing day.
Jupiter continues to hold his place in the sky in the constellation Sagittarius above the horizon in the south. But as the days go by, he’ll slip more and more to the west at sunset, to be out of view by early winter.
At dawn we can look forward to seeing more and more of mighty Saturn. Right now, the ringed marvel rises just about a sunrise, but as the days grow shorter, he will rise earlier and earlier. By early December, Saturn will be high above the horizon in the southeast before sunrise.
Saturn’s rings are normally an ideal target for testing out your goto telescope, but this year and into next, the relatively razor-thin rings are oriented edge-on to earth, so we cannot get a good view of them.
Mercury will make a brief appearance in the east before sunrise in late October. Catch him if you can.
All the while, Orion and his cohorts — Taurus the bull, Gemini the twins, and Orion’s hunting dog Canis Major — are rising earlier and earlier to take the familiar places high in the cold sky by the beginning of winter.
Winter will be officially upon us on Dec. 21 at 7:04 EST. And while the weather will after that grow steadily colder and snowier, the nights will actually begin to grow shorter as we make our way back around to the spring rains and warm summer nights.
