"Tonight's Sky" is written by retired planetarium director Dave Leake and reprinted with his permission. See Dave Leake's "Prairie Skies" column in the Champaign-Urbana News-Gazette each Monday morning. Dave Leake's preview of 2019 sky events can be found here.
We begin September with a beautiful crescent Moon in the southwest. It will move eastward each night until it is one quarter of the way around our Earth on Thursday, hence a “first quarter Moon.” On this night, it makes a triangle with Jupiter, to the left, and the star Antares, below the Moon. Take a peek at it during halftime of the Bears/Packers football game! A thicker Moon is to the right of Saturn on Saturday night. It’s a busy weekend for the CU Astronomical Society. Check out the Sun through solar telescopes at the Urbana’s farmer’s market Saturday morning, then enjoy views of the planets at a free observatory open house that night. All weather permitting, of course (cuas.org).
Join CU Astronomical Society members for a presentation by Matias Carrasco from NCSA to talk about the Dark Energy Survey (Thursday, 7pm, planetarium). Thursday is also the registration deadline for the Illinois Dark Sky Star Party near Springfield (http://sas-sky.org/2019-idssp). The event occurs the last week of September. Friday’s full Moon is the Harvest Moon. Many think the Harvest Moon is larger and brighter than most but this year, the Moon is actually a little farther away than usual. The Harvest Moon effect has to do with rise times. The Moon rises an average of 50 minutes later each night but, near the autumn equinox, this lag time is at a minimum, thus providing more light for the harvest.
The Staerkel Planetarium has resumed its Friday/Saturday programming schedule for September. The show line-up features a live tour of the evening sky in “Prairie Skies,” a virtual trip inside our closest star in “Solar Superstorms”, and “Solar System Safari” for the kids. See their web site for a full schedule and ticket information. This Friday, CU Astronomical Society telescopes visit the meadow at Allerton Park for the Prairie Sky Concert Series (weather permitting). Look for the Big Dipper in the northwest, actually looking like a dipper shape. The curve of the dipper’s handle will lead you to the star Arcturus in the west. Arcturus is an orange star and the 4th brightest in the sky.
Venus passed behind the Sun about a month ago and is now emerging into our evening sky, but its rise is very slow. Look right after sunset a little to the left of due west but don’t mistake it for the star Arcturus, placed higher in the sky. If you can’t see it this week, keep looking. When will you first see it? Autumn officially began this morning at 2:50am as our Sun was situated above Earth’s equator. We’ll have roughly equal amounts of day and night. This Friday CU Astronomical Society telescopes visit the Middle Fork River Forest Preserve to observe dark skies from the North Waterfowl Management Area, north of the campground. Join us!
September 30 – October 6
Friday night at the planetarium, we welcome our first speakers in the Kaler Science Lecture Series. Parkland students will present on their summer research projects. Admission is $2 at the door. Saturday’s first quarter Moon means another open house at the CUAS Observatory (cuas.org). Join us for a look at Saturn and Moon craters. Call 217-351-2567 if weather is uncertain. Saturday is also International Observe-the-Moon Night, an annual event to celebrate lunar science and exploration. Get those binoculars out of the closet and check out our closest neighbor in space, especially along the shadow line (“terminator”) dividing light from dark on the Moon’s face. Look for the dark “Maria” and bright dots (mountains catching sunlight) on the dark portion.