Wednesday, September 19, 2007

jupiter's triangle!

tonight in the southern skies, you will notice a very bright jupiter, forming a triangle with the star, antares below it and the filling crescent moon to the left!

also, straight overhead you'll notice a bright star... vega! this is one star of the bright summer triangle.



Jokermage said...

Jupiter has been in the vicinity of Antares for while, hasn't it? I remember seeing them together back in June. How fast does Jupiter move across the sky?

Unknown said...

good question!

you're right, jupiter has been near antares this time around. the planets move across our sky more quickly than the background stars, but the farther away the planet from us, the slower it moves.

hard to quantify exactly how fast jupiter moves across our sky. it has a twelve year period so in one earth year, jupiter moves 1/12 of the way around it's orbit. so it will be visible in our sky for about 5 months or so before it moves behind the sun. it's starting to move low in the evening sky again from here in north america and i remember seeing it in june too... so thats about 5 months.