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Sunrise/Sunset Times

  • 08-05-2009 7:44pm
    #1
    Moderators, Education Moderators, Motoring & Transport Moderators Posts: 7,395 Mod ✭✭✭✭


    My extreme apologies if this is the wrong forum. (I considered Weather or Physics, but I didn't think they were appropriate)

    This site here lists the sunset/sunrise times for Dublin for each day
    http://www.timeanddate.com/worldclock/astronomy.html?n=78

    For example, today, the sunset time is listed as 21:07 and the sunrise time is listed as 05:37.

    My question is: what actually happens at this time? What does this exact time mean? Surely you can't narrow a sunset down to one minute - isn't it not a gradual event.

    Can anyone shed some light on this?
    Thanks


Comments

  • Closed Accounts Posts: 124 ✭✭Breaktown


    I think it's the point when the centre of the Suns disk crosses the horizon.


  • Registered Users Posts: 368 ✭✭backboiler




  • Moderators, Science, Health & Environment Moderators Posts: 3,641 Mod ✭✭✭✭Beeker


    My extreme apologies if this is the wrong forum. (I considered Weather or Physics, but I didn't think they were appropriate)

    This site here lists the sunset/sunrise times for Dublin for each day
    http://www.timeanddate.com/worldclock/astronomy.html?n=78

    For example, today, the sunset time is listed as 21:07 and the sunrise time is listed as 05:37.

    My question is: what actually happens at this time? What does this exact time mean? Surely you can't narrow a sunset down to one minute - isn't it not a gradual event.

    Can anyone shed some light on this?
    Thanks
    I may be wrong but my understanding is it is the time that the leading edge raises above the horizon for sunrise and when the trailing edge dips below the horizon for sunset. Dont forget that sunrise/set times will differ for different parts of the country. The further west you are the later the times will be.


  • Closed Accounts Posts: 911 ✭✭✭994


    My extreme apologies if this is the wrong forum. (I considered Weather or Physics, but I didn't think they were appropriate)

    This site here lists the sunset/sunrise times for Dublin for each day
    http://www.timeanddate.com/worldclock/astronomy.html?n=78

    For example, today, the sunset time is listed as 21:07 and the sunrise time is listed as 05:37.

    My question is: what actually happens at this time? What does this exact time mean? Surely you can't narrow a sunset down to one minute - isn't it not a gradual event.

    Can anyone shed some light on this?
    Thanks
    No, this is a common mistake. Dusk and dawn are the gradual events; sunrise is the moment that the leading edge of the sun becomes visible, sunset is the moment that the trailing edge vanishes.


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