JMI EV3-N Standard Event Horizon Telescope Focuser - Newtonian Base

A masterpiece of engineering and workmanship, the JMI Dual-Speed Event Horizon Telescope Focuser is a low-profile, friction-drive focuser designed for the discriminating astronomer.

The highly acclaimed Crayford design uses pressure on a metal drive shaft pressing against a machined metal drawtube which is held by bearings on the opposing side. This direct surface-to-surface drive mechanism eliminates backlash and shifting of the drawtube as seen in other designs such as the rack-and-pinion focuser, and allows for very fine adjustments. Zero image shift and zero backlash makes this focuser fantastic for visual and CCD imaging (even better for imaging is our EVRZ versions).

Take the frustration out of focusing your telescope!

• Single speed friction drive
  
• Compression ring (for secure mar-free holding of eyepieces and cameras)
• ZERO image shift
  
• Friction drive for backlash free focusing
• CNC Machined Crayford Design
  
• Draw tube length of travel is configurable at the time of purcase (see drop down menu)
• Compatible with Newtonian telescope tubes from 7.25″ diameter or larger as well as flat focuser boards  
• Weight: 1.4 pounds
• Load Capacity: 4 pounds
  
• Individually assembled and tested in our own facility
• 100% Made in USA

Note: Fitting a new focuser onto an existing telescope takes careful consideration and engineering.  This is not a one size fits all solution.  There are many publicly available software tools available to help with this, have a look around on the internet forums for more guidance.

Optional Optical Adapters:

• Select JMI Combination 1.25-inch Eyepiece and T-Thread Adapter, ADPT2-1.25T for camera use. JMI Adapter for mounting a CCD or other camera, with a standard T-thread, into a 2" drawtube. It also doubles as a 1.25" adapter. A T-adapter holds a CCD camera more securely than a standard 1.25" adapter. The adapter uses a compression ring to secure inserted equipment. It includes standard 48mm filter threads on the other end of the adapter (inserted into focuser end).
• Select Farpoint 2 Inch Focuser to 1.25 Inch Eyepiece Adapter, FAV100 for a visual 2" to 1.25" eyepiece adapter. Farpoint 2 Inch Focuser to 1.25 Inch Eyepiece Adapter features a non-marring compression ring for precise centering of telescope eyepieces. Threaded for both 2 inch and 1.25 inch filters and has a stop to prevent long eyepieces from damaging filters.