New Delhi, Aug. 7 -- a detail that will matter enormously when the eclipse arrives.

The Waning Crescent on August 7 places the moon 23.88 days into its 29.5-day cycle, with illumination at 34 percent and falling by roughly seven percentage points per day. At a distance of approximately 364,000 kilometers and approaching perigee on August 10, tonight's crescent is not the smallest disk August will show, but it is narrowing visibly each morning. The moon is currently passing through Gemini.

When and where to look

The Waning Crescent is a morning moon. On August 7, it is not visible in the evening sky - the moon sets in the afternoon and does not return until the hours before dawn. Observers should look toward the east approximately 90 to...