{"product_id":"used-18-obsession-ultracompact-dobsonian-w-nexus-dsc-and-servocat","title":"Used Loaded 18\" Obsession UltraCompact Dobsonian w\/Nexus DSC and ServoCAT","description":"\u003cp class=\"larger_text\"\u003e\u003cstrong\u003eCondition\u003c\/strong\u003e: This is a used 18\" Obsession Dobsonian from about 2015 in very good condition.  You've heard of the quality that is an Obsession scope, now come see it for yourself. \u003c\/p\u003e\n\u003cp class=\"larger_text\"\u003eThe mirror is in good shape, but it is definitely dusty.  See the photos, where we've tried to capture this - the dust you see in different areas is consistent across basically the entire surface of the mirror.  In addition to the general dust, there are a couple of small spots on the edge of the mirror surface.  One of these spots is where masking tape contacted the mirror.  You may be able to clean this off yourself with GooGone, or its optical equivalent.  (We have no idea if GooGone will work or will be worse for the optics.)  \u003cem\u003eYou will definitely want to give the mirror a good and thorough cleaning after purchase.\u003c\/em\u003e  \u003c\/p\u003e\n\u003cp class=\"larger_text\"\u003eThe scope is in mechanically excellent condition - everything works. It includes a Feathertouch Focuser.  This scope includes both the Nexus and Argo Navis digital setting circles as well as the ServoCAT goto drive\/tracking system. We've tested the Nexus DSC system and the encoders are working.  We've tested the ServoCAT system and the motors work in all four directions. \u003c\/p\u003e\n\u003cp class=\"larger_text\"\u003eIt also includes a shroud for the tube, as well as light shields for the primary mirror at the bottom of the tube, and for the secondary mirror at the top of the tube.  \u003c\/p\u003e\n\u003cp class=\"larger_text\"\u003eYou will need to make sure that you can handle a scope of this size and complexity:  it is over 6 feet tall, and you will need to work with the plugs and the cabling to make sure everything is functioning as it should.  While we can't really assist you with this, as we don't know how everything works together, the previous owner has volunteered to give you some advice about disassembling and reassembling.  We do have both the original manuals and the previous owner's cheat sheets to assist you in this regard.  \u003c\/p\u003e\n\u003cp class=\"larger_text\"\u003e\u003cmeta charset=\"utf-8\"\u003eHere's everything that's included - and it is loaded: \u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"larger_text\"\u003eObsession 18” f4.2 UC (Ultra compact) OMI Primary and Astrosystems secondary\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eServoCat GOTO drive upgraded with Nexus DSC Pro (digital setting circles), powered ground board system installed and with ServoCat Hand controller. Scope is set up for three means of control:\n\u003cul\u003e\n\u003cli class=\"larger_text\"\u003e(1) using SkySafari as the Planetarium software for control and GOTO;\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003e(2) scope can also be used as PUSH\/TO or\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003e(3) controlled by ServoCat Hand controller \u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eFeathertouch focuser with curved rotatable base, compression rings and feather touch 1.25” to 2.0” eyepiece adapter\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eMarkless Astronomy digital setting circle (DSC) mounting stalk\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eNexus DSC (digital setting circles)\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003ePegasus Astro Pocket Powerbox Advance Gen2\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eArgo Navis DSC\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eDew heater for secondary\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eTelrad finder\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eAstromania Cheshire collimator (long version)\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eAstrosystems Laser Colllimator with Barlow attachment\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eApertura universal 10 Amp AC Adapter\/power supply\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003ePyramid PS-9KK Regulated 12 volt Power supply\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003e12 volt cooling fan for primary\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eSide bearing stabilizer bars\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003e10K encoders and encoder arm assembly\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eRobinson Jig\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eCounterweight kit\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eRipstop Nylon Light shroud (with 2 fiber glass support sticks)\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eUpper and lower light baffles\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eAstrosystems Telescope cover for 18UC scope\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eAstrosystems Truss Tube carry case\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eWheel barrow handles for scope with 10 inch pneumatic wheels\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eWhite travel\/storage case for 18UC scope\u003c\/li\u003e\n\u003cli class=\"larger_text\"\u003eQuick start Instructions and manual.