Our family enjoys stargazing with our telescope, a gift from my grandfather, when we go camping.
Identify the nonessential appositive phrase.
a gift from my grandfather
our family
with our telescope
when we go camping
An appositive phrase "renames" a noun: here the telescope is being "renamed" as "the gift from my grandfather", and this is also the nonessential appositive phrase. (as in: it can be left out!)