| Focusers | ||
| ARCTURUS FOCUSERS | Not all focusers are equal. The most common telescope focuser of all is the rack and pinion focuser. It gets its name from the rack of small gear teeth which run along the spine of the drawtube which move it in and out using pinion gears connected to the focus knob. some applications require an even finer focus than ordinary focusers will allow - like planetary viewing and astrophotography require an even finer focus than ordinary focusers can normally give. microfocuser has an additional set of even smaller teeth on the rack to allow even for finer adjustment.Some telescopes use a system called the Crayford focuser. The Crayford focuser doesn't use gears to move the drawtube - it works on roller bearings. The tube is moved by a roller and is carried along by user adjustable pressure bearings. The system was meant to eliminate backlash that can sometimes be found in inferior rack and pinion models. Like the microfocuser, the Crayford also has two "speeds" - one for coarse adjustment and the other for fine focus. Some of our focusers are able to be controlled digitally, sense and account for temperature differences and/or carry huge weight loads. Electric focuser add-ons can virutally eliminate vibration caused by touching the focuser knob. |