New Delhi, Aug. 13 -- the darkest skies of the entire lunar month, falling on the final night of the Perseid meteor shower's peak window.

36 p.m. UTC when the August New Moon completed its conjunction with the sun. The lunar disk carries roughly 2 percent illumination tonight, meaning it will set well before 9 p.m. local time across most of the Northern Hemisphere. After moonset, the sky belongs entirely to the Perseids and whatever naked-eye planets are above the horizon. For those who track the moon's astrological position, the crescent spent the earlier part of Thursday void of course in Leo before entering Virgo in the late afternoon.

The timing is close to ideal. Astronomers regard a new or near-new moon as the single most importan...