{"product_id":"hubble-optics-18-premium-ultra-lightweight-dobsonian","title":"Hubble Optics 18\" Premium Ultra Lightweight Dobsonian","description":"\u003cdiv data-mce-fragment=\"1\"\u003e\n\u003cul class=\"overview-text\"\u003e\n\u003cli\u003eA 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\u003c\/li\u003e\n\u003cli\u003eLight, 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\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 class=\"header\" data-mce-fragment=\"1\"\u003eUL18 Specs\u003c\/h3\u003e\n\u003cul class=\"ul-with-padding\" data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003eOptical design: Reflector\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eOptical diameter: 457.2mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eFocal length : ~1860mm (f\/4) \/ ~2058mm (f\/4.5)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eEyepiece height at zenith: ~1730mm, 68 in(f\/4) or ~1930mm, 76 in (f\/4.5)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eOptics type: Parabolic\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eEyepieces: Not included\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eOptical quality: Diffraction limited++ (Strehl 0.95+ for the primary mirror, 1\/10 lambda or better in PV for the secondary mirror)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eFinder scope: Not included\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eFocuser: 2\" dual-speed linear bearing Crayford\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSecondary mirror obstruction : 90 mm\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSecondary mirror obstruction by diameter : 19.7% (f\/4), 17.2% (f\/4.5)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSecondary mirror obstruction by area : 3.9% (f\/4), 3.0% (f\/4.5)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eMirror coatings\/over-coatings: 96% Enhanced coating on both of the primary and secondary mirrors\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eTube 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.\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eLength of optical tube: ~72 in (f\/4), ~79 in (f\/4.5)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eWeight, optical tube: 62.0 lbs\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eWeight, fully assembled: 72.0 lbs.\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eAdditional, optional accessories: 8x50 Finder, Shroud, Wheelbarrow, Vinyl foam Cushioned Grips\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eOther features: Sling lateral support and deluxe push-pull brass knob collimation screws\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"text-block-container-grey\" data-mce-fragment=\"1\"\u003e\n\u003chr data-mce-fragment=\"1\"\u003e\n\u003ch3 class=\"header\" data-mce-fragment=\"1\"\u003eFeatures of the UL18:\u003c\/h3\u003e\n\u003cp class=\"feature-title\" data-mce-fragment=\"1\"\u003eExclusive Sandwich Mirror Technology:\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eOur 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.\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eWhy 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.\u003c\/p\u003e\n\u003cp class=\"feature-title\" data-mce-fragment=\"1\"\u003eEnhanced Optical Coatings:\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eThe 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.\u003c\/p\u003e\n\u003cp class=\"feature-title\" data-mce-fragment=\"1\"\u003eA Real Mirror Cell In A Real Mirror Box:\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eThe 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.\u003c\/p\u003e\n\u003cp class=\"feature-title\" data-mce-fragment=\"1\"\u003eAll Metal Construction:\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eThe 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.\u003c\/p\u003e\n\u003cp class=\"feature-title\" data-mce-fragment=\"1\"\u003eDual-Speed 2-inch Linear Drive Crayford Focuser:\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eThe 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.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv data-mce-fragment=\"1\"\u003e\n\u003chr data-mce-fragment=\"1\"\u003e\n\u003ch3 class=\"header\" data-mce-fragment=\"1\"\u003eShould I choose the f\/5 or f\/4.5?