Calculating Telescope Magnification:

 (Yes, you ARE expected to calculate the magnification of the telescope you are using.)

Here is how to do it.
1) Read chapter six in your textbook
2) Refer to my webpage under "Calculating Telescope Magnification"
3) After you have done that, you should understand that telescope magnification is extremely simple to obtain.  Read below:

Just divide the focal length of the telescope by the focal length of the eyepiece being used. 

How do you find the focal length of the telescope?  First, you need to be able to read.  Assuming that is true, look on 
the front of the telescope ­ it's printed in plain view.  You can ask one of the lab assistants at the observatory, but if this
semester is like previous semesters, they won't have a clue!

If you happen to be working with a telescope that you cannot easily see the front (such as the big telescope in the dome), 
here is all you need to know:

   Telescopes at Stargazer:
       In the dome
       - Celestron Schmidt-Cassegrain with a 14 inch mirror
       - Focal length of 3910 mm
       - Aperture of F/11

       Smaller telescopes
       - The 6" telescope         FL = 1200 mm (F/8 refractor)
       - The 8" telescope         FL = 2000 mm
       - The 9.25" telescope    FL = 2350 mm
       - The 11" telescope        FL = 2800 mm

Next, simply divide the focal length of the telescope by the focal length of the eyepiece you are using (its printed on the eyepiece!)

In other words:

Magnification = (Focal length of the telescope) / (Focal length of the eyepiece)

If you don't know the telescope focal length, you can work backwards:

The Little Thompson Observatory telescope:
    - Aperture (F-Stop) = f/14 
      - Diameter of the primary mirror = 18 inches
      - Focal Length = F-Stop times diameter of the light collecting area or 
         (14)*(18)*(25.4) mm = 6400.8 mm

You lab assistant may try to tell you that you don't have to calculate magnification.  Educate them!

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