An astronomical refracting telescope at an observatory is in normal adjustment. The distance between the objective lens and the eyepiece lens is 12.0 m12.0\text{ m}12.0 m, and the angular magnification is 499499499.
Calculate the focal length of the eyepiece lens. Give your answer to an appropriate number of significant figures.
The telescope is used to inspect a binary star system. Compare the advantages of using a charge-coupled device (CCD) with direct observation using the naked eye at the eyepiece.