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filmed this star with my camcorder tonight

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  • 19-01-2020 12:33am
    #1
    Registered Users Posts: 11,718 ✭✭✭✭


    I saw a bright tiny star in the sky on a frosty clear night and decided to test the zoom on a Panasonic v380 camcorder on a setting of 3000x zoom (the camcoder native would be 57x optical zoom so the rest is done by digital zoom, most probably why it was pixelly at full zoom)
    Anyway here is the result I got.

    Is that really a shape of a star or is it just the camcorder picking up its shape wrong because it was so far away?

    and what about colours? are they near enough a representative of real colours rather than what looks from the ground is a twinkly bright white colour?

    my compass on my mobile phone tells me the star was 186' South
    Location County Sligo.



Comments

  • Moderators, Recreation & Hobbies Moderators Posts: 16,287 Mod ✭✭✭✭quickbeam


    What time was it taken? The brightest "star" at the moment is likely to be Venus.


  • Registered Users Posts: 22,233 ✭✭✭✭endacl


    Most likely Venus. Also, the colours (and shape) are artefacts induced by the extreme (I presume digital, not optical) zoom. To paraphrase Blackadder when commenting on Lord Percy’s forays into alchemy, “what you have there, Andy, is some ‘green’”.


  • Registered Users Posts: 11,718 ✭✭✭✭Andy From Sligo


    quickbeam wrote: »
    What time was it taken? The brightest "star" at the moment is likely to be Venus.

    10.27pm


  • Registered Users Posts: 22,233 ✭✭✭✭endacl


    Not Venus then.


  • Closed Accounts Posts: 3,502 ✭✭✭q85dw7osi4lebg


    Looks like Sirius


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  • Registered Users Posts: 22,233 ✭✭✭✭endacl


    Looks like Sirius

    Looks nothing like Sirius! Greeny-purpley blob?


  • Registered Users Posts: 22,233 ✭✭✭✭endacl




  • Closed Accounts Posts: 40,061 ✭✭✭✭Harry Palmr


    Looks like special effects from a 1960s Soviet science fiction film, both cheap and sort of beguiling.


  • Closed Accounts Posts: 3,502 ✭✭✭q85dw7osi4lebg


    To the naked eye Sirius is like a kaleidoscope of rainbow colours most nights in winter


  • Closed Accounts Posts: 1,030 ✭✭✭Boredstiff666


    If you look at that star with the naked eye strange things can happen to you and by tomorrow you will be .......


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  • Closed Accounts Posts: 3,502 ✭✭✭q85dw7osi4lebg


    If you look at that star with the naked eye strange things can happen to you and by tomorrow you will be .......

    Naked ?


  • Closed Accounts Posts: 1,030 ✭✭✭Boredstiff666


    Naked ?

    Amongst other things.


  • Registered Users Posts: 1,589 ✭✭✭ps200306


    Is that really a shape of a star or is it just the camcorder picking up its shape wrong because it was so far away?

    and what about colours? are they near enough a representative of real colours rather than what looks from the ground is a twinkly bright white colour?

    my compass on my mobile phone tells me the star was 186' South
    Location County Sligo.


    To properly figure out what you were looking at needs altitude (height above the horizon) as well as azimuth (direction around the horizon) plus date, time and location. The stars move one degree west every four minutes, and one degree west each night if viewed at the same clock time. I'll hazard a guess you were looking at Rigel, Orion's right knee. It was at 189° azimuth at 22.27 last night. Bellatrix (Orion's right shoulder at 187° and 15° higher altitude) is almost identical in colour and actually closer to the direction you reported but more than three times fainter, so I'll guess you went for the brighter one:

    f4ApvY6.png?1

    It is genuinely blue, T=11000K, colour index B-V = -0.03, which you can roughly read off the diagram:

    UX1FRt7.png?1

    On a frosty night at low altitude the atmosphere makes a mess of the image. It flashes and jumps around through twinkling, and changes colour because of refraction. But I would guess much of the mess is due to your camera optics and sensor. It's nothing to do with distance. Stars don't have a shape. They are always too far away to be anything but a point. Any optical system will turn it into a small disc consisting of concentric rings, by diffraction. But what you're seeing is much more likely to be bleedover across pixels in your sensor.


  • Registered Users Posts: 1,253 ✭✭✭Oops!


    In north Tipp here looking directly south just now... Crazy bright almost flashing light in the sky... Anybody know what it is?


  • Registered Users Posts: 1,589 ✭✭✭ps200306


    Oops! wrote: »
    In north Tipp here looking directly south just now... Crazy bright almost flashing light in the sky... Anybody know what it is?
    Sirius is directly south at that time, 20 degrees above the horizon. It's the brightest star in the sky. It's flashing because it's so low (high air mass). You may also see it flashing different colours, usually red and green.


  • Registered Users Posts: 1,253 ✭✭✭Oops!


    ps200306 wrote: »
    Sirius is directly south at that time, 20 degrees above the horizon. It's the brightest star in the sky. It's flashing because it's so low (high air mass). You may also see it flashing different colours, usually red and green.

    Yes flashing red and green, almost like jets i'm used to seeing from where i live at around 10k feet heading for Shannon but just not moving!


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