This Week’s Sky at a Glance, 2023 June 24 – July 1
This Week’s Sky at a Glance, 2023 June 24 – July 1
Friday is International Asteroid Day, an annual event sanctioned by the United Nations in 2016 to raise awareness of the potential hazards and benefits of asteroids. On June 30, 1908, a 60-metre wide stony asteroid (or a somewhat larger comet) exploded at an altitude of eight kilometres over the sparsely populated region of the Tunguska River in Siberia, about 700 km northwest of the northern tip of Lake Baikal. At 7:17 am local time a tongue of flame split the sky, followed by loud bangs, ground-shaking tremors and a hot wind of hurricane force. A seismic event was recorded 900 km south, and a microbarograph in England recorded a pressure event five hours later and again a day after that.
Expeditions were led two decades later by Leonid (great name for a meteorite hunter) Kulik to locate and interview eye witnesses and to locate the crater and meteorites. No crater or meteorites were found, but there was an area of 2100 square kilometres where trees were blown down in a radial pattern. Those trees in the midst of the destruction remained standing with their limbs stripped.
Ceres, by far the largest asteroid, was reclassified as a dwarf planet in 2006 at the same time as Pluto. To celebrate Asteroid Day, try to locate an asteroid in the night sky. It will look like a faint star in a telescope, and a good star map will be needed to distinguish one from the background stars. The traditional method is to carefully sketch the star field and return the next clear evening to see which one has changed position relative to the others. The Heavens-Above website has wide-field and detailed inset maps for the brightest asteroids, and Ceres is the brightest one in the evening sky. The inset map is about the size of the field of view seen with common binoculars.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 5:28 am and sunset will occur at 9:14 pm, giving 15 hours, 46 minutes of daylight (5:37 am and 9:16 pm in Saint John). Next Saturday the Sun will rise at 5:31 am and set at 9:14 pm, giving 15 hours, 43 minutes of daylight (5:40 am and 9:15 pm in Saint John).
The Moon is at first quarter on Monday, providing great views through a telescope or binoculars all week. Venus and Mars are within the same binocular view all week, in quasi-conjunction since Venus will not pass Mars. After gaining on the red planet throughout spring it will drop out of the chase and start heading sunward. Saturn is now moving westward against the background stars, putting more distance between itself and bright Jupiter in the morning sky. By the end of the week Saturn will be rising around midnight. Mercury is too close to the Sun for viewing and it reaches superior conjunction next weekend.
On Sunday evening at 8 pm, tune in to the Sunday Night Astronomy Show via the Facebook page or YouTube channel of Astronomy by the Bay.
Friday is International Asteroid Day, an annual event sanctioned by the United Nations in 2016 to raise awareness of the potential hazards and benefits of asteroids. On June 30, 1908, a 60-metre wide stony asteroid (or a somewhat larger comet) exploded at an altitude of eight kilometres over the sparsely populated region of the Tunguska River in Siberia, about 700 km northwest of the northern tip of Lake Baikal. At 7:17 am local time a tongue of flame split the sky, followed by loud bangs, ground-shaking tremors and a hot wind of hurricane force. A seismic event was recorded 900 km south, and a microbarograph in England recorded a pressure event five hours later and again a day after that.
Expeditions were led two decades later by Leonid (great name for a meteorite hunter) Kulik to locate and interview eye witnesses and to locate the crater and meteorites. No crater or meteorites were found, but there was an area of 2100 square kilometres where trees were blown down in a radial pattern. Those trees in the midst of the destruction remained standing with their limbs stripped.
Ceres, by far the largest asteroid, was reclassified as a dwarf planet in 2006 at the same time as Pluto. To celebrate Asteroid Day, try to locate an asteroid in the night sky. It will look like a faint star in a telescope, and a good star map will be needed to distinguish one from the background stars. The traditional method is to carefully sketch the star field and return the next clear evening to see which one has changed position relative to the others. The Heavens-Above website has wide-field and detailed inset maps for the brightest asteroids, and Ceres is the brightest one in the evening sky. The inset map is about the size of the field of view seen with common binoculars.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 5:28 am and sunset will occur at 9:14 pm, giving 15 hours, 46 minutes of daylight (5:37 am and 9:16 pm in Saint John). Next Saturday the Sun will rise at 5:31 am and set at 9:14 pm, giving 15 hours, 43 minutes of daylight (5:40 am and 9:15 pm in Saint John).
The Moon is at first quarter on Monday, providing great views through a telescope or binoculars all week. Venus and Mars are within the same binocular view all week, in quasi-conjunction since Venus will not pass Mars. After gaining on the red planet throughout spring it will drop out of the chase and start heading sunward. Saturn is now moving westward against the background stars, putting more distance between itself and bright Jupiter in the morning sky. By the end of the week Saturn will be rising around midnight. Mercury is too close to the Sun for viewing and it reaches superior conjunction next weekend.
On Sunday evening at 8 pm, tune in to the Sunday Night Astronomy Show via the Facebook page or YouTube channel of Astronomy by the Bay.
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