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlso included is an old Mallincam system.  \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eNO WARRANTY, GUARANTEE, OR RETURNS ON THIS ITEM. BUYER TO INSPECT PRIOR TO PURCHASE.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThis is only available for in-store pickup.  \u003c\/strong\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003cp class=\"larger_text\"\u003e \u003c\/p\u003e\n\u003cp class=\"larger_text\"\u003eJust your size. Large Aperture, no big ladder needed! Our most popular model.\u003c\/p\u003e\n\u003cp\u003eThe Obsession 18\" is the ultimate compact scope for the discriminating enthusiast who wants big aperture in a small package.\u003c\/p\u003e\n\u003cp\u003eThere are no short cuts in construction or performance.\u003c\/p\u003e\n\u003cp\u003eThe Obsession 18\" features the same quality craftsmanship and award winning design as found on our renown 20, 25, 30 and 36 inch telescopes.\u003c\/p\u003e\n\u003cp\u003eA small step ladder is required when the scope is pointed near the zenith but most observing will be done with your feet on the ground.\u003c\/p\u003e\n\u003cp\u003eWe've done our homework - the 18\" is easy to set up and a joy to use.\u003c\/p\u003e\n\u003cp\u003eFantastic deep sky and planetary images.\u003c\/p\u003e\n\u003cp\u003eOne look and you'll re-learn what it means to be excited about astronomy.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003ctable width=\"470\" border=\"0\" cellspacing=\"2\" cellpadding=\"0\" class=\"comparison_table\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth scope=\"col\"\u003e5 times the light gathering power of an 8 inch Schmidt-Cassegrain\u003c\/th\u003e\n\u003cth scope=\"col\"\u003eObsession\u003cbr\u003e18\"\u003c\/th\u003e\n\u003cth scope=\"col\"\u003eTypical\u003cbr\u003e8\"\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eLimiting stellar magnitude:\u003c\/th\u003e\n\u003ctd\u003e16\u003c\/td\u003e\n\u003ctd\u003e14.0\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eRayleigh Resolution Limit:\u003c\/th\u003e\n\u003ctd\u003e0.31\u003cbr\u003earc seconds\u003c\/td\u003e\n\u003ctd\u003e0.68\u003cbr\u003earc seconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eContrast limit:\u003cbr\u003e(minimum diameter before a\u003cbr\u003enebular object fades from view)\u003c\/th\u003e\n\u003ctd\u003e4.8\u003cbr\u003earc minutes\u003c\/td\u003e\n\u003ctd\u003e11.0\u003cbr\u003earc minutes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cdiv class=\"two_col_left_col\"\u003e\n\u003ch2\u003e\u003cbr\u003e\u003c\/h2\u003e\n\u003cdiv class=\"two_col_left_col\"\u003e\n\u003ch2\u003e18\" Specifications:\u003c\/h2\u003e\n\u003cp\u003e\u003cem\u003eMetric info shown in italics\u003c\/em\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003ePrimary Mirror:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e18\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e457 mm\u003c\/em\u003e\u003cspan\u003e \u003c\/span\u003eOstahowski, or OMI 2 inch thick mirror\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/optics\/index.php#fused_quartz\"\u003eFused silica glass\u003c\/a\u003e\u003cspan\u003e \u003c\/span\u003estandard on all 18\" Classic primary mirrors.\u003c\/li\u003e\n\u003cli\u003e96% reflectivity\u003c\/li\u003e\n\u003cli\u003eEnhanced Aluminum Coating and Dielectric Overcoat (a supreme coating)\u003c\/li\u003e\n\u003cli\u003eCenter marked for precise collimation\u003c\/li\u003e\n\u003cli\u003eplus Interferometry certification\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003esee\u003cspan\u003e \u003c\/span\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/optics\/index.php\"\u003eOptics page\u003c\/a\u003e\u003cspan\u003e \u003c\/span\u003efor more info\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eSecondary Mirror:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003ePre-installed\u003c\/li\u003e\n\u003cli\u003e3.1\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e79 mm\u003c\/em\u003e\u003cspan\u003e \u003c\/span\u003eUnited Lens 1\/10 wave or better\u003c\/li\u003e\n\u003cli\u003eInterferogram included\u003c\/li\u003e\n\u003cli\u003e96% reflectivity at 550 nm\u003c\/li\u003e\n\u003cli\u003eSuper enhanced Brilliant-Diamond non-fading multi-dielectric coating\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003esee\u003cspan\u003e \u003c\/span\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/optics\/index.php\"\u003eOptics page\u003c\/a\u003e\u003cspan\u003e \u003c\/span\u003efor more info\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eFocal Length:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e75\" (± 2\") -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e1900 mm (± 50 mm)\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"two_col_right_col\"\u003e\n\u003cbr\u003e\n\u003ch3\u003eEyepiece Height at Zenith:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e(approximately) 71\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e180 cm\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eMirror Cell:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e18-point\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eTruss Pole:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLength: 49\" (± 2\") -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e140 