AstroFAQs pp 1-23 | Cite as

Choosing Equipment

  • Stephen F. Tonkin
Part of the Patrick Moore’s Practical Astronomy Series book series (PATRICKMOORE)


Two numbers, e.g. 10 × 50 or 11 × 80, designate a binocular. The first of these numbers is the magnification; the second is the diameter of the objective lenses in millimetres. For example, a 7 × 50 binocular has a magnification of ×7 and objective lenses of diameter 50 mm.


Root Mean Square Charge Couple Device Light Cone Rayleigh Criterion Exit Pupil 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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© Springer-Verlag London 2000

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  • Stephen F. Tonkin

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