18" Premium Ultra Light Dobsonian Telescope

f/4: $4,095

f/4.5: $3,595

Order Info
  • A quantum leap in optical performance - the UL 18 Truss Dobsonian telescope's huge 18" diameter primary mirror gathers over 5 times more light than popular 8" reflectors or more than twice the light grasp of a 12" telescope
  • A Premium, Light, Compact and Portable Design - About half the weight of traditional Dobsonian telescopes
  • Outstanding Images - Premium quality, diffraction limited Newtonian optical systems will deliver stunning views of the heavens from dark sky sites
  • Light, Strong, Compact and Extremely Portable - The Hubble UL18 features a precision-machined all-metal construction. Fully assembled the UL18 weighs at about 71 pounds. It has 8 rigid truss tubes and extremely strong and portable folding ALT bearing structure. It features a real mirror box for safe mirror protection, and convenient storage and transportation
  • Exclusive Optical Technology - The UL18 features Hubble lightweight sandwich mirror with an optimized thermal design that cools up to 10 times faster than the regular solid mirrors
  • Fast Optics - The UL18 fast optical system delivers bright images and features a short tube keeping the eyepiece conveniently close to the ground
  • Enhanced Coating - The state of the art Enhanced Coating on both the primary and the secondary mirrors.
  • Modular and Compact Design: The Hubble UL18 is delivered in several preassembled modules. The entire systems can be assembled easily and quickly, as little as a few minutes.


UL18 Specs

  • Optical design: Reflector
  • Optical diameter: 457.2mm
  • Focal length : ~1860mm (f/4) / ~2058mm (f/4.5)
  • Eyepiece height at zenith: ~1730mm, 68 in(f/4) or ~1930mm, 76 in (f/4.5)
  • Optics type: Parabolic
  • Eyepieces: Not included
  • Optical quality: Diffraction limited++ (Strehl 0.95+ for the primary mirror, 1/10 lambda or better in PV for the secondary mirror)
  • Finder scope: Not included
  • Focuser: 2" dual-speed linear bearing Crayford
  • Secondary mirror obstruction : 90 mm
  • Secondary mirror obstruction by diameter : 19.7% (f/4), 17.2% (f/4.5)
  • Secondary mirror obstruction by area : 3.9% (f/4), 3.0% (f/4.5)
  • Mirror coatings/over-coatings: 96% Enhanced coating on both of the primary and secondary mirrors
  • Tube material: 6063-T6 Aluminum Alloy tubes with black zinc plated steel knob screws; Aluminum Alloy main structure (OTA and mount) and structure steel mirror cell.
  • Length of optical tube: ~72 in (f/4), ~79 in (f/4.5)
  • Weight, optical tube: 62.0 lbs
  • Weight, fully assembled: 72.0 lbs.
  • Additional, optional accessories: 8x50 Finder, Shroud, Wheelbarrow, Vinyl foam Cushioned Grips
  • Other features: Sling lateral support and deluxe push-pull brass knob collimation screws

Options (add-ons)

Options are optional add-ons that can be specified EITHER on the paypal special instructions section during payment OR - after payment - in an e-mail to:

E-mail: info@hubble-optics.com

Payment Info
  • Light Weight Red Dot Finder Scope with Brackets and Dovetail: $45
    • Simple, effective, and easy to adjust 1 x Red Dot Finder scope. Free shipping when ordered with the system.

  • 8 x 50 Straight Through Illuminated Finder Scope with Brackets and Dovetail: $100
    • A top quality 50mm achromatic finder offering an inverted and reversed image, perfect for Newtonian Telescope. A deluxe quick release double-ring Finder Bracket including a dovetail base is included. There will be $15 additional charge for the surface delivery, or $25 additional charge the air delivery.
    • The scale markings and open center of the 8 X 50 Straight Through Finder allows you to measure distances and easily center an object in the field of view. The brightness of the reticle can be adjusted, which is nice when you are searching for fainter objects.
    • The illuminator screws into the end of the finder and can be removed easily to change batteries. The deep red illumination can be adjusted for brightness.

  • Truss Tube Grips: $7 each
    • 0.9m (35.5"), slid-on round cushioned grips, made of vinyl foam, they insulate, cushion vibration and protect the truss tubes. Free shipping when ordered with system.

