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Ring around moon

  • 25-12-2015 12:38am
    #1
    Brussels Sprout
    Registered Users, Registered Users 2 Posts: 7,834 ✭✭✭


    There's a massive ring around the moon tonight. It's like the moon is the centre and then there's a white circle surrounding it. It almost looks like a giant wheel with the moon as the axle. Can anyone explain this phenomenon? I'm in Cork btw


Comments

  • #2
    uck51js9zml2yt
    Closed Accounts Posts: 18,268 ✭✭✭✭uck51js9zml2yt


    Brussels Sprout wrote: »
    There's a massive ring around the moon tonight. It's like the moon is the centre and then there's a white circle surrounding it. It almost looks like a giant wheel with the moon as the axle. Can anyone explain this phenomenon? I'm in Cork btw

    Can't see the ring in Dublin.


  • #3
    hytrogen
    Registered Users, Registered Users 2 Posts: 952 ✭✭✭hytrogen


    It's caused by refraction of ice crystals in the upper atmosphere, like how the water wall on the edge of a rain belt reflects the suns rays to cause a rainbow in a semi circle in the observers direction, because there's no line of horizon apexing the moon it's a complete circle.
    It looked awesome at midnight in Dublin staggering home from the local :P (I did explain it too then)


  • #4
    Brussels Sprout
    Registered Users, Registered Users 2 Posts: 7,834 ✭✭✭Brussels Sprout


    Yes you're right. Thank you. More info here


  • #5
    Labarbapostiza
    Banned (with Prison Access) Posts: 963 ✭✭✭Labarbapostiza


    hytrogen wrote: »
    It's caused by refraction of ice crystals in the upper atmosphere

    If that's true...........why isn't there a white blur covering the entire view of the moon, but instead rings.

    ?


  • #6
    hytrogen
    Registered Users, Registered Users 2 Posts: 952 ✭✭✭hytrogen


    Labarbapostiza wrote: »
    If that's true...........why isn't there a white blur covering the entire view of the moon, but instead rings.

    ?

    There is except they are so small that the obscuring "smudges" are so insignificant due to the vast body of the moon, together with the intense luminosity of its image that it's not observed by the naked eye unless you have a powerful telescope or lens. It's a similar image if you were to see a mirage in the desert or along your car on a hot day due to the heat waves rising through convection.
    The rings are refracted light from the original source of image travelling in a different plain of view to the observer being refracted towards the observer.

    By celestial navigation this is corrected for Dip values in Height of eye, atmospheric pressure & temperature, and velocity of the body which are all tabulated :d


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