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Old 22-07-2012, 09:02 PM
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Globular3 (Jeff)
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Join Date: Aug 2007
Location: Sydney, Australia
Posts: 47
Object Size in FOV

Hello,

I'm thinking about getting some new astro equipment and was wondering if anyone can help with these questions.

Q1) Does the angular size of an object in the field of view (FOV) of the eyepiece appear the same at equal magnifications BUT with different objective lens sizes of telescopes? For example, would Saturn (or any astronomical object) appear the same size at say 140x in a 70mm telescope and 140x in a 100mm telescope?

Q2) Does the angular size of an object in the FOV depend on what eyepiece is used? For example, if I used say a Televue Delos 8mm eyepiece to get the 140x with the 70mm telescope, would Saturn look bigger than it would in a Plossl 8mm eyepiece at 140x in the same 70mm telescope?

Thanks for any enlightenment anyone could give me here. As astro equipment can be potentially very expensive, I'd like to know what difference (if any) there is so I can make an informed choice.
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