  • Wheelbarrow: $120 +Shipping
    • The strong stainless steel handles, two top quality 6" pneumatic tires with ball bearing.  The shipping cost will be $100.

  • Shroud: $95 (f/4), $100 (f/4.5)
    • Made from the top quality Nylon/Lycra blended materials, it is one of the options you would really like to have. Free shipping when ordered with the system.

  • Truss Tube Carry Bag: $50 (f/4), $60 (f/4.5)
    • Made from the deluxe waterproof Nylon material with draw-string cord. Free shipping when ordered with the system.

  • 5-Star Artificial Star: $19.95 (free shipping if ordered with system)
    • It is really the time to have one, if you still don't have one yet!

  • Fan
    • Sorry, but It is not an option for UL18. You simply do not need one for our thin solid mirror!

  • Scope Storage Cover: $95 (f/4), $100 (f/4.5) (free shipping when ordered with the system)
    • Made with nice and strong polyurethane coated nylon fabric; light reflecting, water and dust resistant. A complete protection for your scope not only in the storage but also in the field. You don't need it if you store the scope in a luggage case or the custom made backpack.

  • Mirror Cover: $50 (free shipping when ordered with the system)
    • A very nice and strong plastic mirror cover

  • Light Baffle: $40
    • Free shipping when ordered with system

  • Hubble SkyHub Wireless Digital Setting Circle: $249 + $45 S&H
    • Breakthrough Wireless Digital Setting Circle with revolutionary high resolution, low power consumption ball bearing encoders at an inconceivable special price! Learn more here

  • Hubble SiTech GOTO: $1995
    • Simply the most powerful GOTO system at an extremely affordable price. Learn more here

Features of the UL18:

Exclusive Sandwich Mirror Technology:

Our sandwich mirror technology has been used to manufacture research-grade optical elements and proven by over a half dozen years of successful applications at research facilities such as NASA, California State Polytechnic University San Luis Obispo, for the US Army, and in amateur telescopes around the world. Hubble sandwich mirror’s open core and close back design not only allows air to circulate through the mirror, but also provide the maximum structure strength to allow a simpler mirror cell design. Our sandwich mirror will reach thermal equilibrium up to 10 times faster than a traditional solid mirror and means the mirror can deliver great views even as the air around the telescope is changing temperature.

Why is thermal equilibrium so critical? The main issue is "mirror seeing," the turbulence seen through the eyepiece of the telescope when the air above the mirror is different from the mirror itself. Since a sandwich mirror cools far more rapidly than a solid mirror of the same thickness, this major source of distortion is eliminated quickly, giving you sharp and stable views. With ever- changing temperatures during observing or imaging, your thick and solid mirror may never reach equilibrium, and never reach its full optical potential. This is one of the major reasons why our lightweight-sandwich mirror has superior optical performance in real world situations, even without an active cooling system. (Active cooling systems, such as fans, introduce their own problems, such as micro vibration, which may seriously degrade the image quality.) Our sandwich mirrors reach equilibrium extremely fast, and without any external disturbing aid.

Enhanced Optical Coatings:

The Hubble UL18 primary mirror and secondary mirror are both coated with the state of the art 96% Enhanced optical coatings to assure it collects as many (while scattering as little) photons as possible to focus it into a bright and contrast-rich image. The optimal 96% enhanced coating has multiple over-coating of precision controlled dielectric layer to maximize the reflectivity and provide excellent chemical and mechanical protection for the mirror coating.

A Real Mirror Cell In A Real Mirror Box:

The UL18 has an extensively modeled and optimized 18-point flotation system that provides more than adequate support for the sandwich mirror. The three-point Push-Pull collimation system is completely independent from the sling lateral support. It will totally eliminate the often-found potato chip astigmatism introduced by sling belt when using the simple 3 pivoted bolts collimation system. In a simple pivoted bolts collimation system, the collimation of the primary mirror may cause the sling belt to pull the mirror axially on the mirror edge, bending the mirror to a potato-chip shape, causing annoying astigmatism. It also comes with a real mirror box for easy and safe mirror protection and transportation.

All Metal Construction:

The UL18 mechanical structures have been extensively modeled via 3D CAD and advanced FEA to provide the optimal structure strength and stability. Machined with Computer Numerical Control (CNC) technology and hand fitted to assure proper fit and finish. Super strong T6063-T3 aluminum alloy truss tubes, structure steel mirror cell and aluminum alloy OTA and mount structure. Completed with deluxe and environmentally friendly black powder coating, it is such a pleasure to look at, not to mention the enjoyment to look through.

