August 20, 2008 - ES Tonight

sagar: Author=’Bruce McClure’ program=” video=”Our sky chart shows the western sky for about 30 to 45 minutes after sunset at mid-northern latitudes. We show the planets Mercury, Mars and Venus, but Venus is the only planet you’re likely to see easily – or at all – with the unaided eye. An unobstructed view westward is needed to catch Venus, blazing close to the horizon.

At 40 degrees North latitude – the latitude of Philadelphia – Venus sets a bit more than 50 minutes after sunset. Farther north, Venus sets sooner after sundown, and farther south, Venus sets later. For the setting times of the sun and Venus in your sky, check our “almanac page”:http://earthsky.org/article/sunrisesunset-moonrisemoonset-almanacs.

Venus is the brightest celestial object after the sun and the moon. Good thing! Otherwise, it’d be much harder to see this world in the twilight glare. For all of August and September 2008, Venus will linger low in the evening twilight and will set before dark. Yes, it’s true that, in order to see this world, you have to catch it at dusk. Starting at mid-October, Venus will stay out longer after dark, but even then the low angle of the autumn ecliptic – or path of the sun, moon and planets – will keep Venus low in the sky.

With binoculars, look for Mercury below Venus. Mercury is as brilliant as a bright star, but it’s hard to see with the unaided eye because of the twilight glare.

Written by Bruce McClure

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