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Widest True Field of View for SCT and EdgeHD Optical Tubes

While presenting values for the widest true field of view (Table 9.4 on page 202), I neglected to include a column for using 2" eyepieces/accessories combined with the optical reducer on the 8 inch and larger SCTs/EdgeHDs.  Additionally, I neglected to point out that the clear aperture of the f/6.3 reducer/corrector is 41mm (1.6").

Additionally, after the book went to print, Celestron released the reducer for the EdgeHD series - an f/7 accessory rather than f/6.3.  The clear aperture is 40mm (1.6") on the reducer for the 8" EdgeHD while it is 60mm (2.3") on the reducer for the 9.25" and 11" EdgeHD.  

This results in the following new values for Table 9.4 on page 202 of the book:

Optical Tube Maximum TFOV with 1.25" eyepiece Maximum TFOV with 2" eyepiece Maximum TFOV with 1.25" eyepiece and reducer Maximum TFOV with 2" eyepiece and reducer
SCT 8" 0.9 1 1.4 1.7
EdgeHD 8" 0.9 1 1.25 1.5
SCT 9.25" 0.75 1.1 1.2 1.55
EdgeHD 9.25" 0.75 1.2 1.1 1.75
SCT 11" 0.6 1 1 1.3
EdgeHD 11" 0.6 1 0.9 1.5

 


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