Tonight at 8:41, something interesting is going to happen in the night sky.

If the weather’s good, you might want to step outside a few minutes early, find a comfortable spot away from the light, and let your eyes adjust.

Look to the north northwest. The object is going to appear about ten degrees above the horizon, which is the equivalent of the width of your fist, held at arm’s length.

Starting at 8:41, and for the three minutes that follow, assuming conditions are favorable and you’re not tucked away in a valley, you’ll see what looks like an airplane on a low approach. But if you look closely, you won’t see a strobe; and you may wonder what has become of the familiar red and green navigation lights.

This strange, steady light will move across the sky from west to east, disappearing at 8:44 in the northeast. It won’t get visibly smaller. It’ll just wink out, almost like a shooting star.

If you miss the 8:41 showing, don’t worry. There’ll be another quickie at 10:18. It’ll be higher in the sky this time, at about two-and-a-half fists, and will come and go in the north northwest, remaining visible for less than a minute.

Truth is, even if the weather is lousy tonight, you’ll have plenty of opportunities to see the International Space Station (ISS) in the weeks and months to come.

We saw it by accident last week, sitting out in the tub, stargazing. I thought it might be the ISS, but I’ve been fooled before. Shana will never let me live down the time we held a backyard vigil, hoping to see the Space Shuttle in a low orbit preparing to land. I was standing watch on the deck, and when I saw a bright light in the western sky, I called her out from the kitchen and announced, in a voice thick with drama, “There it is.”

Of course, it took about ten seconds for us to realize that my so-called Space Shuttle was actually a passenger jet on approach to Harrisburg International.

So this time I played it a little cooler and suppressed the crowing until I’d visited NASA’a excellent “Spot the Station” website (http://spotthestation.nasa.gov), which confirmed that we’d seen the ISS, and provided me with the information about the passes it’s going to make over Perry County this very evening.

The ISS is more than 200 miles away from your naked eye. The fact that it can so easily be mistaken for an ordinary airplane should give you a sense of its enormous size. And if you happened to see the movie Gravity, which won its director, Alfonso Cuaron, this year’s Oscar for Best Director, you’ll remember what a sprawling installation it is, a gargantuan Erector set of shiny capsules, bright girders, and outspread solar panels.

At a crucial moment in the movie, a cloud of space junk rips through the ISS, shredding it like Mexican cheese. This is bad news for the astronaut played by Sandra Bullock, who has maneuvered to the ISS in the hope of using it like a life raft. The destruction happens during a spacewalk, when she’s particularly vulnerable to the millions of deadly new shards spawned by the ISS’s spectacular demise. The special effects are sensational; the scene looks hyper-realistic.

But it should surprise no one that the scene is based in fantasy. The rescue proposed by the movie, which involves Ms. Bullock jet-packing from the Hubble Space Telescope, which she had been attempting to repair, over to the ISS, is basically impossible. The ISS is in a low earth orbit that takes it over the northern hemisphere – one of the reasons it’s so easy to spot in Pennsylvania — whereas Hubble’s orbit is about 100 miles higher, and equatorial.

The ISS can use whatever good press it can get these days, even if it comes in the form of a Hollywood disaster film. To date, it has cost more than 150 billion dollars, making it perhaps the most expensive structure ever built, and hasn’t produced the kind of breakthrough science promised by its original promoters.

What it has produced, in its 14 years of continuous occupation, the longest span of any spacecraft, are reams of data on the long-term health implications of human space exploration.

In these times of international austerity, the appetite for a budget-busting, mind-bogglingly complex United Nations in space has waned; nevertheless, a few months ago the White House announced that the life of the ISS would be extended to 2024.

This is good news for anyone who thinks that mankind’s destiny lies in the stars; and just another example of wasteful government spending for anyone who doesn’t.

The debate rages on. Meanwhile, the ISS glides along in silent splendor, free for the viewing, like clockwork, in the heavens near you.