Customer Comments

"I just received the EV3N.  Wow, what a beauty."  (D. C.  12/20/2016)

"I now have a dilemma, whether to fit the EV-2cM to my Takahashi Mewlon 180 or should I place it in a glass case on the mantelshelf as a contemporary display of fine American design, engineering and manufacturing.  It is so heartening to see that there are still some organizations producing such elegant, quality, functional and cost effective products after the shocking excesses of the financial institutions of Wall Street and other global financial centres.  If only they had kept the customer in focus as JMI does..."  (D. S.  04/14/2014)

"I just wanted to tell you, I have been an amateur astronomer for 20 years.  I just purchased my 8th focuser from you, the EV-2c for SCT telescopes.  Your quality machining and general design is truly far superior to all the other focusers I have seen and used.  The mega thumbscrew and the ability to have manual or motorized at the turn of a knob is absolutely fantastic.  This is the only rotating focuser I have ever used that rotates super smoothly AND actually stays put even with a very heavy imaging train!  Thank you so much."  (M. R.  07/2013)

"Thanks for turning out superb products, especially your Event Horizon focusers."  (S. S.)

"I am a retired Tool & Die Maker (28 yrs) and I am accustomed to making precision machines, etc.  The focuser which I bought from you is superb in all areas of fit and finish.  Keep up the great work!  (T. C.)

"Just received your Event Horizon Focuser - WOW - fit and finish were astronomical!!  Words can't describe how happy I am with your product.  I MEAN that!  Anyone who spends $$$ more on _______ is foolish.  THANK YOU all for a stellar product!  God Bless."  (K. C.)

"Product Report [on the EV-3r]:  Superb focuser fellas!  No doubt the best value in a refractor Crayford out there.  I'm so glad I didn't go for the import to save a paltry $30!  Solid, smooth, nice to look at, no slop.  Tech support with installation questions first rate.  Keep up the fine craftsmanship, ingenuity and value that JMI stands for."  (J. M.)

"I received my EV-3r focuser Saturday and am wholly impressed with it.  Thank you for the lovely engineering and attention to detail.  I'm absolutely convinced this focuser is the finest available, especially for the price - bar none!  (I've owned Moonlite, Feathertouch and GSO crayfords so I'm speaking from experience.)"  (J. M.)

"Based on the price, weight capacity and feedback from others, I decided to order the JMI..."  Online Cloudy Nights Telescope Reviews — JMI EV-1r Focuser  (Barry Etter)

"I got two great nights out with the scope and new [EV-2nM] focuser.  The difference is astounding.  It makes observing a real treat when you don't take so much time achieving a great, sharp view.  Also, it is nice to know the focuser feels the same no matter how low the temperatures get.  Thanks for your assistance."  (R. G.)

"The EV-2nM and enhanced extension tube are a fantastic upgrade from the stock focuser on my [telescope].  I had troubles getting the stock focuser to achieve a crisp focus because of image shift, backlash and vibration.  Those issues are all eliminated with this fine piece of equipment.  [I] only wish I had done the upgrade when I first got the telescope.  I'd have spent much more time observing and less frustration with trying to get the image focused.  [This is] a truly fine product and [your are] great people to deal with."

"My experience with your company has, to say the least, been outstanding.  I contacted you on Monday and spoke with helpful staff who conveyed a sense of both understanding my requirements and reaspsuring me that the item would arrive within the timeframe I needed.  A follow up call made to check progress was treated in the same friendly, knowledgeable way.  While I have not used the focuser outside yet (storms tonight), it mounted easily and took my accessories with ease.  I will be going to our clubs dark site this weekend and will put the unit through its paces.  Many thanks for upholding excellent customer care and providing the hobby with first class instruments.  Thanks.  (S. P.)

"[The EV focuser] is a thing of beauty!!  A wonderful addition to my SN 8".  Makes the scope look like a million bucks!  Thank you very much!  It has been a pleasure doing business with you!  And I plan to do business with you in the future.  A long time customer of JMI, Roger..."  (R. S.)

"I bought my EV-3n with a check, so I expected a delay but the focuser arrived well before I expected it.  The packing was great, the finish was beautiful, but there was a tiny "hitch" in the focuser movement that synched with the rotation of the knobs.  I called the office and was immediately put in touch with knowledgeable support (I work in support also - yours is top rate!) who gave me a suggestion to try and permitted me to undo the shaft box to inspect the shaft for more clues.  I found two tiny coincident gouges on either side of center, which had left two tiny scrims of metal on the shaft - not more than a few thousandths of an inch.  It may have been caused during shipping, although there wasn't any obvious damage to the box.  A little 1000 grit sandpaper on a flat stick and the problem is gone - I can't even tell where it was. Now the focuser works as well as it looks.  (T. F.)

