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Re: [William Optics] Re: 2 inch optics

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  • Scott Walker
    It should be also mentioned that to avoid vignetting in a 32mm Plossl 1.25 inch eyepiece one needs a 2-inch diagonal. This is because the light path widens as
    Message 1 of 1 , Jun 30, 2007
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      It should be also mentioned that to avoid vignetting in a 32mm Plossl 1.25 inch eyepiece one needs a 2-inch diagonal. This is because the light path widens as it gets closer to the objective. The faster the scope the more difference this makes.
       
      Scott Walker 
      ----- Original Message -----
      From: Greg
      Sent: Saturday, June 30, 2007 10:46 AM
      Subject: [William Optics] Re: 2 inch optics

      The reason for going to 2 inch optics is to increase the true field of
      view available. A good example of this are the typical 32 mm and 40 mm
      Plossl. Both are 1.25 inch eyepieces but the 32 mm has a 50 degree
      apparent filed of view while the 40 mm has a 42 degree apparent field
      of view. Both have the same true field of view because the 1.25 inch
      light path is limiting it. Any wider true field requires a 2 inch
      light path. With a 2 inch light path the true field limit it reached
      by eye pieces like the 31 mm Nagler and 41 mm Panoptic.

      --- In William-Optics@ yahoogroups. com, "keepers80" <jlutkin@... > wrote:
      >
      > As an amateur new to the game could I pose a question?
      > "2 inch diagonals and eyepieces are over weight, over priced, over
      > hyped and provide no overall advantage over 1.25 inch optics for
      > either visual or photographic purposes"? Please discuss.
      >

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