cm (± 5 cm)\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eDiameter: 1.25\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e32 mm\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eWall Thickness: 0.035\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e0.9 mm\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eUpper Assembly:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eDiameter: 22\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e56 cm\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eHeight: 12\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e30 cm\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eWeight: 9 lbs. -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e4.1 kg\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eLower Assembly:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eA= 26\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e66 cm\u003c\/em\u003e\u003cspan\u003e \u003c\/span\u003e| B= 27\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e68 cm\u003c\/em\u003e\u003cspan\u003e \u003c\/span\u003e| C= 21\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e53 cm\u003c\/em\u003e\u003cspan\u003e \u003c\/span\u003e| D= 25\" -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e63 cm\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/telescopes\/dimensions.png\" rel=\"lytebox\"\u003esee diagram\u003c\/a\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eMirror Box weight:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eThe heaviest component (what you don't lift): 80 lbs -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e36 kg\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eWeight at Handles: (what you lift at Wheelbarrow handles): 18 lbs -\u003cspan\u003e \u003c\/span\u003e\u003cem\u003e8 kg\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"two_col_right_col\"\u003e\n\u003ch2\u003eStandard Features and Accessories:\u003c\/h2\u003e\n\u003ch3\u003eWheelbarrow handles\u003c\/h3\u003e\n\u003cp\u003eComes standard on all Obsessions 12.5\" through 25\" at no extra charge.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003ePrimary Mirror Coating\u003c\/h3\u003e\n\u003cp class=\"justify\"\u003eEnhanced Aluminum - 96% reflectivity, with dielectric overcoat (a supreme coating) standard on all primary mirrors. See\u003cspan\u003e \u003c\/span\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/optics\/index.php\"\u003eOptics page\u003c\/a\u003e\u003cspan\u003e \u003c\/span\u003efor more info.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eSecondary Mirror Coating\u003c\/h3\u003e\n\u003cp class=\"justify\"\u003eAn Obsession exclusive - Super enhanced Brilliant-Diamond is standard on all Obsession secondary mirrors. This premium multi-dielectric coating has 96% reflectivity at 550 nm. The ultimate coating for the deep sky obsessed. This coating is standard on all Obsession secondaries at no extra charge. Brilliant-Diamond is just one of the reasons Obsessions out perform all others.\u003c\/p\u003e\n\u003cp class=\"justify\"\u003eWith 96% enhanced on the primary and our standard 96% Brilliant Diamond secondary, the optical system is equivalent to an extra 2\" of aperture!\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e12 volt cooling fan\u003c\/h3\u003e\n\u003cp\u003e\u003cem\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/accessories\/index_images\/12-V-cooling-fan-rh-2871.jpg\" rel=\"lytebox\"\u003e\u003cimg src=\"https:\/\/www.obsessiontelescopes.com\/accessories\/index_images\/12-V-cooling-fan-rh-2871-200px-L.jpg\" alt=\"telescope mirror cooling fan\" width=\"200\" height=\"133\" class=\"img_border\"\u003e\u003c\/a\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/em\u003e\u003c\/p\u003e\n\u003cp\u003e12 volt cooling fan comes standard on all Classic and Ultra Compact scopes.\u003c\/p\u003e\n\u003cdiv class=\"clear\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003chr\u003e\n\u003ch3\u003eFused quartz\u003c\/h3\u003e\n\u003cp\u003e18” Obsessions use fused quartz for the primary mirror glass.\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/optics\/index.php#fused_quartz\"\u003emore info\u003c\/a\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003cp\u003e\u003cspan style=\"font-family: -apple-system, BlinkMacSystemFont, 'San Francisco', 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif; font-size: 1.4em;\"\u003eArgo Navis digital setting circles\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003ewith ultra res 32K encoders\u003c\/h3\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/accessories\/ArgoNavis\/index.php\"\u003emore info\u003c\/a\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eServoCAT Goto Drive System\u003c\/h3\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.obsessiontelescopes.com\/accessories\/ServoCAT\/index.php\"\u003emore info\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Obsession","offers":[{"title":"Default Title","offer_id":49589023441155,"sku":"U2609-WB-18OBSESSIONUC","price":4500.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/B764E28D-63F8-48C3-8F8F-4DB1F636F118.jpg?v=1788910802","url":"https:\/\/milehighastro.com\/products\/used-18-obsession-ultracompact-dobsonian-w-nexus-dsc-and-servocat","provider":"Mile High Astronomy","version":"1.0","type":"link"}