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Re: [ccd-newastro] Uploaded new images

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  • KSBTK@HOME
    Good Morning Ron: An interesting discovery! I am almost afraid to ask how you came up with this method . I presume the t-shirt should be white. Is that
    Message 1 of 8 , Oct 1, 2000
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      Good Morning Ron:

      An interesting discovery! I am almost afraid to ask how you came up with
      this method <g>.

      I presume the t-shirt should be white. Is that correct? Also, can the
      images be taken any time of the day or is toward evening better?

      I will give this a try with the fastar set-up and a dew shield. I'll place
      the image in the files section for your evaluation.

      Clear skies,
      Kevin
      ksbtk@...



      > The best method I've found for flat fielding isn't in that chapter; I
      > discovered it just two days ago. <g> I'll be adding it shortly.
      >
      > I'm not sure, though that it will work with the Fastar. The method
      involves
      > placing a t-shirt over the front of the scope. With a conventional setup,
      > you can simply stretch the t-shirt across the opening. You then take a
      > daylight images with a very short duration, maybe 4-6 of them, average
      them,
      > and you have a superb flat field.
      >
      > It's worth a try with the faster setup, but the problem may be that the
      > shirt can't be easily stretched flat because of the camera sticking out.
      If
      > you have a dew shield, it would be worth a try, but if you don't use the
      dew
      > shield when imaging, it might give you a flat that won't be quite right.
      > This would have to be tested to find out.
      >
      > Otherwise, I would think that a twilight flat or a dome flat would be most
      > effective with the Fastar setup.
    • Ron Wodaski
      Yes, a white t-shirt. I have no idea how or why I thought it up; it just seemed like it was worth trying. I really can evaluate the image on its own; what
      Message 2 of 8 , Oct 1, 2000
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        Yes, a white t-shirt. I have no idea how or why I thought it up; it just
        seemed like it was worth trying.

        I really can' evaluate the image on its own; what determines its value is
        how well it works as a flat field on your images.

        Ron Wodaski
        The New Astronomy Book Site - http://www.newastro.com



        -----Original Message-----
        From: KSBTK@HOME [mailto:ksbtk@...]
        Sent: Sunday, October 01, 2000 5:00 AM
        To: ccd-newastro@egroups.com
        Subject: Re: [ccd-newastro] Uploaded new images


        Good Morning Ron:

        An interesting discovery! I am almost afraid to ask how you came up with
        this method <g>.

        I presume the t-shirt should be white. Is that correct? Also, can the
        images be taken any time of the day or is toward evening better?

        I will give this a try with the fastar set-up and a dew shield. I'll place
        the image in the files section for your evaluation.

        Clear skies,
        Kevin
        ksbtk@...



        > The best method I've found for flat fielding isn't in that chapter; I
        > discovered it just two days ago. <g> I'll be adding it shortly.
        >
        > I'm not sure, though that it will work with the Fastar. The method
        involves
        > placing a t-shirt over the front of the scope. With a conventional setup,
        > you can simply stretch the t-shirt across the opening. You then take a
        > daylight images with a very short duration, maybe 4-6 of them, average
        them,
        > and you have a superb flat field.
        >
        > It's worth a try with the faster setup, but the problem may be that the
        > shirt can't be easily stretched flat because of the camera sticking out.
        If
        > you have a dew shield, it would be worth a try, but if you don't use the
        dew
        > shield when imaging, it might give you a flat that won't be quite right.
        > This would have to be tested to find out.
        >
        > Otherwise, I would think that a twilight flat or a dome flat would be most
        > effective with the Fastar setup.





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