This Week’s Sky at a Glance, 2023 October 14 – October 21
This Week’s Sky at a Glance, 2023 October 14 – October 21
The astronomical highlight for New Brunswick this week is a partial solar eclipse on Saturday afternoon from 1:33 to 3:25. At the peak, around 2:30, approximately 10% of the Sun’s surface area will be covered by the Moon. This is a prelude to a total solar eclipse occurring across the central half of the province on April 8, 2024. If any nature or astronomy clubs want a presentation on how to observe it safely, what you will see and where, and why they are so rare, please contact me.
Solar eclipses occur at new Moon, but since the Moon’s 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 orbital plane 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; which the one this weekend will be in parts of the United States, Mexico, Central and South Americas; occurs when the Moon is near apogee and its apparent width is smaller than that of the Sun.
Looking at the Sun without proper eye protection, even when it is mostly covered by the Moon, can cause temporary or permanent eye damage, and since the retina has no pain receptors you will not notice any damage for several hours. Proper protection is #14 or #13 welder’s glass, or approved eclipse viewers / glasses purchased 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.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 7:34 am and sunset will occur at 6:35 pm, giving 11 hours, 1 minute of daylight (7:38 am and 6:41 pm in Saint John). Next Saturday the Sun will rise at 7:44 am and set at 6:22 pm, giving 10 hours, 38 minutes of daylight (7:47 am and 6:29 pm in Saint John).
The Moon is new on Saturday afternoon, eclipsing up to 10% of the Sun between 1:33 and 3:25, and it is near the orange supergiant star Antares on Wednesday. Saturn is at its best for observing in late evening, still giving good views of its rings in a telescope. Rising about a half hour after sunset midweek, Jupiter offers telescopic views of its Red Spot storm around 10 pm Tuesday and near midnight on Thursday. Mercury is at superior conjunction on October 20, returning to the evening sky next month. Mars sets unseen in bright evening twilight, heading slowly toward solar conjunction in a month.
The Saint John Astronomy Club meets at the Rockwood Park Interpretation Centre at 7 pm this Saturday. There will be public observing of the partial solar eclipse at the Irving Nature Park in Saint John, and public observing at the park next Saturday evening for International Observe the Moon Night.