The beginning of astronomical summer in the Northern Hemisphere coincides
with Mars, Venus, and the crescent moon's "Earth-shining" closest alignments
through 2028.
The summer solstice, which occurs on June 21, may be a significant annual
event on Earth, but except the fact that the sun is at its zenith in the
Northern Hemisphere, it is not traditionally a time for stargazing. That
changes in 2023 when Venus, Mars, and a thin crescent moon emerge in the
western sky during the solstice's evening twilight.
According to When The Curves Line Up, viewers in North and South America
won't see the three heavenly bodies so closely together again until March
28, 2028. It's a beautiful week to be outside in the twilight, and Da Vinci
glow (also known as Earthshine, or sunlight reflected by the Earth onto the
dark lunar surface) is visible on the waxing crescent moon. Alignments also
emerge on the evenings before and following the solstice.
On Monday, June 19, at twilight low on the western horizon, use stargazing
binoculars to locate the smallest crescent moon imaginable. Given the
brilliant sky after sunset and its illumination level of slightly over 3%,
it could be challenging to see.
A somewhat brighter and higher crescent moon will create a line in the sky
with bright Venus and faint Mars the next evening, Tuesday, June 20. The
moon will have an illumination level of about 8% and exhibit a striking Da
Vinci glow on its shadowed limb.
According to Timeanddate.com, the three bodies will be most visible on
Wednesday, June 21 during the first twilight after the summer solstice. A
right-angle triangle formed by Mars, Venus, and a 13% lit crescent moon will
signal the beginning of astronomical summer in the Northern Hemisphere,
however dull Mars may be difficult to see without binoculars or a fine small
telescope. Watch out once more for the Da Vinci light on the moon.
The next evening, on June 22, a 21% lit crescent moon will once again align
with Mars and Venus, but this time from above the duo. This will be the last
glimpse of the week. Additionally, the moon will be close to Regulus in the
Leo constellation.
All of these sights are visible with the unaided eye, but a set of
stargazing binoculars or a telescope will be useful for a breathtaking
up-close view of the Da Vinci glow on the lunar surface.
