When it comes to buying a spotting scope, you have various options and choices. People buying spotting scope for the first time normally buy all of the pieces at once. Advanced users on the other hand have a lot more precise wishes for upgrading their spotting scopes. Therefore they prefer to buy certain parts (eyepiece, sports rail, tripod,) afterwards. Since spotting scope consists out of spotting scope body and an eyepiece, users often buy many different eyepieces. It is important to note that one spotting scope body can feature multiple different eyepieces. However it does not go the other way around, since spotting scope body determines eye-piece magnification.
In some rare cases people are looking to buy spotting scope body for a specific eyepiece. But that is only because their spotting scope body is damaged or destroyed, so they need a new one.
Spotting scope body represent a body without an eyepiece. When talking about straight spotting scopes bodies, body is straight at an angle of 0°.
When talking about angled spotting scopes bodies, body is angled at an angle of 45°.
As mentioned before, people normally buy spotting scope body and an eyepiece as separate parts. But when comparing the two, eyepiece is sold way more often than the spotting scope body.
Different types of eyepieces offer diverse characteristics. Some feature
That is why manufactures produce and sell spotting scope body and spotting scope eyepiece as separate parts. As for the angled or straight spotting scopes, the same eyepieces can be used in both categories.