TESTAR HELICAL FOCUSER FOR FINDERSCOPES BF25-ZWO all with the single push

all with the single push of a button

Optical length 28 mm Clear aperture

The field flattener and reducer can be screwed directly onto the focuser of the Evostar once the final ring on the focuser tube is removed

No barlow lenses or focusing elements included

5Å with detents at every 0

TESTAR HELICAL FOCUSER FOR FINDERSCOPES BF25-ZWO all with the single pushThe Testar Helical Focuser for Finderscopes allows you to easily convert your straight through Sky Watcher finderscope into a proper guidescope, without the need to modify anything. All you need to do is unscrew the rear eyepiece section and replace it with this. The helical focuser is non rotative, so your cables to not get twisted as you focus. This is the only helical focuser on the market designed specifically for straight through finder scopes