Jump to content

  •  

- - - - -

JMI EV-1NM Focuser


Discuss this article in our forums

This is a two speed Crayford style focuser from JMI. This is a low profile focuser and requires the use of an extension tube to get the correct focal length. It is in the 2 inch format and has a 1.25 inch adapter for smaller lenses.

The focuser arrived in great condition and was packed extremely well. The focuser was basically encased in soft foam. I was hoping to just be able to unscrew my old focuser and replace it with this one, but this is was not the case. The holes in the telescope were off buy just a small amount so I actually had to widen the current holes to get the base plate to attach. Not what I wanted to do, but it actually ended up being easy to accomplish. Once the base plate is screwed onto the telescope I mounted the focuser to the base plate. This is a really nice design because you can actually mount the focuser so that the knobs are anywhere you want them. The base plate also comes with leveling screws. These are used, of course, to level the base plate so the focuser lines up perfectly with the secondary mirror.

The whole unit seems really sturdy and well made. It also looks really sharp! The dual speed knobs are much smoother than the stock ones on my 16” LightBridge. The dial also has numbers so you can see its position. This might be handy for photography use. The lenses slide in real easy and are securely held in place with a ring and thumbscrew setup. The focuser is also rated to lift 8 pounds so it’s plenty strong to hold up a big lens even if it’s equipped with a Barlow. The focuser is so much nicer to use that the stock one. Since there is much finer control there is less time spent bouncing in and out of focus. The tension for the knobs is controlled by just one thumb screw. A motor can also be purchased for this focuser so that you don’t even have to touch the scope to focus, you just press some buttons on a hand controller. This is very handy if you are an astrophotographer.

This is a very welcome upgrade to my 16” LightBridge. Although the stock focuser was nice and definitely functional, this one from JMI is just much better. Not only is this a dual speed Crawford style focuser, it has the ability to be motorized. The feel is noticeably smoother than the stock one and is much more secure. There is also less slop in the knobs. All of this combined makes the viewing experience much more enjoyable.








0 Comments



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics