Click here for Dave's preview of sky events in 2016.
For: April 18-24
The second installment of “Astronomy on Tap” will be this Thursday evening (6-7pm) at Pizza M in Urbana. This has been very popular and it’s tough to get a seat! You don’t need a seat outside! Look above Jupiter for the constellation of Leo, the Lion. The head of our lion is a backwards question mark shape, marked at the bottom by the star Regulus. Regulus means “the little king.” It’s the twenty-first brightest star in the sky. Do these stars look like a lion? Not really, but in ancient times the Sun was in front of these stars during the summer solstice. With the Sun so high in the sky at noon, ancient skywatchers wanted to give this spot a regal name.
For: April 25 – May 1
Just before midnight tonight, look for the waning gibbous Moon rising just above and left of Mars. It is a good time to start watching Mars as the Earth will be close to Mars next month, an event that happens every 26 months. Mars normally moves west to east against the background stars but, during this time, Mars will appear to stop and go backwards. If you find a map of the constellation Scorpius, you can chart this. Mark the position of Mars on the map once every five days or so. This backwards motion is an illusion. You can see the same thing when you pass a slower car on the highway. They will appear to go backwards as you pass them.
For: May 2-8
Thursday brings the annual Delta Aquarid meteor shower when the Earth crosses the trail of Halley’s Comet. See how many “shooting stars” you can find in the pre-dawn sky. Saturday, if skies are clear, you are all invited to the Middle Fork Forest Preserve, northeast of Rantoul, for a “starwatch.” We’ll begin with a short program at the activity center at about 8pm and then look through telescopes afterwards. Jupiter will already be high in the sky, nearly due south. Mars will rise at about 10pm with Saturn following about a half hour later. And it’s free! Call 351-2567 if the weather threatens. We should get great views of all three planets under some of the darkest skies in the county!
For: May 9-15
If you are reading this Monday morning, a transit of Mercury is happening right now! A transit is when an inner planet treks across the face of the Sun. The last transit of Mercury occurred in 2006. This event begins at 6:12am and last until 1:42pm today. Weather permitting we will have a few telescopes at the planetarium equipped with appropriate filters beginning at 9am. Sunglasses don’t provide adequate protection and eclipses glasses won’t give you enough magnification. Saturday is a big day! We’ll be at “Market at the Square” looking at the Sun from 8-noon, then have an observatory open house that evening (cuas.org). It is also “National Astronomy Day” and the 30th anniversary of our astro club.
For: May 16-22
Saturday is the long-awaited opposition of Mars. Mars is currently “opposite” the Sun and therefore rises at sunset. Mars is technically closest to our Earth on the 30th but anytime in the next couple of weeks is a wonderful time to see this planet. Oppositions of Mars occur every 26 months. Look for Mars in the southeast. It will be one of the brightest objects in that part of the sky, to the right of the Moon. Saturday is also the date of the Full Moon and May’s moon is called the “Full Flower Moon” or the “Milk Moon.” Sunday evening the nearly Full Moon rises in the southeast to the left of the planet Saturn.
For: May 23-29
As the Sun sets this week, let’s look for some color in the sky. Stars do come in different colors but usually no one looks at them long enough to notice. Low in the northwest is Capella, a yellowish star. Due south, about four fists high, is Spica, a bluish star. Above it is Arcturus which comes to us with an orange hue. Low in the southeast is Antares, which is noticeably red. Star colors show their temperatures. Red stars have surface temperatures in the 3000K range. Still how enough to burn you pretty well! The temperatures then rise until we get to the blue stars which can go up to 40,000K!! The stars are given a star class based on their temperatures. The classes are O, B, A, F, G, K, M, L and T.
For: May 30-June 5
Tonight Mars is closest to our Earth at 46.8 million miles. Of course anything that is close looks bright to us and large through a telescope. The orbit of the Earth around the Sun is nearly a perfect circle, but Mars’ orbit is far from perfect. Therefore opposition distances vary. In 2003 Mars was 34.6 million miles from us. This is also when that post on Facebook started, stating Mars would appear in the sky the size of the full Moon! That won’t happen. In 2012, Mars got to within 62.6 million miles. In another 26 months (July of 2018), we’ll be 35.8 million miles from our neighbor in space. Get that telescope out of the closet and check it out!
See Dave Leake's "Prairie Skies" column in the Champaign-Urbana News-Gazette each Monday morning.