2009 April 20


My folks used to live in the Santa Cruz mountains -- where it's nice and dark. They had a hot tub outside. When I'd visit, a dip in the tub at night was usually a nice thing. A couple of times, I'd luck out and spot a satellite zooming overhead. It was always a neat experience imagining this thing out there that people made -- doing its job, or just caught in orbit around the planet.

img_jpg_eps_instruments_mediumA couple weeks back, I came across a site that publishes the time and path of visible satellites called Heavens Above. You tell it where you are, and it tells you what you can see. Simple! Here is a page that lists very bright objects visible from San Jose, CA. If you alter the minimum brightness value (a higher magnitude number), then more items will be listed. All kinds of satellites are up there. From communications satellites, to weather tracking devices, to the bodies of rockets used to place satellites in orbit. During the last Space Shuttle mission, I was able to see it pass overhead while docked to the ISS. Of course, it was just a pinpoint of light, but it was very cool to know that the little dot of light was housing a group of people.

The couple of hours after sunset and before sunrise are the best times to see satellites, since the satellite will still be illuminated by the sun -- most are 500-1500km above the Earth. NASA has a tool called J-Track 3D that helps you visualize just how much is up there, and how far away it is.

So if you're looking for something to do on these warm summer nights, what could be better than gazing at stars watching for some of man's greatest work to silently slide by overhead.

At the moment, these are the satellites I've seen over the last week: