It doesn't have "APO" on the scope. I bought it used, and don't know. I looked it up and APO is aperchromatic lens. Here is what I found on Optics Planet:
"These
Kowa 77mm High Performance Prominar TSN-770 Series spotting scopes feature large, oversized objectives. Indeed, this
spotting scope "eye" sets the
Kowa TSN-770 Spotting-Scope apart from the competition. For birders and hunters alike, the
Kowa TSN-770 spotting scope redefines clarity with its large
Kowa 77mm objective lenses crafted to
Kowa's exacting standards for resolution and contrast. Add
Kowa's new
C3 fully multi-coated lens coating system and you have performance that must be seen to be appreciated."
The scope has a clear and bright image. I have had no problems with it.