Tonight and early Wednesday are your last chances to search the night sky for NASA’s space shuttle Discovery before its planned landing tomorrow.

Depending on where you are, and of course weather conditions, you can spot Discovery and the International Space Station fly across the night sky, but you better search fast. Discovery is set to land Wednesday at 1:02 p.m. EST (1802 GMT). (Click here for live mission coverage.)

Here’s a handy primer on hunting for Discovery and the ISS by SPACE.com Skywatching Columnist Joe Rao, who recommends you visit NASA’s Sightings Page, among others, for specific times and dates to aid in your spacecraft hunt.

In general, it looks like Discovery is leading the ISS by either a few seconds or minutes depending on where you are, though most viewing opportunities - they’re listed as Local Time at your location - seem to be occurring just before dawn locally. NASA provides the approach path and maximum elevation in terms of degrees. For example, straight up above your head is 90 degrees, while 0 degrees is on the horizon in any direction.

Bad luck for us SPACE.com reporters here at our New York office. The best we can hope for is a pass that rises about 55 degrees over the horizon coming out of the south-southwest, a bit difficult to spot if you have to peek through skyscrapers and a light-polluted sky.

NASA’s Johnson Space Center in Houston, Texas and Kennedy Space Center in Cape Canaveral, Fla. - where staff writer Dave Mosher is covering Discovery’s return - seem worse off, with viewing opportunities hitting their maximum elevations between 15 and 12 degrees above the horizon respectively.

My folks and friends in Stockton, California, meanwhile, have the opportunity for a primo seat for an ISS overflight at about 5:07 a.m. PST (1307 GMT) tomorrow, when it hits and 83-degree elevation (nearly directly overhead) for a brief three minutes.

If you live in America’s Heartland, you might even get a chance to see Discovery pass overhead as it reenters the Earth’s atmosphere. For the first time since NASA’s 2003 Columbia accident, a shuttle is flying back to Earth over the continental United States.

Bryan Lunney, Discovery’s reentry flight director, encouraged folks to check whether the shuttle will pass over their home states by viewing NASA’s ground track maps available here.

“I would say it’s worth looking for, at least in the middle and near the end,” Lunney said today. “So I would say go give it a shot.”

While covering Discovery’s STS-120 mission, I and several fellow reporters were treated to a beautiful pass over the JSC parking lot. As NASA counted down to launch its Dawn asteroid probe, the ISS and its Expedition 15 crew passed silently over my home in Jersey City last September.

Hunting for manned spacecraft in the night sky is both fun and frightening when you remember that, no matter how beautiful that bright moving light might seem, it houses living, breathing people protected by only inches of glass and aluminum from quite possibly the harshest environment humans have explored.

This entry was posted on Tuesday, November 6th, 2007 at 4:35 pm and is filed under Space & Astronomy. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.