13 July 2007

Venus - 13 July 2007

Date: 13 July 2007 U.T.
Time: 2:50 U.T.
Telescope: 80mm f/5 achromat
Magnification: 85x
Filter: #56 Light-Green
Seeing: Fair
NELM: Bright Twilight
Temperature: +80 F (+27 C)


The above (mirror-reversed) sketch has North up and Preceding to the left. It shows the basic appearance of Venus as seen in a small telescope.

As the planet's phase changes from full to quarter (half) to crescent to new the planet's disk appears larger and larger. When Venus's phase is near full the planet is on the far side of the Sun. When the planet is a crescent it's on the near side of the Sun. These changes have a dramatic effect on the apparent size of the planet as seen in a telescope.

Currently Venus is moving closer to Earth as it orbits the Sun. As a result it's appearing increasingly larger as seen in a telescope and its phase is becoming a thinner crescent.

Venus is currently visible in the evening sky in the west immediately following sunset. It's by far the brightest object in that area of sky and readily visible to the unaided eye.

No comments: