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Re: A "best" f/number to image?

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  • blandp11
    Because the NexImage uses a CCD device with 5.6um pixels, f/20 in any telescope will just meet the Nyquest sampling rate for the camera. You may want to go a
    Message 1 of 6 , May 1 4:48 AM
      Because the NexImage uses a CCD device with 5.6um pixels, f/20 in any
      telescope will just meet the Nyquest sampling rate for the camera.
      You may want to go a bit longer as the Bayers mask increases the
      effective pixel size of the NexImage. I'll post the derivation of
      this number if you are interested, I wrote it up on a post on
      CloudyNights and I'll dig it out.

      Philip

      --- In neximage@yahoogroups.com, "gstrumol" <gstrumol@...> wrote:
      > I've been wondering about what is the "best" f number to take photos
      > at, and would like your thoughts. Here is the issue as I see it (and
      > I may be totally wrong).
    • rightquiet@aol.com
      Thanks Philip - since you ve done the calculations, (grin) what about f-30? ( I need that to get nice-sized planetary images with my little AP 130 f-6.) Does
      Message 2 of 6 , May 1 5:45 AM
        Thanks Philip - since you've done the calculations, (grin) what about f-30? ( I need that to get nice-sized planetary images with my little AP 130 f-6.) Does going too long create imaging problems?
        Peter
        NYC
         
        In a message dated 5/1/2006 7:49:44 AM Eastern Daylight Time, blandp11@... writes:
        Because the NexImage uses a CCD device with 5.6um pixels, f/20 in any
        telescope will just meet the Nyquest sampling rate for the camera.
        You may want to go a bit longer as the Bayers mask increases the
        effective pixel size of the NexImage.  I'll post the derivation of
        this number if you are interested, I wrote it up on a post on
        CloudyNights and I'll dig it out.

        Philip
         
      • William Hamblen
        Because the pixels are square, you d need f/28 diagonally. :)
        Message 3 of 6 , May 1 6:54 AM
          Because the pixels are square, you'd need f/28 diagonally. :)

          rightquiet@... wrote:
          > Thanks Philip - since you've done the calculations, (grin) what about
          > f-30? ( I need that to get nice-sized planetary images with my little
          > AP 130 f-6.) Does going too long create imaging problems?
          > Peter
          > NYC
          >
          > In a message dated 5/1/2006 7:49:44 AM Eastern Daylight Time,
          > blandp11@... writes:
          >
          > Because the NexImage uses a CCD device with 5.6um pixels, f/20 in any
          > telescope will just meet the Nyquest sampling rate for the camera.
          > You may want to go a bit longer as the Bayers mask increases the
          > effective pixel size of the NexImage. I'll post the derivation of
          > this number if you are interested, I wrote it up on a post on
          > CloudyNights and I'll dig it out.
          >
          > Philip
          >
          >
        • rightquiet@aol.com
          In a message dated 5/1/2006 10:05:32 AM Eastern Daylight Time, wrhamblen@comcast.net writes: Because the pixels are square, you d need f/28 diagonally. :)
          Message 4 of 6 , May 1 8:47 AM
            In a message dated 5/1/2006 10:05:32 AM Eastern Daylight Time, wrhamblen@... writes:
            Because the pixels are square, you'd need f/28 diagonally.  :)
            Thanks, very much ... I think. You are being serious, right? Does the :) symbol mean you are joking, or being friendly?
             
            Peter
            NYC
          • gstrumol
            That would be great. What could we search in Cloudy Nights to pull the article up? Gary ... photos ... (and
            Message 5 of 6 , May 1 4:20 PM
              That would be great. What could we search in Cloudy Nights to pull the
              article up?

              Gary

              --- In neximage@yahoogroups.com, "blandp11" <blandp11@...> wrote:
              >
              > Because the NexImage uses a CCD device with 5.6um pixels, f/20 in any
              > telescope will just meet the Nyquest sampling rate for the camera.
              > You may want to go a bit longer as the Bayers mask increases the
              > effective pixel size of the NexImage. I'll post the derivation of
              > this number if you are interested, I wrote it up on a post on
              > CloudyNights and I'll dig it out.
              >
              > Philip
              >
              > --- In neximage@yahoogroups.com, "gstrumol" <gstrumol@> wrote:
              > > I've been wondering about what is the "best" f number to take
              photos
              > > at, and would like your thoughts. Here is the issue as I see it
              (and
              > > I may be totally wrong).
              >
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