1. A reflecting telescope with the mirror slightly tilted to throw the image to the side where it can be viewed
   - off-axis reflector

Type of: reflecting telescope, reflector

• action spectrum
• action stations
• action-packed
• actionable
• actioner
• Actitis
• Actitis hypoleucos
• Actitis macularia
• Actium
• Activase
• activate
• activated
• activated carbon
• activated charcoal
• activating
• activating agent
• activation
• 39th
• 3d radar
• 3rd
• 3rd October Organization
• 3TC
• 4
• 4-dimensional
• 4-hitter