But thanks to Uncle Sam, there’s no rush (Sky & Telescope August 2001). Our DoD has purchased 40% of the system capacity for military use over the next two years, plus an option for five more. Iridium Satellite LLC, the new legal owners of the system, is marketing to the commercial sector and has signed-up several re-sellers. To ultimately make a profit, the business plan has necessarily changed: their market is no longer for portable phone systems, but for data communications to remote locations on the globe where cellular and microwave won’t work.

So Iridium flares will continue to surprise and delight stargazers. Last month, they served as a perfect target for my new toy, a super low light surveillance video camera, the PC164C from Supercircuits.com. This tiny camera comes without power supply or lens, but a bit of scrounging located a 12-volt adapter and a useable C-mount lens. Right out of the box, I was impressed by its sensitivity: I was able to videotape Comet Ikeya-Zhang setting in the northwestern twilight. Not only was M31 the Andromeda Galaxy faintly visible nearby, but also 4 - 5th magnitude stars shown clearly on the screen.

Flares are really bright, often magnitude 0 or brighter. Along the narrow ground track, -8 magnitude is possible, making Iridium satellites momentarily the 3rd brightest things in the sky. Flares are quite predictable (You can almost set your watch by them!), but predictions must be made for your exact location. Fortunately, these are easy to do on the web at www.heavens-above.com: after selecting your location, you receive a table of dates, times, altitudes and azimuths, and predicted magnitudes. Curiously, the flares seem to come in runs and appear in consistent parts of the sky. Probably this has something to do with the interlocking orbits, but that will have to wait for another time.  Back to the video camera.

At right are time lapse sequences grabbed from a videotape of two flares. The camera was rubber banded to a tripod, aimed in altitude with a level from my garage, and eyeballed in azimuth to the left of Polaris. I pressed the record button just in time and caught a flare. A fluke? Just lucky? A couple of nights later, in the same part of the sky, I caught another flare on tape. Must be skill. Suitably encouraged, now the fun starts. More challenging would be a full pass of the space station. Could this thing record meteors? What about a flickering aurora? Would it be possible to study and measure seeing conditions to compare observing sites? You need to think out of the box: the ability to record changes in brightness and motion open up many possibilities of wide angle astro-imaging in real time.

So like the Iridium satellites themselves, my video camera is equipment in need of a mission. This same camera has caused quite a buzz on the International Occultation Timing Association and videoastro Yahoo group web sites. Its sensitivity is a huge advantage for those recording and timing occultations of stars by the Moon. There is great promise for group observing on a budget or detailed imaging of the lunar surface. What about a video survey of the Moon, a cure for cloudy night observing? Perhaps a tour of the Apollo lunar landing sites? Play "spot the flag"?. The only downside of which I am aware is that this camera has only a limited ability to adjust the automatic gain sensitivity to light, thus I have not found it useful for the bright planets. At least not yet. So stay tuned, something this fun and easy to use has to have a better use than peeking in your neighbors windows... 

Iridium flares first appeared in this column in December 1997, photographed with conventional 35-mm film technology. Like back then, Moondark is written by Doug Miller, published on the web, and printed in the Delmarva Star Gazers' Star Gazer News. Please address comments and suggestions to dcmiller@dmv.com. This document was last revised on 23 May 2002. All text and images copyright © 2002 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.