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Hi Jase
If you take an 8”, 2000mm, F10 SCT and add an F6.3 Reducer/Corrector, you have effectively “zoomed” out to a shorter focal length of 1260mm at F6.3. Therefore, you now have a larger field of view as well as a “faster” ‘scope, and you have simultaneously changed 2 parameters, the FL and the F Ratio.
If you keep the focal length at 2000mm, but change the F Ratio to F6.3, you would now have a 12.5” SCT. That is, 2000/6.3 = 317mm = 12.5 in
Now in this case, the 12.5” F6.3 FL being the same, i.e. 2000mm, the FOV should be the same as the 8” SCT F10, but it will appear brighter at F6.3 than at F10.
The 12.5” SCT will also be able to resolve more detail i.e. split closer double stars due to its larger aperture.
At least that’s how I interpret this.
Cheers
Dennis
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