\u003c\/h3\u003e\n\u003cp class=\"feature-title\" data-mce-fragment=\"1\"\u003eAdvantages of f\/5:\u003c\/p\u003e\n\u003cul class=\"ul-with-padding\" data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSharper images. It has about 40% less coma than UL18 f\/4.0, no need for a coma corrector at all.\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eWith the special introduction offer, you save $800 over UL f\/4!\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSmaller central obstruction, 3.1” (f\/4.5) v.s. 3.5” (f\/4.0) secondary mirror\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eEasier to achieve perfect collimation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"feature-title\" data-mce-fragment=\"1\"\u003eAdvantages of f\/4.5:\u003c\/p\u003e\n\u003cul class=\"ul-with-padding\" data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003eNo ladder is needed for most people; while you may need one-step ladder for an f\/5 when close to zenith direction.\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eWider FOV.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-mce-fragment=\"1\"\u003eBoth f\/5 and f\/4.5 will provide you the excellent views. The f\/5 provides the perfect view for the most demanding observer, without coma corrector. The f\/4.5 also provides a wonderful and wider view without coma corrector (some people may notice small amount of coma at the edge of a wide angle Eyepieces, but most people will not be bothered or even notice this).\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eWith our unique two-section truss tubes for f\/5 (one section truss for f\/4.5), f\/5 is just as portable and strong as f\/4.5. At the end, it is really your personal preference. Please note that some counter weight will be required for f\/5 at the bottom, which is NOT provided.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv data-mce-fragment=\"1\"\u003e\n\u003chr data-mce-fragment=\"1\"\u003e\n\u003ch3 class=\"header\" data-mce-fragment=\"1\"\u003eHappy Customers\u003c\/h3\u003e\n\u003ca href=\"https:\/\/hubble-optics.com\/UL18.html#happy_1\" data-mce-fragment=\"1\" data-mce-href=\"https:\/\/hubble-optics.com\/UL18.html#happy_1\"\u003e\u003cimg class=\"img-responsive thumbnail\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/files\/BillP.jpg?v=1765050755\" data-mce-fragment=\"1\" data-mce-src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/files\/BillP.jpg?v=1765050755\"\u003e\u003c\/a\u003e\n\u003cdiv class=\"caption\" data-mce-fragment=\"1\"\u003e\n\u003cp data-mce-fragment=\"1\"\u003eBill Porte's, His-n-Her's UL18s in the Sierra Nevada Mountains\u003c\/p\u003e\n\u003ca href=\"https:\/\/hubble-optics.com\/UL18.html#happy_2\" data-mce-fragment=\"1\" data-mce-href=\"https:\/\/hubble-optics.com\/UL18.html#happy_2\"\u003e\u003cimg class=\"img-responsive thumbnail\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/files\/RickandPegNew.jpg?v=1765050759\" data-mce-fragment=\"1\" data-mce-src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/files\/RickandPegNew.jpg?v=1765050759\"\u003e\u003c\/a\u003e\n\u003cp data-mce-fragment=\"1\"\u003eRick's and Peg's, His-n-Her's UL18s at Okie-Tex Star Party\u003c\/p\u003e\n\u003ca href=\"https:\/\/hubble-optics.com\/UL18.html#happy_3\" data-mce-fragment=\"1\" data-mce-href=\"https:\/\/hubble-optics.com\/UL18.html#happy_3\"\u003e\u003cimg class=\"img-responsive thumbnail\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/files\/UL18-1-Dan.jpg?v=1765050762\" data-mce-fragment=\"1\" data-mce-src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/files\/UL18-1-Dan.jpg?v=1765050762\"\u003e\u003c\/a\u003e\n\u003cp data-mce-fragment=\"1\"\u003eDan Shiner's UL18 at Cherry Springs Star Party 2019\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Hubble Optics","offers":[{"title":"f\/4","offer_id":44336024060123,"sku":"UL18 f\/4","price":6841.0,"currency_code":"CAD","in_stock":true},{"title":"f\/4.5","offer_id":44336024125659,"sku":"UL18 f\/4.5","price":6146.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/files\/hubble-optics-telescope-hubble-optics-18-premium-ultra-lightweight-dobsonian-40094931517659.jpg?v=1697556195","url":"https:\/\/telescopescanada.ca\/products\/hubble-optics-18-premium-ultra-lightweight-dobsonian","provider":"Telescopes Canada","version":"1.0","type":"link"}