This Week’s Sky at a Glance, August 19 – 26 ~ by Curt Nason
There is no doubt about the astronomical highlight for New Brunswick this week – a partial solar eclipse on Monday afternoon. Times will vary a little across the province but 2:30 to 5:00 pm will cover it. At the peak, between 3:45 and 3:50, approximately 50% of the Sun’s surface area will be covered by the Moon. This is our best solar eclipse since August 11, 1999, when more than 90% of the Sun was covered, and slightly better than the Christmas 2000 partial eclipse.
Solar eclipses occur at new Moon, but since the lunar orbit is tilted to Earth’s orbit by five degrees (ten times the Moon’s apparent diameter) it is usually above or below the Sun at that phase. For a period of a few weeks, twice a year, new Moon occurs when it is near to crossing Earth’s orbit and there will be a partial, annular or total eclipse somewhere on the planet. With a total eclipse, a rarity at any one location, the Moon’s shadow races across part of Earth on a path 100 to 200 kilometres wide. Locations outside of the shadow get a partial eclipse, with percent coverage decreasing with distance. An annular eclipse occurs when the Moon is near apogee and its apparent width is smaller than that of the Sun.
Staring at the Sun without proper eye protection can cause permanent eye damage, even blindness, and since the eye has no pain receptors you may not notice any damage for several hours. Proper protection is #14 welder’s glass or approved eclipse viewers / glasses from a reputable dealer. Note that these are not safe for use with binoculars and telescopes; other filters can be purchased for this purpose. A cheap and effective way to view the partial eclipse is to project the sunlight through a pinhole onto a white surface. Check the Internet for methods of doing this. Or, use Nature’s projection method by looking at the shadows of leaves, which often have tiny holes to project the Sun’s image.
The RASC and other organizations are hosting eclipse events in the province on Monday afternoon, with free eclipse viewers supplied by the RASC and views through filtered telescopes. Locations include the Irving Nature Park and Rockwood Park Bark Park in Saint John, UNB and Science East in Fredericton, Resurgo Place in Moncton, Riverview Community Centre, and Mount Allison University. Don’t take chances with your eyesight. Observe the eclipse but do it safely, and start thinking about where you will be on April 8, 2024 when the Moon’s shadow crosses the central half of New Brunswick.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 6:23 am and sunset will occur at 8:20 pm, giving 13 hours, 57 minutes of daylight (6:30 am and 8:24 pm in Saint John). Next Saturday the Sun will rise at 6:31 am and set at 8:08 pm, giving 13 hours, 37 minutes of daylight (6:38 am and 8:12 pm in Saint John).
The Moon is new on Monday afternoon, partially occulting a prominent star for a couple of hours, and it poses with Jupiter in evening twilight next Thursday and Friday. Jupiter sets by 10:00 pm next weekend and it is approaching Spica nightly. Saturn, in the southern sky in evening twilight, is the main telescopic attraction for the month. Venus, the bright Morning Star, moves from Gemini into Cancer late in the week. Mercury is at inferior conjunction on August 26, passing between us and the Sun.
Questions? Contact Curt Nason.