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NGT-18 Product Information

NGT-18 Optional Upgrades

NGT-18 Optional Accessories

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18" NGT Telescope

18" Split-Ring Newtonian with GOTO


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NGT-18 Product Information  DISCONTINUED


• Open truss Newtonian
• Split-ring equatorial mount
• Rotating nose assembly
• Compact size
• Fast assembly
• 18-point flotation mirror cell
• Includes StellarCAT ServoCAT Jr. Track/GOTO
compatible with Go-To computers and planetarium software
NGC-superMAX (Argo Navis™) Go-To computer
• CCD Autoguider compatible
• Battery and AC operation
• Adjustable focal point
• Snap-fit Serrurier truss rods
• Massive 2" declination ball bearings
• Personalized name plaque
• JMI's celebrated quality construction


Type:  Newtonian reflector
Mount:  Equatorial split-ring
Mirror:  18" f/4.2 or f/4.5 enhanced primary, 4" enhanced diagonal secondary
Power:  12vDC internal lead-acid batteries or AC adapter for fan operation
            12vDC external battery power source (included) for ServoCAT and drive operation
Weight:  approximately 245 lb., the heaviest single component is 75 lb.
Height:  80" assembled, 30" collapsed, Eyepiece height 76" at Zenith
Width:  36"
Depth:  30"
Finder:  9x50 straight through

Standard Equipment

Rotating Nose Assembly for comfortable viewing of any part of the sky.
EV-2n Focuser with Motor for motorized focusing.  (upgrades available)
Extension Tube for 2" Focuser.
25mm 1.25" Plössl Eyepiece.
9x50 Finder Scope
(straight-through) with dovetail mount.
Piggy-Back Camera Mount for piggy-back photography.
Off-Axis Counterweight for attaching to the piggy-back camera mount (2).
Serrurier Truss Rods snap fit into heat treated, spring steel cavities.
Adjustable Focal Point including three different nose assembly mounting positions for visual and photographic work.
Sliding Counterweights positioned along the truss rods for fine tuning the balance (4).
Split-Ring Equatorial Drive with 36" drive ring.
18-Point Flotation Mirror Cell.
18" Mirror.
  92% reflectivity.  (upgrade available)
Primary Mirror Dust Cover with Two F-Stops providing 3" and 6" apertures.
Mirror Cooling Fan with filter and grill.
Integrated Optical Encoders and a StellarCAT tracking, slewing and Go-To system.
NGC-superMAX (Argo Navis) Computer digital setting circles with an over 29,000-object database and too many features to list here.
Battery or AC Power with 12vDC 4.6A rechargeable lead-acid batteries, audible low battery alarm, 12vDC cigarette lighter adapter and 110vAC/60Hz or 220vAC/50Hz (specify) wall transformer.
External Battery Pack rated at 12vDC, 17 Amp Hours.
Built-In Lifting Handles permit easy transportation.
Latitude Adjustment with scale for fine adjustment of latitude setting.  Adjusts from 30º to 55º.  (modification available—see Low Latitude Base Wedge below)

* Telescope prices are for the standard telescope configuration.  Upgrades and Options are at additional cost.  The listed price also does not include the crating charge ($275) and any shipping and handling charges.  Please call for a shipping quote.  A 10% DEPOSIT is required with all telescope orders (5% IS NON-REFUNDABLE).  Telescopes are custom-built based on the options selected by the customer and therefore require time to build.  The remaining amount due must be paid before the telescope is shipped.

18" NGT Optional Upgrades

Galaxy Optics Mirror Upgrade
With Interferogram


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Upgrade to Galaxy Optics Mirrors

This option upgrades to a Galaxy Optics precision annealed 2" thick Pyrex diffraction-limited f/4.2 primary mirror with enhanced coating giving 96% reflectivity and a matching Galaxy Optics precision annealed Pyrex secondary mirror with 98% reflectivity.  An Interferogram is included.  (With Galaxy primary mirrors, two additional options are available: "Premium" mirror selection based on Interferometric data and C2 enhanced coatings with 98% reflectivity.  Call for more information including pricing.)

NOTE:  This is an upgrade from our standard primary mirror to a Galaxy mirror, at the time of purchase only.  This option cannot be purchased separately.


EV-1nM Focuser Upgrade
Add Dual Speed Knobs and a Dial Indicator


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EV-1n Focuser with Motor

This option upgrades the focuser from the EV-2 model (EV-2nM) to the EV-1 model (EV-1nM).  The EV-1 includes Dual Speed Knobs and a Dial Positioning Indicator.


18" NGT Optional Accessories

Light Baffle
Nose Extension


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Light Baffle nose extension

Prevents stray light from entering into the focuser.


