For more than a decade, the Astra IIIb sextant has been a favorite of celestial navigators and enthusiasts for four reasons: optical quality, comfort, durability and price. The crystal clear telescope and large mirrors collect ample light for star sights. Three horizon and four index shades permit a good range of density combinations for sun sights. The sturdy aluminum alloy frame is heavy enough to be stable, yet light enough for shots that may require a little patience. The handle is well centered. Safety secured and shipped in a solid wood carry case.
Telescope: 3.5 x 40
Field of View: 5 degrees
Objective aperture: 40mm
Resolving power: 8.75 in.
Diameter of exit pupil: 11mm
Measuring range: -5 degrees to +130 degrees
Accuracy, +20 in.
Horizon shade glasses: 3
Index shade glasses: 4
Temperature range: -30 to +50 degrees C.
Net weight: 2.65 lbs.
Lamp voltage: 3V
Illumination: on both arc and drum.
Overall case size: 12-3/4 in x 11 in x 6-3/4 in.
The Astra IIIb Standard Model has a round index mirror with silvering applied to the rear surface of the glass. The Deluxe model has a rectangular mirror with silvering on its face (added in 1994). The new mirror configuration is somewhat interchangable with other sextant mirrors.
You may upgrade the mirror of the Astra IIIb Standard model to the mirror of the Astra IIIb Deluxe model with the optional mirror upgrade kit. Email email@example.com for pricing.