ISO 14490-1:2005 specifies the test methods for the determination of the following basic characteristics of telescopic systems and observational telescopic instruments:

• angular magnification;
• entrance pupil diameter;
• exit pupil diameter and eye relief;
• angular field of view in the object space;
• angular field of view in the image space;
• angular field of view in the object space for spectacle wearers;
• collimation of the bundle of rays emergent from the eyepiece;
• image rotation;
• closest distance of observation.