Telrad Finder


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Telrad Finder


Telrad Finder Mounting Adapter


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Telrad Finder Mounting Adapter


Extra Sliding Truss-Rod Counterweight


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Extra Sliding Truss-Rod Counterweight (each)


Truss-Rod Light Shroud
Light-Weight Black Fabric

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Truss Rod Light Shroud

Blocks stray light and air currents and helps keep dust off of the mirrors.  Made of light-weight black fabric with elastic at both ends.


Replacement Batteries
Two 6 volt, 4.5 amp-hr
Rechargeable Batteries


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One 12 volt, 7 amp-hr
Rechargeable Battery


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Replacement Batteries

The NGT-18 has two sets of batteries, internal and external.  The internal batteries can be used to operate the whole system for a short time.  However, they typically are used only to power the fan.  The external batteries are used to run the computers and drive system.

Replacement Maintenance-free Rechargeable Batteries
INTERNAL Battery Pack:  Two 6 volt, 4.5 amp-hr batteries in series (12v 4.5ah system)
EXTERNAL Battery Pack:  One 12 volt, 7 amp-hr battery (12v 7ah system)

For an optional three-battery external power pack, see our 21 Ah Power PAC battery pack.


Low-Latitude Base Wedge
for a Latitude Range of 15º to 30º


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Low Latitude Base Wedge for a latitude range of 15º to 30º


Permanent Observatory Mounting Hardware


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Permanent Observatory Mounting Hardware with Azimuth fine adjustment

The observatory mounting hardware allows fine adjustment for final positioning.


Azimuth Polar Alignment Base
for easier azimuth adjustments


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Azimuth Polar Alignment Base

For easier azimuth adjustments.


Handlebar and Wheels
Wheelbarrow-style Transportation


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Handlebar and Wheels

For easily moving the fully assembled telescope over most surfaces.  Uses 8" solid rubber ball bearing wheels.

The NGT-18's Handlebar and Wheels allow easy transportation with the nose assembly safely cradled inside the mirror tub assembly.


The new NGT-18 with GOTO (f/4.2)
The new NGT-18 with GOTO (f/4.5)
This and the following pictures are of the original NGT-18.  The new 18 is a GOTO scope using the StellarCAT ServoCAT system with the NGC-superMAX (Argo Navis) computer.  There are some slight differences in the drive ring area.
The NGT-18 packed comfortably in a mini-van with room for a C8 case.
The NGT-18 fits easily into any sub-compact station wagon.
The NGT-18 mirror dust cover includes 3" and 6" f-stops.
The NGT-18 includes an 18-point flotation mirror cell as standard equipment.
The NGT-18 has a very low profile and aesthetic appearance.

What is a Next Generation Telescope?

The Next Generation Telescope (NGT) is a uniquely designed equatorial Newtonian.  It features a low profile, split-ring equatorial drive, open Serrurier truss rod design, rotating nose assembly, compact size, JMI's celebrated quality construction and now a Go-To computer (NGT-18 Model).  The NGT is a revolutionary instrument that has won awards and acclaim throughout the world.  It is available in 12.5" (f/4.5) and 18" (f/4.2 or f/4.5) apertures.

Customer Comments

"The NGT is an equatorial mount with no field rotation, plus it is compatible with digital setting circles.  Also, there is no PEC to deal with as the RA drive is direct friction to the ring.  The all aluminum and stainless construction means little maintenance.  The low center of gravity gives it nice stability.  The best thing is the rotating nose assemble.  It makes collimation more difficult, but is so worth it."  (G. K.)

"(12/31/09)  I just wanted to let you know that I have been enjoying my NGT-18 for ten years now; I guess I finally found a cure for aperture fever.  Quite aside from providing many years of superb service, this great telescope has been the featured mainstay of my three published books from Springer (Visual Astronomy in the Suburbs, 2003; Visual Astronomy under Dark Skies, 2005, and the upcoming Make Time for the Stars, 2009), in which it has done valiant service in providing most of the illustrations, as well as being at the core of the approaches I advocate.  For some of my viewing, I will admit to combining two Collins I3 image intensifiers (with a binocular viewer), or even just one at a time (!), and have been simply astounded with what is attainable in real time.  The new Generation IV version is spectacular!!  It is possible to take sensational deep space virtual snapshots – even galaxies like M51 or NGC 891 – that look like lengthy time exposures!

