— For a loose-knit group of amateur sky watchers skilled at tracking satellites – sometimes with little more than a stopwatch and a pair of binoculars – the last couple years have been anything but uneventful.

In late January, Eutelsat‘s W2M telecommunications satellite shutdown without warning just five weeks after reaching orbit. Last fall, a U.S. Air Force missile warning satellite known as Defense Support Program-23 crapped out and now poses a potential threat to nearby satellites. Several months earlier, the U.S. military shot down one of its own classified satellites with a ship-based Aegis missile. The downing of USA-193 took place roughly a year after
‘s provocative 2007 shootdown of a defunct weather satellite.

Such events, while little noticed by the general public, are marquee events for dedicated do-it-yourself observers like Greg Roberts, a
Cape Town
South Africa
, resident who has been tracking satellites since 1957.

Roberts, a pioneer in the use of telescopic video cameras to track distant satellites, said satellite spotters run the gamut from the casual observer interested in catching the occasional glimpse of the international space station as it passes overhead to the hardcore satellite sleuth adept at finding objects not listed by the U.S. Air Force Space Surveillance Network through its Space-Track database.

Roberts is part of a small but dedicated group of satellite spotters who share their observations via a no-frills Web site called the SeeSat-L home page.

Since it was launched in 1994, SeeSat-L has become an important tool for satellite observers who use it to post their sightings. The group’s hardcore backbone of seasoned, dedicated observers numbers perhaps 20.

“With so few members we are pretty thin as the world is pretty big … but we are slowly expanding and the group is constantly looking for new talent that could expand the network,” Roberts said. “Unfortunately the talents required are fairly rare and what has been achieved is quite remarkable. Maybe one day we will have a unified space force that has an active worldwide capability … but that day is not yet in sight.”

While some skilled satellite observers such as Roberts use highly sensitive video cameras mounted to telescopes and capture reams of data with DVD recorders and computer hard drives, some of the most important contributions come from those who continue to use nothing more than binoculars, a stop watch and a good star atlas.

John Locker of
, praised these minimalists as “the real observers who diligently watch the sky and note when satellites pass by or near to visible stars and planets.”

Such records “can provide important information allowing the mathematicians in the group to calculate and check orbital data,” Locker said. “Very often unlisted – often classified – satellites can be acquired in this way.”

Another leader of the satellite watching community, Ted Molczan of Toronto, highlighted his contributions to discoveries relating to the U.S. Misty 1 and 2 stealth satellites as an example of what amateurs can accomplish – and the satisfaction it brings.

“Satellites in secret orbits provide the finest test of my observational and analytical skills, and an opportunity to contribute to public knowledge,” he said.

said amateur satellite observers perform a public service by tracking objects that as far as the U.S. Air Force’s unclassified Space-Track listings are concerned do not exist.

“[I]n a recent year, our group of about 20 observers collectively made nearly 21,000 observations of more than 1,400 objects,” Molczan said. “This includes approximately 18,000 observations of about 200 objects in secret orbits, for which we are the only regular public source of orbital data.”

Roberts said not all unlisted objects are classified satellites.

“In many cases these objects are not really classified,” Roberts said. “Simply, in some cases Space-Track has lost the object, which might be nothing more than a large piece of debris.”

Amateur sky watchers, however, are not shy about finding and tracking satellites the world’s governments do not admit exist.

“The U.S. government needs to accept [the fact] that many of the satellites it relies on for national security purposes can be easily seen and tracked by amateurs with very modest equipment,” said T.S. Kelso of The Center for Space Standards & Innovation in Colorado Springs, Colo. He operates CelesTrak that posts info on the orbits of satellites and spacecraft debris.

“Assuming that U.S. adversaries can’t do the same ignores fundamental realities and actually puts U.S. national security at risk, particularly when information on the location of these satellites is withheld from other satellite operators who are trying to avoid close approaches,” Kelso said.