Iridium Flares

Discussion in 'Science and Technology' started by Ernie S., May 25, 2012.

  1. Ernie S.
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    Ernie S. Platinum Member

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    I have an app for my Android that lets me know when to look and the direction one will appear. There will be a very bright one to my west in a few minutes

    From Wiki

    Iridium satellite flare
    An Iridium satellite

    The Iridium communication satellites have a peculiar shape with three polished door-sized antennas, 120° apart and at 40° angles with the main bus. The forward antenna faces the direction the satellite is traveling. Occasionally, an antenna reflects sunlight directly down at Earth, creating a predictable and quickly moving illuminated spot on the surface below of about 10 km diameter. To an observer this looks like a bright flash, or flare in the sky, with a duration of a few seconds.

    Ranging up to -8 magnitude (rarely to a brilliant -9.5), some of the flares are so bright that they can be seen in the daytime; but they are most impressive at night. This flashing has caused some annoyance to astronomers, as the flares occasionally disturb observations and can damage sensitive equipment.

    When not flaring, the satellites are often visible crossing the night sky at a typical magnitude of 6, similar to a dim star.
     
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  2. Ernie S.
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    Ernie S. Platinum Member

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    Awesome! As predicted, right on time and a -6 magnitude, much brighter than Venus ever gets.
     
  3. Ernie S.
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    Ernie S. Platinum Member

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    Another flare here in about 25 minutes. This one will be magnitude -2 or a bit dimmer than venus.
    They only last a few seconds and get as bright as magnitude -8 nearing the brightness of the first quarter moon.
     
  4. Peach
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    Peach Gold Member

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    What instruments are required to view? Binoculars or a telescope?
     
  5. asterism
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    asterism Congress != Progress

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    Eyes.

    It's quite cool.

    You can also check this website:

    Heavens-Above Home Page
     
  6. Missourian
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    Missourian Gold Member

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    I have that app too...nothing here until the am. :(
     
  7. Peach
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    Peach Gold Member

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    thanks, Venus transit in progress, visible here Wednesday night.
     
  8. Ernie S.
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    Ernie S. Platinum Member

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    Naked eye, Peach. A telescope or binoculars would limit your field of view and if you did happen to catch one in a relatively large telescope, it might even be painful, like looking ionto the sun.
    They are extremely bright, but last only a few seconds. The smart phone app will tell you the compass heading and the azimuth (degrees from the horizon. Most are nearly due East or West of your location and 40 to 75 degrees above the horizon.
    My app will alert me roughly 1/2 in advance and I set the kitchen timer to give me a few minutes to get outside and let my eyes get used to the light, then as the flare starts to brighten, the phone vibrates.
    The brighter ones, of magnitude -5 or brighter are rather spectacular and if you ever get to see a magnitude -8, you'll swear a motorcycle is bearing down on you. We're talking bright enough to cast a shadow or to be seen in full daylight.
    I just find it cool that they can predict with such certainty the when, where and brightness.
    If you have relatively dark skies where you live, you may even catch the satellite before and after it flares. It would look like a very dim star that is moving across the sky similar to a high flying aircraft. If you are looking in the right place, you will see it get, like 1000 times brighter in a few seconds and them dim just as quickly.
     
  9. Ernie S.
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    Ernie S. Platinum Member

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    I'm getting most of mine between 8:30 and 10 PM I would love to catch one in the daylight! I have seen Venus at noon, but with Venus, you have a lot of time.
     
  10. syrenn
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    syrenn BANNED

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    Very cool!

    what is the name of the app?
     

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