Reducer / corrector 0.77x for Esprit 150ED

Owners of the Esprit 150ED apochromatic refractor can now image with a reduced focal length. Although the nominal f/7 focal ratio is not excessive, it's always appreciated to be able to reduce exposure times or increase the signal-to-noise ratio (the focal ratio then becomes f/5.4).

Characteristics

• Resulting focal ratio (with Esprit 150ED): f/5.4
• Number of lenses: 3 (FMC - Fully Multi Coated multi-layer treatment)
• Backfocus: 55mm
• Corrected image circle (for APS-C): 34mm
• Female thread for 2" filter: Included
• Thread (camera side): M48x0.75
• Thread (telescope side): M74x1