hi, a long time ago whilst at college I took a photo of the orbit( or part of ) a planet.

This involved pointing camera at a planet and taking a photo but leaving shutter open for many hours. Could anybody please remind me how to do it, and any settings required, also can it be done with a digital camera? many thanks for helping me with my sons homework. barry

You have to adjust the aperture setting so F15 would be 15 seconds for example, aperture controls the amount of light that reaches a digital camera sensor.