A small telescope has an objective lens of focal length 125 cm and an eyepiece of focal length 2 cm. What is the magnification of the telescope? What is the separation between the objective and eyepiece? Two stars separated by 1' will appear at what separation when viewed through the telescope?

Explanation

`f_(o)=125cm,f_(e)=2cm,m=?L=?,theta=?`
Equation for magniification of telescope, `m = (f_(o))/(f_(e))`
Substituting, `m = (125)/(2) = 62.5`
Equation for approximate length of telescope, `L = f_(o) + f_(e)`
Substituting, `L=125+2=127cm=1.27m`
Equation for angular magnification, `m=(theta_(i))/(theta_(o))`
Rewriting, `theta = m xx theta_(o)`
Substituting, `theta_(i)=62.5xx1.=62.5.=(62.5)/(60)=1.04.`