Key Specifications • Optical System: Refractor (Achromatic Lens) • Aperture: 90mm (3.54 inches) • Focal Length: 700mm • Focal Ratio: f/7.7 • Mount Type: Typically paired with an Alt-Azimuth (AZ) Mount or Equi-axial mount for smooth manual tracking. • Primary Uses: Observing craters on the Moon, surface details of Mars, Jupiter's moons and cloud belts, Saturn's rings, bright star clusters, as well as terrestrial/daytime viewing with an erecting prism.