All about the Crayford 50.8mm Kepler for Newton 300mm

Focus is a crucial element in obtaining the best images with a Newton, especially for short focal lengths and imaging. To facilitate focusing, Kepler offers a Crayford-type model with microfocuser (1/10th reduction) adaptable to many Newtons 300mm in diameter. It has a load capacity of 2.7kg to support large eyepieces, a ccd camera or an APS-C format APN.

This is an "upgrade", a significant improvement if your telescope does not have a fine, geared-down focuser at the base. For observations at high magnifications (planetary, lunar) it is an essential plus as the desired precision is important. If it brings a plus in imaging, a motorized solution will however be recommended (so as not to touch the tube is to induce vibrations).

At the level of the fixing on your optical tube, check that the holes present (center distance) are separated vertically by 73mm and horizontally by 70mm. Otherwise make new holes, symmetrically with respect to the optical axis. Each model has a 50.8mm neck with a 31.75mm reducer. A screw allows the adjustment of the hardness of the Crayford, the greater the load, the more the tension of the knurled screw prevents the slippage of the sliding tube. Another screw allows complete blocking (when you have found the right focus).

Features

•     Focus: Crayford type with 10:1 reduction
•     Load capacity: 2.7kg
•     Construction: Aluminum and steel
•     Hole spacing: 73mm vertically and 70mm horizontally
•     Mechanical back-focus: 73mm (minimum eyepiece height 50.8mm retracted)
•     Sliding tube: 35mm stroke
•     Slider: 50.8mm with 31.75mm reducer (ring clamp)
•     Weight: about 730g

Items delivered

•     1 Crayford 50.8mm Kepler focuser for Newton 300mm
•     1 reducer 50.8mm to 31.75mm (ring clamp)