Scope Features II
Choosing the right scope
Eyepiece placement
Another consideration when selecting a spotting scope is eyepiece
placement. Some scope models have eyepieces configured for
straight-through viewing, making it easy to quickly locate and follow a
subject.
Other scope designs have the eyepiece angled at forty-five degrees. This
style makes viewing above the horizon easier, does not need a tall
tripod for use, and makes sharing observations with others more
convenient. Astronomy telescopes usually have the eyepiece angled at
ninety degrees: less convenient for viewing birds.
Eye relief
Eyeglass wearers should pay attention to the amount of eye relief offered by the scope. This refers to the fact that the optics direct the focal point further back behind the eyepiece so the eyeglass wearer can see a complete field of view. Eye relief is given in millimeters in the model's technical specifications. Generally, 12 to 15mm of eye relief is adequate for most eyeglass wearers to be comfortable.
As with binoculars, some scope designs have folding rubber eyecups to accommodate non-eyeglass wearers. Other designs snap up and down, or turn-and-lock into place.
Focusing mechanism
In spotting scopes, focusing is normally done in one of two ways. The focusing collar design has a knurled or rubberized handgrip around the scope barrel, offering convenient rapid focusing. Focus knobs are slower but permit more precise, accurate focusing. Your hand size and dexterity may be an issue here, so try each style to find your preference. The rack-and-pinion focus mechanism found on astronomy telescopes is less rugged.
