We finally have liftoff. Congratulations, NASA, sixth time's the charm.

Now we wait for the shuttle to catch up and dock with the International Space Station, which should happen around midday Friday. Here'a site that lets you follow the choreographed dance between the two vehicles in more-or-less real time:
http://spaceflight.nasa.gov/realdata/tracking/

Once the two spacecraft are docked together for their 16-day rendezvous, they should make a spectacular sight from Earth.

For one thing, as of March the ISS now has its complete array of solar panels, so it's more reflective than before. The shuttle hanging off it should make it even brighter. And the coming week will feature at least three direct passes over either Montreal or New York City in prime viewing periods (roughly 9 p.m. to 11 p.m.)

The sky has had time to get dark, but the ISS-shuttle combo is high enough (about 200 miles up) to still be fully sunlit. The visual result is a magnitude of more than -3, which is almost as bright as Venus ever gets. But neither Venus nor the moon will be in the sky those nights, making the ISS the brightest thing in the heavens.

For a very brief period! Typically, it takes maybe four minutes to zip from horizon to horizon. It's moving more than 17,000 mph. And on some passes, it enters Earth's shadow before reaching the eastern horizon, so the viewing opportunity can be over in a minute or two.

For stargazers in the New York area, assuming clear skies, there's a really good pass on Thursday, July 23. Look northwest at 9:43 p.m. The ISS should just be clearing the horizon. Five minutes later, it will be almost directly overhead -- and a minute later, it will instantly vanish as it enters Earth's shadow.

Readers living elsewhere can go to heavens-above.com and punch in their town or city (or longitude and latitude if they know them). Print out a weekly list of ISS passes, and focus on those with a predicted brightness of -2 or (ideally) -3. Those will be the closest to your location and also tend to be visible the longest.

I'll admit I'm particularly interested in this shuttle-ISS mission because it marks the first time two Canadian astronauts have been in space at the same time. But if you live in any of the 16 countries that are partners in the ISS, you should be paying some attention. This project has cost us all, collectively, $100 billion.

Construction of the ISS is only being completed this year, but U.S. funding is due to stop in six years. If that happens, the whole thing will be de-orbited to burn up over the Pacific. That would be kind of a colossal waste.

Here's the view the shuttle astronauts will see Friday as they approach the ISS for docking: