Approximation. › Forums › Computing › Angular Resolution of a Telescope › Approximation. 13 December 2020 at 4:05 pm #583554 Dr Paul LeylandParticipant You give the accurate (and correct) procedure. For a decent approximation I just divide 140 by the aperture in mm, which gives an answer which is “good enough”. In your case 140/102 = 1.37. Easy to remember.
