Get ready folks. Itís about to begin. First it
will be a UFO report:
"I was looking at the sky when I noticed
this light traveling along that got brighter and brighter. I knew
it wasnít an airplane because there were no red lights. Just a
bright light that got incredibly brighter. It nearly blinded me.
It couldn't have been from this world."
We will explain to them that what they saw was
an Iridium satellite. Then the government conspiracy theories will
"Have you seen those bright
flashes in the night sky? The government is radiating us with iridium.
Itís part of a vast conspiracy to sterilize males and control population
We will tell them that is hogwash. They will respond
by quoting a quatrain from Nostradamus in which he predicted these
events. When they discover that there are to be 66 of these satellites,
they will make the minor jump from 66 to 666 and tell us how the
Antichrist is behind it all.
Mark my words.
Whatís Going On?
The scariest animation of the year (74K) shows the armada of
Iridium satellites in low earth orbit. Click on image to view.
Animation from Iridium company site.
While we wait for these events, letís enjoy this
brief window of sanity and enjoy, or vilify (depending on your viewpoint)
this phenomenon. In the May 1998 issue of Sky & Telescope Philip
Chien wrote an excellent primer on Iridium flares. There are also
a number of web sites covering the subject. Links are provided at
the end of this article.
Beginning May 1997 Motorola began launching a
series of communications satellites known by the commercial name
Iridium. The satellites have no association with the element iridium
beyond the name. Each satellite has three antennae. Each antenna
is about the size of a typical door in your home and is is a near
perfect mirror. When they are oriented just right a small portion
of the earth will receive an nearly perfect reflection of the Sun.
A perfect "hit" will produce a flash of Ė8 magnitude.
If the Sun were a door sized object it would shine at a bit more
than Ė8 magnitude. This is bright enough to cause dim
shadows on the ground. There are reports that Iridium flares have
been visible as glows in thin cloud-covered skies. However the magnitude
drop off is rapid. A person at the center of the flash can see a
Ė8 magnitude event while someone twenty miles away will only see
a Ė4 magnitude (equal to Venus in brightness) event. Just using
the phrase "only as bright as Venus" to describe a diminished
apparition tells you that we are dealing with a new thing in the
Show Me The Money
Ed. Note: A new RTMC flare photo from John
Sanford is here.
The exciting thing is that these flares can be
predicted with amazing accuracy. At the 1998 Riverside Telescope
Makerís Conference several predicted flares were observed by hundreds
of observers. One, a Ė7 magnitude event, drew such a huge cheer
from the crowd that it could be heard a mile away. Stephen Edberg,
an RTMC leader, commented that "hearing" the flares (i.e.
the crowd) was nearly as exciting as seeing them. Another flare
on the same night only reached Ė4 magnitude but was accented by
a bright meteor during itís passage.
of a -4 magnitude flash from an Iridium satellite and a bright meteor
passing through Cygnus as observed at RTMC on May 24, 1998. Animation
copyright by Russell Sipe. Background stars from The Sky Level IV
by Software Bisque.
The Good, or the Bad and Ugly
On any given night an observer could see a half
dozen or more of these flares. Most will be dimmer than the 8
monsters. You can expect to see a 6 magnitude or greater flare
once or twice a week if you know where to look.
The flares can be a disruptive element to amateur
astronomers conducting wide field astrophotography. The most dedicated
photographers will run programs that predict the passage of these
objects so as to avoid them. Obviously, most amateur astronomers
look upon these satellites as just one more step along the slippery
road of increased light pollution.
On the other hand, we have an opportunity here
to make lemonade out of lemons. The Star Wars generation has been
hard to impress with telescopic views of deep sky objects, and our
explanations of the vastness of the universe. They are attune to
exploding death stars and celestial dogfights. Their WOW factor
is set very high. Getting them to come to a dark sky site to get
wowed at the eyepiece is very difficult.
Fortunately astronomers have had a couple big
wowsers in the last few years that have attracted the interest of
the public. First it was Shoemaker-Levy-9ís title bout with Jupiter.
Then it was the Comet Hale-Bopp media tour. And the Hubble Space
Telescope chimes in every six months or so with some incredible
photo that makes the network rounds. So the one time big events
have been there.
Now, with Iridium flashes, there is an ongoing
predictable wowser than can serve as a trojan horse to lure unsuspecting
light pollution dwellers into the dark and majestic world of astronomy.
The Iridium satellites could become astronomers unwitting partners
in building an interest in the night sky if they will seize the
day, or should I say seize the night.
Become an expert in these objects. Learn how to
predict their passage. Wow your friends. And tickle the interest
of a potential new amateur astronomer. Or, depending on your personality,
you could also predict the next UFO/government iridium flash over
your boss's house.
Some Links for Iridium Satellite Information
a Flaring/Glinting Iridium
The basic Iridium information can be found here. You will also find
links to the shareware programs used to predict satellite passes.
Iridium Satellite Network
The Iridium system is explained at the Iridium company web site.
Celestrak provides the two-element sets for the Iridium (and many
This is a web-based satellite prediction program.
Uwe Reimann is building a site containing Iridium flash videos.