Crossword Puzzle Telescope?

Clue: Telescope?

Home of the world's largest refracting telescope (YERKESOBSERVATORY with 17 letters)
___ Optics (telescope maker) (CSTAR with 5 letters)
Telescope pioneer's last name (GALILEI with 7 letters)
Hubble Telescope part (LENS with 4 letters)
Green Bank Telescope user (RADIOASTRONOMER with 15 letters)
Small telescope (SPYGLASS with 8 letters)
A telescope may be trained on one (ORB with 3 letters)
Elements in telescopes (LENSES with 6 letters)
Telescope measure (FOCALLENGTH with 11 letters)
Telescope pioneer (GALILEO with 7 letters)