However, the main purpose of all of this is simply to let you know how extremely happy I remain with my NGT-18.  There can't be a more ideal or satisfying telescope to use, and even more particularly, one that is more comfortable and relaxing.  The ready portability makes it possible to dismantle it, move it 100 miles to a dark sky site, reassemble it, yet find the collimation still at 100%!  The quality, performance and practicality remain beyond reproach, and even with the now relatively antiquated digital circles from the '90's, I still have yet to exhaust the potential, or feel the slightest need for 'go-to' capability, because the telescope is so easy to manage and use.  And accuracy of locating objects is more than adequate for any purpose.  I note that go-to capability is now offered with this model, but the need is surely more as a luxury rather than fulfilling any real necessity!

I have a new book in the works right now that will probably take up to 2 years to write.  Once again, my trusty NGT-18 will be the workhorse for everything in the book.  I know you would like to sell more telescopes, but what I have will probably take care of my needs for life!  It seems indestructible, completely reliable, utterly predictable and straightforward to use.   By all means use any of my words as testimonials in your catalog or elsewhere.

Wishing you all success in 2009!"  (Antony Cooke)

"It is a pleasure to do business with a company that supports their products after the sale.  ...My experience with you and your company allows me to recommend your products and service, without hesitation, to my friends and fellow amateurs."  (M. H.)

"It is one of the great joys of my life to have this superlative instrument."  (A. C.)

Frequently Asked Questions (FAQ)

Q. How long does it take to set up an NGT-18?
A. Using two people, the NGT-18 can be set up in about 10 minutes.
Q. Does the rotating nose assembly make collimation difficult or impossible?
A. Contrary to erroneous reports on the Internet—No.  Here are some comments from Tom Johnston who builds the NGT-12.5 and NGT-18 telescopes:

"Not only do I build the NGT-12.5 here at JMI but I also own one.  I use it primarily to monitor faint periodic comets (using an ST7) for the IAU.

"There is a very simple pro and con relationship with the rotating nose on the NGT.  This ability to place the eyepiece at a variety of comfortable positions in an enormous factor.  The ease of use really cannot be realized until you've spent a night observing with it.  In addition, the rotating nose allows you to place a heavy CCD camera in a more balanced and less stress producing position above the tube instead of hanging off the side.  I personally would not give up my rotating nose.

"Here is the flip side.  It is difficult to collimate IF you have never done it before because it requires that you find the best possible collimation position relative to the entire rotation of the nose.  After you've done it a few times, it's easy.

"Before the scope leaves JMI, a laser spot must stay within the small white circle placed at the center of the primary mirror, throughout the 360 degrees of rotation of the nose.  The spot may dance around a little bit inside the circle but it remains INSIDE.  Using a Cheshire eyepiece, we then adjust the primary slightly until it is as close as it can get for the entire rotation.  There may be a few places in the circle where the Cheshire indicator is not perfect...but it will be off only slightly.  It's something you do not easily see visually or in a CCD image...but people like to talk about it anyway.  The only problems I have heard of are when people try to collimate it like a normal (non-rotating) Newtonian."

Q. Does the NGT hold collimation?
A. We have found that this telescope stays in collimation much longer than the average Newtonian.  Most Newtonian reflectors need to be collimated every other time they are used.  A recent floor model NGT-12.5 remained collimated over a span of at least 15 sessions.   These sessions included two trips to major star parties (RTMC and Okie-Tex) and periodic comet observations and imaging in the mountains of both Colorado and Arizona.
Q. How do you polar align the telescope?
A. There is a latitude adjustment screw that runs down the center of the telescope base.   The screw is parallel to the polar axis and can be visually pointed at the celestial pole.  This process can get you to within one-half degree of polar alignment in only seconds and, of course, you can use the good old stardrift method (see Document no. 8 in our Document Library).
Q. Can the NGT be leveled?
A. All NGT equatorials have leveling screws and a bubble level located on the base.
Q. How does dew affect the telescope?
A. All components of this telescope are rust proof.  Water on the drive ring has no affect on the tracking.
Q. How accurate is the split-ring drive?
A. Split-ring drives have little or no periodic error.  In a random test of a polar aligned NGT-12.5, it held the Dumbbell Nebula in a 30 arc minute field of view for over an hour.  Autoguiding feedback data from an SBIG ST7 CCD camera has confirmed this precision.
Q. How does the wind affect the NGT?
A. All truss tube Newtonian telescopes that use a shroud are subject to windy conditions.  Sudden wind gusts are more of a problem than sustained winds when imaging with a CCD camera.  However, we believe that this telescope is not affected by wind any more than a standard German Equatorial Newtonian telescope.  Tom Johnston, Production Manager and NGT-12.5 and NGT-18 assembler, routinely uses production scopes (as part of JMI's Quality Control process) for gathering CCD images of periodic comets.  He reports very good results in moderate wind.
Q. Can the telescope be controlled by an autoguider?
A. With the proper cables and relay box (if needed) any autoguider can control an NGT-12.5 or NGT-18 telescope.