JMI EV2NM EV-2n (Newtonian) Event Horizon Focuser, 2" with motor
Item No. 765-61305
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Manuf. No. JMI EV2NM
Event Horizon EV-2nM is a motorized 2" black-anodized aluminum focuser with rubber grip knobs that lifts up to 8 pounds, twice the weight of the EV-3n.
Newtonian version mounts onto a range of surfaces, from a tube that is 7.25" diameter or larger, to a flat surface.
Zero image shift, zero backlash, with tolerances that are 100X better than rack-and-pinion focusers! What is the Event Horizon Focuser?
The Event Horizon Focuser (EV) is a low-profile, friction-drive focuser designed for both the amateur and professional market. The highly acclaimed Crayford design (see below) permits tolerances up to 100 times better than conventional rack-and-pinion focusers. Zero image shift and zero backlash makes it fantastic for visual and photographic work and a must for CCD imaging. The modular design makes changes and upgrades extremely easy to accomplish. Add the optional Smart Focus, Digital Read Out (DRO) or Digital Focus Counter (DFC), for the ultimate focusing system. The EV is truly a masterpiece of engineering and workmanship that you will be proud to own for years to come.
What is the Crayford Design?
The Crayford Eyepiece Mount (CEM) was invented by John ("Jack") Wall. The Crayford name comes from the Crayford Manor House Astronomical Society (UK) to which he belongs. The Crayford design uses high pressure on a metal drive shaft pressing against a 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.
JMI recognized the benefits of this design and was the first company to bring it to the amateur market in a commercial product.
Event Horizon EV-2...
The Event Horizon EV-2 is a 2" black-anodized aluminum focuser with rubber grip knobs. The focuser lifts up to 8 pounds. Manual control is over 1ý times finer than most rack-and-pinion focusers.
The motorized Newtonian version mounts on a range of surfaces from a 7.25" diameter, or larger, tube to a flat surface. The focuser gives 1/2" of travel and is designed for fine focus after rough adjustment with the normal telescope focusing knob.
- Part Number: 2nM
- Telescope-Specific Design: Newtonian/Generic
- Inside Diameter of Drawtube: 2"
- Body Style: Modular, Black Anodized Aluminum
- Interchangeable Base? Yes
- Combination Base (for surfaces from specified radius curve to flat): 3.625"
- Drive Speed: Single. 0.58" of Travel per Revolution of Knob
- Knobs: Rubber Grip Knobs
- Vertical Load Capacity: 8 lbs.
- Integral Miniature Motor: Included
- Locking Drag Brake: Yes
- Drawtube Bearings: Sealed Stainless Steel Ball
- Drive Shaft Bearings: Sealed Stainless Steel Ball
- Drive Shaft Pusher Bearings: Sealed Stainless Steel Ball
- Drawtube Size: 3"
- Drawtube Compression Ring: Yes
- Maximum Extension: 4.0"
- Minimum Height: 2.19"
- Drawtube Travel: 1.81"
- Maximum Penetration: 1.41"
- Mounting Hole Spacing (Square Configuration): 2.75"
- Output Adapter Included: 1.25" Eyepiece Adapter