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Thread: APOW: Astronomy Picture Of the Week

  1. #1
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    Default APOW: Astronomy Picture Of the Week

    This was taken last night looking north to Williams Lake. Over the years the city and the mills have installed thousands of street and yard lights, many of them sodium vapour. When the night started it was very clear and there was almost no sky glow even in the direction of town so I set up for an all night time lapse sequence similar, but longer, than the one I made recently.

    As is often the case not long after I started taking frames clouds began to move in. In this case they came in from the northwest over the town first and are strongly illuminated by the mixture of mercury vapour and sodium vapour lighting. While it spoiled my time lapse session to some degree I did get an interesting contrast of colours between the night sky and the clouds.

    I wonder how long it will take for those responsible for the design of lighting to realize that lighting up the sky is a total waste of energy?

    Last edited by Evan; 05-20-2009 at 12:55 PM.
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  2. #2
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    Question

    Evan,

    doesn't the camera have to rotate so the stars look stationary in your timelapse photos? if so, how come the trees aren't blurred?

    you do take some cool photos!

    andy b.

  3. #3
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    Default

    It's a fairly wide angle lens and the exposure is only 40 seconds. With that lens it isn't enough time for the stars to show trails.
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  4. #4
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    When I first bought my house in Bolton, MA, in 1982, when I came home at night it was DARK and I had trouble finding the porch stairs. When I sold the place in 2007, it was so light in the sky at night you could see to walk around easily.

    It's a big loss. In 1986 I went to Ayers Rock in Australia, and at night a multitude of stars came down to the horizon. An awe-inspiring sight.
    ----------
    Try to make a living, not a killing. -- Utah Phillips
    Don't believe everything you know. -- Bumper sticker
    Everybody is ignorant, only on different subjects. -- Will Rogers
    There are lots of people who mistake their imagination for their memory. - Josh Billings
    Law of Logical Argument - Anything is possible if you don't know what you are talking about.

  5. #5
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    Default Free

    Cosmic Energy is free i heard evan.

  6. #6
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    Yes it is Mike. I will be posting about that soon. I am still collecting performance data.
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  7. #7
    tony ennis Guest

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    I wonder how long it will take for those responsible for the design of lighting to realize that lighting up the sky is a total waste of energy?
    As soon are their compensation is based upon energy conservation.

  8. #8
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    Evan,

    Nice complementary colors, with the bluish night sky and the orange-tinged clouds.

    I imported your photo into Elements and blew it up 32X to see the pixels as squares. The star colors really become apparent at this magnification. What causes the different colors?
    Allan

  9. #9
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    The color is an indicator of the age of the star. As fusion proceeds up through the elements the color of the star changes to reflect the spectographic lines of those elements. Young stars are fusing hydrogen and that produces copious amounts of high energy photons in the blue end of the spectrum. Old stars are green as they are loaded with iron and iron plasma gives off strong green lines. Red stars are old stars that are expanding, cooling off and no longer fusing so they are radiating according to their black body temperature as they expand.

    Give me a few minutes to find one and I will post a picture that really shows the different colors.
    Last edited by Evan; 05-21-2009 at 12:49 AM.
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  10. #10
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    Here is a good example. It's short exposure but at high magnification with no drive on so the stars formed trails. The scope was very slightly out of focus which actually enhances the colour by expanding the area for the eye to see.

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