"The EV-1n 2-inch motorized focuser I purchased from you was better than I had expected.  The ease of use was refreshing in these days of over complication.  I would certainly recommend this item to anyone considering the purchase of a motorized focuser."  (R. A. S.)

"I received my EV-2c focuser from you yesterday and immediately installed it on my C8 and took it outside for a test.  I must say that I am very pleased with its performance.  I think that this it the first time I have ever had my C8 in perfect focus.  Everything works to more than my expectations.  Thanks."  (R. G.)

"I got the focuser on Saturday and I have to tell you it is simply a work of art!  It installed easily and so far it seems to work great.  I have yet to get to try it out under dark skies but I am sure it is going to do the job.  One thing that impressed me was the absolute zero image shift while focusing.  I have never been able to get a real good collimation on this scope using my laser collimator.  As I rack the stock focuser in and out the laser dot moves quite a bit.  Not with the EV thought, it is rock steady.  The laser dot stays in one spot and doesn't move at all.  Great work!"  (D. C.)

"The quality of the workmanship on my new EV Focuser astonished me and was excellent.  It is so nice to get a piece of equipment made here and not in China."  (J. V. C.)

"I recently purchased a JMI EV [motorized focuser] for my [scope]...  The stock focuser is so sloppy and toy-like that precise focus really is not possible.  Hold the two in each of your hands (the EV and the stock focuser) and the difference is striking.  This is, hands down, the best upgrade I have made.  It makes a good scope great."  (R. G.)

"The EV-3n came in faster than I expected.  My first word when I opened the box was, WOW!  The quality and craftsmanship was far better than I expected.  Thank you JMI for building such quality gear for our telescopes.  I will be buying from you guys again."  (K. B.)

"I...note with pleasure that someone at last is manufacturing the Crayford Eyepiece Mount commercially.  I had no intentions of doing this myself...  I write to say, good luck in your venture and what better use could the new CEM be put than to grace your splendid range of well designed telescopes."  (J. Wall, Inventor of the C.E.M.)

Each focuser or accessory in the diagram above is labeled with its part number.  To see photos of each adapter, go to the Adapter Comparison Chart.

Generally, a medium SCT (Schmidt Cassegrain Telescope) is one with a 10" to 14" aperture.  A large SCT is one with a 16" or larger aperture (e.g. Meade LX200 16").  Although we refer to these accessories as SCT accessories, they will work on any Cassegrain telescope (e.g. Maksutov-Cassegrain) of the correct size with standard output threads.  Six of the mounting adapters (ADPT2SCT(L), ADPT3SCT(L), ADPT4SCT(L)) are for mounting the two NGF focusers (1.25" NGFMINC, 2" NGFC) specifically designed for Cassegrain telescopes.  Two of the mounting adapters (ADPT3XT, ADPT4XT) are for mounting the 3" EV-XTc focuser on a large SCT with mounting threads of 3" and 4" diameter respectively.

Most medium size SCTs come with an adapter that reduces the larger output threads to the smaller output threads found on the small SCTs.  These adapters usually cut into the light cone.  We designed the Large Format mounting Adapters (ADPT3SCT(L), ADPT4SCT(L)) to overcome this problem.  The larger version (ADPT4SCT(L)) is designed for the 4" threads on the Meade 16" LX200.  There are two more adapters (ADPT3XT, ADPT4XT) which are designed specifically for mounting the EV-XTc focuser.  All these adapters are non-vignetting.  In other words, they do not reduce the amount of light that gets to the eyepiece.

An "L" on the end of the part number indicates that a light shield is built in to the adapter.  The light shield portion of the adapter is shown in a light gray color in the chart above.  A light shield blocks any stray light coming through the bearing cavities and is normally not necessary unless you are using a CCD camera.  (The EV-XT design does not require any light shield.)

The threaded output adapter (ADPT2THREAD) duplicates the standard threads found on a small SCT.  The large threaded output adapter (ADPT3THREAD) duplicates the large threads found on the Meade LX200 16" telescope.  This allows you to use your standard SCT accessories on the back side of an EV/NGF focuser.  We have a standard 1.25" eyepiece adapter (ADPT2-1.25) to allow the use of 1.25" eyepieces in a 2" diameter drawtube.  The combination 1.25" eyepiece and T-thread adapter (ADPT2-1.25T) also works as a 1.25" eyepiece adapter but is designed for mounting cameras having a standard T-thread (including CCD cameras) into a 2" drawtube.

Future products for the EV-XTc may include special 1.25" eyepiece adapters to fit in the 2" eyepiece adapter (ADPT3-2).