Starfield 2″ Adjustable 0.8x Reducer for 70mm to 90mm Telescopes

End the back focus struggle with the Starfield 2″ Adjustable 0.8x Reducer for 70mm to 90mm Telescopes. This handy reducer makes finding and adjusting back focus easy when connected to the Gar 80 / 90 mm telescope focuser or other compatible telescope with a 2″ focuser.

Starfield 2″ Adjustable 0.8x Reducer for 70mm to 90mm Telescopes

The chart above shows back focus settings and dimensions for this 0.8x reducer. In addition to the listed telescopes, this reducer will work with other telescopes with a 70mm to 102mm aperture.

• 102 mm / focal ratio f/7 – 55 mm
• 90 mm / focal ration f/6 – 56 mm
• 80 mm / focal ratio f/7 – 57.6 mm
• 80 mm / focal ratio f/6 – 59.6 mm
• 70 mm / focal ratio f/6 – 61.6 mm

Achieving the correct amount of back focus is simple, just refer to the chart above. If fine tuning is required, just apply a small twist. When adding accessories such as filter wheels, internal filters, or rotators, simply add up the thickness of all the accessories plus the distance to your sensor and subtract from 61.6. Then you set the reducer to the number you just calculated for perfect back focus.

• Suitable for refractor telescopes from 70mm to 102mm aperture with 2″ focusers
• Filters can be added inside the reducer

• Starfield Adjustable 2″ Reducer for 70 to 90mm Telescopes