Dual-Speed 2-inch Linear Drive Crayford Focuser:

The Hubble UL18 comes with a precision dual-speed, 2-inch diameter focuser. It's a beautiful piece of precision machining that enhances the viewing experience as well as the overall impression of a premium quality instrument you'll have with this telescope. This focuser is robust! It is a zero-backlash "Crayford-style" design further enhanced with modern "linear bearings" meaning you get a rock-solid, super smooth focusing experience that can handle the weight of even the heaviest of modern eyepieces. Its tension, the pressure on the drawtube, is preset to a very reasonable level, but adjustable to lock heavy equipment in place if desired. The smaller stainless steel focus control adjusts focus at a rate 8 times finer than the larger focus wheels. This fine adjustment allows for critical focusing during high power visual observing or for imaging applications. The focuser has 50mm of travel distance.

If you've read enough, and want to just know how to buy it already, then click below!

Payment Info

Which UL18, f/4 or f/4.5?

Advantages of f/4.5:

  • Sharper images. It has about 40% less coma than UL18 f/4.0, no need for a coma corrector at all.
  • With the special introduction offer, you save $800 over UL f/4!
  • Smaller central obstruction, 3.1” (f/4.5) v.s. 3.5” (f/4.0) secondary mirror
  • Easier to achieve perfect collimation

Advantages of f/4:

  • No ladder is needed for most people; while you may need one-step ladder for an f/4.5 when close to zenith direction.
  • Wider FOV.

Both f/4 and f/4.5 will provide you the excellent views. The f/4.5 provides the perfect view for the most demanding observer, without coma corrector. A coma corrector is strongly recommended for the UL18 f/4.

With our unique two-section truss tubes for UL18 f/4.5 (one section truss for f/4), f/4.5 is just as portable and strong as f/4. At the end, it is really your personal preference.

Please note that some counter weight (real and/or a virtual spring counter weight) will be required for f/4.5 at the bottom, which is NOT provided.

Happy Customers

Bill Porte's, His-n-Her's UL18s in the Sierra Nevada Mountains

Rick's and Peg's, His-n-Her's UL18s at Okie-Tex Star Party

Dan Shiner's UL18 at Cherry Springs Star Party 2019

Instructions Manual

Click here for the instructions manual PDF - the Guide and Setup Process.


Click here for the UL18 dimensions when folded.


Prices: (f/4) is $4,095 - (f/4.5) is $3,595

$2,047.50 (f4) or $1,797.50 (f/4.5) deposit at the order time, rest, including options and shipping will be paid before the delivery (about 60 days after the deposit) via a Paypal invoice.

Please note that the 60 days delivery is the estimated production lead time only which does not include shipping transit time.

Please specify your requested options in your payment for the deposit.

Choose your f /#

Shipping and Handling

We offer very reasonable worldwide shipping costs (at least for most of the countries) for the total system. Please understand the surface shipping is a great value, but may take more than additional 10 weeks for the delivery.

UL18 will be shipped in 4 boxes: the main structure 1 & 2, the truss tubes and the primary mirror.

Country Economy(US$) Regular(US$)
US NA 870
US(Hawaii) NA 920
Austria NA 720
Australia NA 1017(EMS)
Belgium NA 770
Brazil NA 2350(*)
Canada NA 826
Chile NA 992
Denmark NA 765
France NA 790
Germany NA 780
Israel NA 860
Italy NA 710
Japan NA 510
Korea, South NA 510
Lithuania NA 1660
Korea, South NA 510
Mexico NA 905
Netherlands NA 710
New Zealand NA 830
Norway NA 800
Philippines NA 415
Poland Na 785
Portugal NA 905
Romania NA 880
Russia NA 1220
Singapore NA 425
South Africa NA 1005
Spain NA 830
Sweden NA 780
Switzerland NA 775
Taiwan NA 480
UK NA 800

* Shipped via Fedex, the exact cost depends on your specific address.

For EU customers, please contact Astroshop EU for their wonderful services:

For Japanese customers, please contact Kokusai Kohki and Astro Street for their wonderful services:

To see our listings of already stocked (miscellaneous) items, please visit our E-bay, by clicking here