This Week’s Sky at a Glance, 2022 May 14 – 21 ~by Curt Nason
The Moon takes centre stage this week with perhaps the most significant stargazing event of the year, all the stages of a total lunar eclipse from Sunday evening into early Monday. Although the Moon starts slipping into Earth’s dark shadow at 11:27 pm, look for subtle gray shading on the lunar surface beginning 30 minutes sooner. This is the penumbra, a lesser shadow created when Earth partly covers the Sun as seen from the Moon. Between 11:27 and 12:29 am the dark umbra will creep across the lunar surface toward totality. Note that the umbra appears on the left side, which indicates the Moon is moving eastward in its orbit rather than the westward motion we see as our planet rotates. Also, note the curvature of the shadow. The Greeks noticed the curvature more than two millennia ago and correctly assumed it was because the Earth is spherical. Watch for more stars to appear as totality approaches and the sky darkens.
Totality lasts for about 85 minutes, ending at 1:54 am. The Moon could take on a red or orange hue before and during totality, caused by our atmosphere acting like a prism and bending the red part of the sunlight moonward. It could also appear darker than usual if volcanic dust from the Hunga Tonga eruption in January remains high in the atmosphere. You might also note that the bottom of the Moon is brighter than the top. The Moon passes just below the centre of Earth’s shadow during this eclipse, so the lower portion is farther from the deepest and darkest part of the umbra. For an hour after totality you get to watch the partial phase play out in reverse, followed by the fading of the penumbra.
Our next lunar eclipse will occur on the morning of November 8, with the Moon setting shortly after the end of totality. After that we will have to wait until March 14, 2025 to see the shady Moon.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 5:47 am and sunset will occur at 8:43 pm, giving 14 hours, 56 minutes of daylight (5:55 am and 8:46 pm in Saint John). Next Saturday the Sun will rise at 5:40 am and set at 8:51 pm, giving 15 hours, 11 minutes of daylight (5:48 am and 8:54 pm in Saint John).
The Moon is full and near the middle of Earth’s shadow very early on Monday. Mercury is moving sunward rapidly on its way to inferior conjunction next Saturday. Mars passes a moon-width below Neptune on Wednesday morning but the low altitude or twilight will make this a difficult sighting in a telescope. As Mars closes the gap to Jupiter, Venus races eastward against the stars to widen the spread of the four morning planets. Early rising Saturn is starting to look lonely far to their west.
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.
Questions? Contact Curt Nason.