I spent some time outside and I saw a few things of interest. First was a bright spot in the sky that I saw well before the sun set. I spied it through my telescope and saw it to be a weather balloon. My optical set-up was giving me only 16x magnification, so the photograph I took didn't show much detail, so I enhanced it (with debatable success which you see at left) to show the balloon's components. The radiosonde (weather instrument package) that's hanging from the balloon is the small spot at about the 5 o'clock position. Click for a larger image.

Second was Jupiter. I had heard that starting a few months ago, this great planet's southern equatorial belt had faded to almost invisibility. For my entire life, I've always seen Jupiter with a prominent belt in both its northern and southern hemispheres, but when I turned my telescope to it tonight, I saw that indeed the southern belt was gone. This isn't unheard of. Jupiter has lost a belt several times over the last 100 years. I just hadn't seen it in this state before. It's estimated that the belt will reappear sometime in the next few months. As a bonus, Io, Jupiter's innermost large moon, was just off the western limb of the planet. Two and a half hours later, I saw that it had moved the full planet's diameter away. Planetary dynamics at work!

Next was the International Space Station (ISS). If you ever want to know when this (or any other bright satellite) will be making a pass in your sky, go to http://heavens-above.com. You can save your location by becoming a registered user, or select your city from a world-wide database.

This series of three photographs document the ISS's two minute pass over Tucson. Each photo was shot at 400 ASA, but using an exposure time of 8 seconds. Therefore, the ISS appears as a streak in contrast to the stars as it moved. This pass was a full hour after sunset, so the space station disappeared into the Earth's shadow by the time it was overhead. (A pass occurring closer to sunset can be seen nearly horizon to horizon.) It showed an obvious reddening as it dimmed from sight and the astronauts onboard experienced their sunset.

Here it is a little closer. It has a speed of 17,000 miles per hour, so during the 8 second exposure, it covered a distance of 38 miles. Being a junkie for numbers, I also figured out the station's apparent size in our sky. Being 250 miles up, with the longest dimension being 356 feet, the fraction of a complete arc the station subtends is 55 arc seconds. The equation is 55"=(.06742/(250 x 2 x Pi)) x 1,296,000

The values used are:

.06742=length of space station in miles

250=orbital height in miles

1,296,000=number of arc seconds in a complete circle

For example, this compares with Jupiter's maximum size of 49", so with a suitable tracking telescope, it's possible to see details in the space station's structure.

This last photo illustrates how it fell into darkness behind the Earth. I've labeled the background constellations (with two notable stars in parentheses). My camera was pointing almost straight up here.