Will you be or mostly using it near a car? Do you plan on taking photos through the lens?
: Look for models labeled with ED (Extra-low Dispersion) or HD (High Definition) glass. This specialized glass minimizes "chromatic aberration"—that purple or green fringing seen around dark objects against light backgrounds.
: The eyepiece is set at a 45-degree angle. This is generally preferred for wildlife viewing because it allows for comfortable sharing between people of different heights and is much easier for looking up at birds in trees or on cliffs.
: Prioritize a 65mm ED scope with an angled body for a balance of weight and performance.
: Ensure the scope is O-ring sealed to prevent rain and splashes from entering the housing.