Update: After teetering on the edge of oblivion, the Iridium communication satellite constellation
is back in business. An investment group purchased the constellation and its ground support
network for a song (relatively speaking), and will be marketing it to targetted niche
customers. Not surprisingly, the US armed forces will be the anchor customer, using the
system for nonsecure backup communications.
One
of the more interesting lights in the sky come from a series of communication
satellites called Iridium.
These satellites have an antenna that is similar to a dressing mirror in
size, shape, and reflectivity. So what? Well, from 485 miles
up, if that mirror is aligned just right, it will reflect the sun towards
you, becoming the brightest thing in the sky. In astronomical parlance,
these Iridium Flares can be as bright as magnitude -7 (brighter
than Venus ever gets). They last for only a few seconds at a time.
So, how do you know when and where an Iridium Flare will happen?
Well, there's an excellent web site called Heavens-Above
that will happily calculate the Iridium flare
schedule for any place on Earth. You can go
to their site (which can also show you when Mir and many other
satellites will be overhead), or you can check out the schedules for San
Diego or Los
Angeles. Note that the more precise you are about your location,
the more accurate the flare prediction will be.
You can determine
your latitude and longitude quite precisely using mapping software
such as Delorme's Street Atlas,
a really cool, free tool called Google Earth,
or web map servers such as
Geocode.com.
Here's how to do it using Geocode.com:
Enter your address and press the "request" button;
Press the "Show the results" button;
A table lists your latitude and longitude. Record the "decimal" values;
One
of the more interesting lights in the sky come from a series of communication
satellites called Iridium.
These satellites have an antenna that is similar to a dressing mirror in
size, shape, and reflectivity. So what? Well, from 485 miles
up, if that mirror is aligned just right, it will reflect the sun towards
you, becoming the brightest thing in the sky. In astronomical parlance,
these Iridium Flares can be as bright as magnitude -7 (brighter
than Venus ever gets). They last for only a few seconds at a time.