Skywatch Line for Wednesday and Thursday, August 30 and 31, 2023

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday,
August 30 and 31, written by Alan French.

The Sun rises at 6:18 A.M. on Wednesday and sets at 7:33 P.M. On
Thursday it rises at 6:19 and sets at 7:32. This Thursday has just over
19 minutes less daylight than last Thursday.

The Moon will be full Wednesday night. It reaches full at 21:37, just 9
hours and 43 minutes after it reached perigee, its closest point to
Earth. Its closeness to Earth will makes Wednesday’s Full Moon the
closest and largest of 2023, now commonly called a supermoon. How much
larger does the full Moon appear when the Moon is near perigee than when
it is at apogee, its farthest point from Earth?

At perigee the Moon is 306,000km (224,000 miles) from Earth. At apogee
the Moon is 405,000km (251,655 miles) from Earth. The Moon appears 17%
larger at perigee than it does at apogee. This translates to the perigee
full Moon appearing 30% brighter than the apogee full Moon. It is, of
course, not a comparison we can do directly. Supermoons and micromoons
are separated by months and can only be compared in our memory. There
are, however, photographic comparisons of their size available on the
web. Simply do a search of “micromoon versus supermoon” and click on
“images” in the results.

Wednesday’s supermoon rises at 7:48 P.M. as seen from Schenectady. Its
azimuth will be 108 degrees, roughly east southeast, when it rises. To
watch the rise of Wednesday’s supermoon, you’ll want a location with a
good view to the east to southeast. By 10:00 P.M. the full Moon will be
20 degrees above the southeastern horizon. Look for Saturn just over 5
degrees to the upper right of the Moon.

On Thursday night the Moon will rise at 8:13 P.M. toward the east. When
it rises it will be 98 ½ percent in sunlight and will still look quite
full by eye. Its eastward motion against the stars will have moved it so
it lies 19 ½ degrees from Saturn, now well to its upper right.

Any modest telescope magnifying 50 to 60 times will show Saturn’s rings.