I Have A Math Question

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Refractordude
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I Have A Math Question

#1

Post by Refractordude »


How can I tell what is the apparent/subjective field of view with these numbers? Right click the image. Thanks
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Ruud
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Re: I Have A Math Question

#2

Post by Ruud »


The Angle of View in the screenshot is the true field. It is 7.5°.

If the magnification is 7x,  the apparent field of view is  7 x 7.5°  = 52.5° (like a Plössl eyepiece)
If the magnification is 8x,  the apparent field of view is  8 x 7.5°  = 60°    (like a wide field eyepiece)
If the magnification is 10x, the apparent field of view is 10 x 7.5° = 75°    (almost as wide as a Nagler eyepiece)

HTH
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KathyNS Canada
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Re: I Have A Math Question

#3

Post by KathyNS »


Insufficient data. The two ratios (393.7:3000 and 131.2:1000) and the angle (7.5 degrees) are all saying exactly the same thing: the true field of view (TFOV). To calculate the apparent field of view (AFOV), you also need the magnification, which is not given.

If we are talking avout 7x binos, the AFOV would be 7x 7.5 = 52.5 degrees. If the magnification is 10x, it would be 10x 7.5 = 75 degrees.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
Refractordude
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Re: I Have A Math Question

#4

Post by Refractordude »


Ruud wrote: Wed Nov 18, 2020 8:37 pm The Angle of View in the screenshot is the true field. It is 7.5°.

If the magnification is 7x,  the apparent field of view is  7 x 7.5°  = 52.5° (like a Plössl eyepiece)
If the magnification is 8x,  the apparent field of view is  8 x 7.5°  = 60°    (like a wide field eyepiece)
If the magnification is 10x, the apparent field of view is 10 x 7.5° = 75°    (almost as wide as a Nagler eyepiece)

HTH
Got it and thanks
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