Consider the following statements about a refracting astronomical telescope used in normal adjustment (final image at infinity). Which of the statements are correct?

• I. The distance between the objective and the eyepiece equals f_o + f_e.
• II. Its magnifying power is f_o/f_e, so the objective should have a much larger focal length than the eyepiece.
• III. Increasing the diameter of the objective (keeping its focal length unchanged) increases the magnifying power.
• IV. The final image seen through the telescope is erect.