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Old 16-04-2011, 12:06 PM
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Satchmo
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Join Date: Dec 2005
Location: Sydney
Posts: 1,883
Hi Steven

For an F5 scope the light drop off is fairly gradual. A 6mm fully illuminated field is standard if you want to minimise your central obstruction. A 1/12 wave Antares should be adequate . The optical system is only good as its weakest link- so I assume your mirror star tests well and is worth pursuing a smaller central obstruction.
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