Sky Rover Optics 0.8x Reducer for 90GPS (Sky Rover Optics, SKU: 25644) is a dedicated focal reducer designed for astrophotography with the Sky Rover 90GPS f/6 telescope. It reduces the instrument’s focal length from 540 mm to 432 mm and changes the focal ratio from f/6 to f/4.8, providing a wider field of view and increasing the amount of light reaching the sensor per unit of time. The four-element optical system contains lanthanum-glass lenses and produces a 45 mm image circle suitable for use with full-frame cameras.

Key features

• design developed specifically for the Sky Rover 90GPS f/6 telescope
• 0.8× reduction factor, resulting 432 mm focal length and f/4.8 focal ratio
• optical system consisting of four lenses in four groups, including lanthanum-glass elements
• 45 mm image circle suitable for full-frame sensors
• built-in sensor-plane tilt adjustment mechanism
• integrated CAA mechanism allowing adjustment of the camera angle
• M82 × 1 thread on the telescope side and M54 × 0.75 thread on the camera side
• 55 mm backfocus with an adjustment range of ±2.5 mm
• included 2" extension tube allowing the reducer to be correctly installed on the 90GPS telescope

Set contents

• Sky Rover Optics 0.8x Reducer for 90GPS
• 2" extension tube
• aluminium front protective cover
• aluminium rear protective cover

Technical specifications

• manufacturer: Sky Rover Optics
• manufacturer’s product name: Specialist 0.8x Reducer for 90GPS
• SKU: 25644
• type: dedicated focal reducer for astrophotography
• compatible telescope: Sky Rover 90GPS f/6
• reduction factor: 0.8×
• optical design: 4 lenses in 4 groups, including lanthanum-glass elements
• telescope focal length without the reducer: 540 mm
• telescope focal length with the reducer: 432 mm
• telescope focal ratio without the reducer: f/6
• telescope focal ratio with the reducer: f/4.8
• image-circle diameter: 45 mm
• supported sensor format: full frame
• telescope-side thread: M82 × 1
• camera-side thread: M54 × 0.75
• backfocus: 55 mm
• backfocus adjustment range: ±2.5 mm
• mechanical adjustment: tilt mechanism and CAA
• overall dimensions: 154.3 × 104 mm
• main-body dimensions: 102.3 × 104 mm
• extension-tube dimensions: 52 × 104 mm
• total net weight: 1492 g
• main-body weight: 1370 g
• extension-tube weight: 122 g
• front and rear cover material: aluminium alloy

The dedicated optical design, full-frame sensor coverage and camera tilt and position adjustment allow the Sky Rover 90GPS telescope to be configured for wide-field astrophotography at an f/4.8 focal ratio.