In the last few minutes of a partial eclipse that will become a total eclipse, a lot of things begin to happen. The sky's gradual darkening becomes more sudden, and in the final moments the sky darkens as quickly as if someone were working a huge celestial dimmer switch. From the west, or northwest, or southwest – wherever the shadow is coming from – the sky is blackening even more rapidly. Clouds might still be visible even though there is very little sunlight left to fall on them. The Sun itself appears as a crescent so thin that it appears only as a line.

Venus appears

At almost every eclipse, between ten and seven minutes before totality begins, someone will yell a single word: “Venus!” Everyone then strains to catch a glimpse of Earth's hellish sister planet. Venus is a symbol. The sight of our neighbor world means that the sky has darkened sufficiently for the brightest planet to appear along with the crescent Sun. Along with the appearance of Venus, shadows are becoming very sharp and distinct. Just prior to totality during the eclipse of April 2005, Venus appeared due north of the Sun. The planet was near its conjunction; less than a year earlier it actually transited the Sun for the first time in more than a century.