Stargazing Why is magnification defined as the ratio of eye and objective lens resolution?

AI Thread Summary
Telescope magnification is often misunderstood; it is defined as the ratio of the focal lengths of the telescope and the eyepiece, not merely the resolution powers of the eye and objective lens. The concept of resolving power lacks a clear definition without context, leading to confusion about its relevance in defining magnification. The discussion highlights the need for clarity in terminology and the importance of precise definitions in optics. References to textbooks like those by Alonso and Finn are suggested for deeper understanding, though accessibility may be an issue for some. Ultimately, a proper grasp of magnification requires distinguishing between focal length and resolving power.
Marketo
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The telescope magnification is given by the measure of the resolution power of the eye divided by the resolution power of the objetive lens. I just want to know why a magnification can be defined as the ratio of these two kinds of resolution, I need a justification of this statement.
 
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xts said:
Where have you found such definition of magnification?
I would also like to see its justification

See: http://en.wikipedia.org/wiki/Magnification

Please check The physics book of Marcelo Alonso and Edward J. Finn in the chapter of geometry of waves when talking about telescope
 
Marketo said:
Please check The physics book of Marcelo Alonso and Edward J. Finn in the chapter of geometry of waves when talking about telescope
Ouch - you are sending me to a library having English science textbooks (it had not been translated to my language, so I won't get it in my local library)... Not this week...
 
Marketo said:
The telescope magnification is given by the measure of the resolution power of the eye divided by the resolution power of the objetive lens. I just want to know why a magnification can be defined as the ratio of these two kinds of resolution, I need a justification of this statement.

It is not defined this way, it is defined as the ratio of focal lengths of the telescope and the eyepiece. Resolving power is not a clearly defined concept unless you also state how you define resolving power, and in any case it makes no sense in this context. Either you misunderstood the text and did not look into it any farther, or the text is making some kind of analogy or stating how (I don't know how) the precisely defined number "magnification" can be stood in terms of resolving power of the two components. I also presume you meant "eyepiece" when your wrote "eye".
 
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