The stunning crater Posidonius is placed perfectly for viewing on the lunar disk tonight, now well illuminated by the Sun. | Published: April 24, 2026 Looking for a sky event this week? Check out our full  Sky This Week  column.  April 23: A conjunction of Venus and Uranus By evening, the waxing Moon is in eastern Cancer, not far from the Beehive open cluster (M44). This lovely grouping of stars shines at third magnitude and covers roughly a degree on the sky — it’s a great binocular target, even with the Moon nearby.  If you’ve got a telescope available this evening, turn it toward the Moon to scan around the sunlit portion of the disk as the terminator dividing night and day continues sweeping westward. The Sea of Serenity looms, dark and circular, just northeast of the terminator in the Moon’s northern hemisphere. Look along the northeastern rim of this mare to find the well-defined crater Posidonius.…