Capturing Iridium flares can be fun to do and it can be very easy to do, from anywhere..
What do you need:
Any camera will work where you can have an exposure setting of about 30 seconds.
Many of todays Digital Point n Shoot cameras can do this and Digital SLR cameras can as well.
You will need a tripod of some sort to hold the camera steady during the exposure.
If you have a remote shutter release cable this will be great. If not you can use the camera's built in 2 second self timer to avoid camera shake while you click the shutter button.
Manual Focus- The Ability of your camera to let you manually focus to infinity is the main key factor. Many Digital Point n Shoot cameras do not have this ability. if yours does not, I'm not sure how well this will work out for you.
Setup: Once you get the time and date of the flare you want to capture, allow your self 10 minutes prior to this time to set up your camera and make sure the settings are correct. I usually fire off a few test shots to make sure the focus, ISO, shutter speed and aperture are all set to where I want them as you only get 1 shot at this a night usually.
When to start the exposure: If you have a GPS time source or a very accurate watch start the exposure maybe 2 seconds before the time of the flare. Or simply watch for the satellite and once you notice it getting slightly brighter start the exposure and end it when ever you want (after it ahs gotten fully bright of course).
What is an Iridium Flare? It is a small telecommunications satellite in low orbit around the earth. The "Flare" is the result of the sun light reflecting off of the satellites solar panels. You will see the satellite traveling across the night sky just like an ordinary satellite does, but if the conditions are right for where you are standing, you will see it get MUCH brighter for roughly 10 to 20 seconds.
Finding an Iridium Satellite - Someone wrote a very precise program to predict when an Iridium flare will occur based on your physical location. You must be a registered member of the
http://www.heavens-above.com/ web site (registration is free and they do not send you junk mail) to get this information.
I have been a member of this site for about 6 years now.
Once you enter in your location (come on use all that GPS gear you have to get precise locations) where you will be viewing at you can view the satellites for the next 24 hours or the next 7 days. So if you are planning a trip somewhere and have the lat and long info, set up that location and see if you will get to see one. Sometimes you wont have any for a few weeks, then you have some just about every day. for a week or so. You can set up multiple viewing locations in your profile so you can easily check your favorite places just before heading out.
Understanding the data on the heavens-above web site can be tricky so I have explained some of the data fields below. You can also click on many objects (in blue) on this web site to get more data than what I can go into here
Date: the day the flare will pass over
Local Time: This time is very accurate (-/+ 1 second) and is the time where you will be standing.
Intensity (MAG) this is how bright it gets ( the smaller the number, the brighter it is, more info below)
Atl.: Altitude above the horizon. 10 degrees is roughly the same size as your fist at arms length away from your eyes
Azimuth: direction in which the Satellite will come from (compass directions in degrees)
Distance to Flare Center: this is the MOST critical data. this is the distance from you to where halfway point of the flare will occur (flare center). if the distance is greater than 12 km away it will not appear very bright. if you get one that is between 1 and 10 km away it will be very bright. anything over 20 km away you may not eve notice the change in brightness.
Intensity at Flare Center (MAG): this is how bright it will PEAK at around half way thought its brightening.
Satellite: this is a name of the satellite passing over.
here is the location data I use for the Chisos Basin: Big Bend (Chisos), 29.328°N, 103.313°WIridium help pagehttp://www.heavens-above.com/iridiumhelp.asp?lat=0&lng=0&alt=0&loc=Unspecified&TZ=CETIntensity (MAG): this is the intensity magnitude or how bright an object in the night sky is. Ancient Astronomers started to catalog stars and other objects in the night sky by brightness. a star with a MAG 1 was very bright, a star with a MAG 10 was very dim. Some objects were later discovered to be much brighter than a MAG 1 and instead of changing thousands of stars "rating" they went with negative numbers. The Sun has a brightness of -27 the moon is a -12, Venus is a -4.7 and very faint stars are +24, +30. The Star Sirius is the brightest night time star at a -1.5.
The unaided night adapted human eye can see down to Mag +6.
this is my web site page for Iridium Flares.
http://www.nightshooter.com/gallery/Astro/WideField/flares/index.htmlNow go have some fun......
James
edit: forgot to mention that the flares occur just after sunset and just before sunrise, some even happen an housr or so before sun rise or sunset.
