Monday, September 24, 2007

Harvest Moon

This is the time of Harvest Moon. Lots of people use the expression, but not many really know what it means. During the few days before and after the full moon that is nearest the autumnal equinox, moonrise occurs just a few minutes later each night. Since the near full moon rises shortly before or after sunset, farmers can use the light from the it to help them see while they are harvesting the crops in the fields. They essentially receive an extra hour or two of worktime which can really help them during this critical time.

The moon's position on the ecliptic is the reason behind all this. Normally, the moon rises 50 minutes later each night. However, due to the slope of the ecliptic in the sky in late September around 7 pm, the near full moon rises only 15 -20 minutes later, meaning that it is about the same height in the sky at the same time of day in late September. Farther north in Canada, the effect is more dramatic with the near full moon rising 5 minutes later for these next few nights.

For the record, the full moon is at 3:46 pm on Wednesday and the fall equinox was yesterday.

Such is the view from Earth....

Thursday, September 13, 2007

Catch the PBS show "Seeing in the Dark"

The universe of amateur astronomy is a fascinating place populated with interesting people. Find out for yourself by watching the PBS adaptation of the popular book, "Seeing in the Dark," by Timothy Ferris. This show promises to bring the wonder of skywatching directly to you. It is currently scheduled to air on Tuesday evening. Visit:

Crescent moon with Earthshine

On the evenings of September 13, 14, and 15, the crescent moon appears in the southwestern sky just after sunset. It is filled with Earthshine, the sunlight back reflected off the Earth. To its upper left, glows Jupiter. To the moon's lower right, sets elusive Mercury. Jupiter is no challenge to locate, Mercury is.

Such is our view from Earth...

Sunday, September 2, 2007

4 Vesta passes Jupiter

Now that summer's haze has dissipated, much more can be found, especially with binoculars. Last week it was out of sight, but clearing skies provide an opportunity to see the asteroid Vesta. It can be found over the next several evenings just to the upper left of Jupiter. Use a pair of household binoculars (10 x 50) to see this. It will be a dim "star." Compare Vesta's 178 million mile distance with the much brighter Jupiter at 484 million miles away. Good Hunting!