Just your size. Large Aperture, no big ladder needed! Our most popular model.

Orders received after July 1st - price will be $6,295. The Obsession 18 is the ultimate compact scope for the discriminating enthusiast who wants big aperture in a small package. There are no short cuts in construction or performance. The Obsession 18 features the same quality craftsmanship and award winning design as found on our renown 20, 25, 30 and 36 inch telescopes. A 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. We've done our homework - the 18 is easy to set up and a joy to use. Fantastic deep sky and planetary images. One look and you'll re-learn what it means to be excited about astronomy.

M104 - larger image Exposure time: 30 x 60 sec.

M51 - larger image Exposure time: 15 x 90 sec.

NGC 4656 - larger image Exposure time: 15 x 3 min.

	18" Specifications: Metric info shown in italics Primary Mirror: 18" - 457 mm GALAXY, or OMI 2 inch thick mirror 96% reflectivity Enhanced Aluminum Coating and Dielectric Overcoat (a supreme coating) Center marked for precise collimation plus Interferometry certification see Optics page for more info Secondary Mirror: 3.1" - 79 mm United Lens 98% reflectivity at 550 nm. Super enhanced Brilliant-Diamond non-fading multi-dielectric coating see Optics page for more info Focal Length: 81" (± 2") - 2060 mm (± 50 mm) Mirror Cell: 18-point Truss Pole: Length: 55" (± 2") - 140 cm (± 5 cm) Diameter: 1.25" - 32 mm Wall Thickness: 0.035" - 0.9 mm Upper Assembly: Diameter: 22" - 56 cm Height: 12" - 30 cm Weight: 9 lbs. - 4.1 kg Lower Assembly: (see diagram): A= 26" - 66 cm | B= 27" - 68 cm | C= 21" - 53 cm | D= 25" - 63 cm Mirror Box weight: (what you don't lift): 80 lbs - 36 kg Weight at Handles: (what you do lift at Wheelbarrow handles): 18 lbs - 8 kg Eyepiece Height at Zenith: (approximately) 6' 5" - 198 cm COMPARISON 5 times the light gathering power of an 8 inch Schmidt-Cassegrain Obsession 18" Typical 8" Limiting stellar magnitude: 16.0 14.0 Rayleigh Resolution Limit: 0.31 arc seconds 0.68 arc seconds Contrast limit: (minimum diameter before a nebular object fades from view) 4.8 arc minutes 11.0 arc minutes

Mirror Options: see the Optics page for more info Obsessions are built with premium diffraction limited optics from Galaxy and OMI (Optical Mechanics Inc.). Choose from Galaxy or OMI mirrors when ordering. Obsessions are also available without optics if you already have your mirrors. Call, fax, or email for price and delivery.

• Choose from four great focusers
  The JMI EV3 comes standard on all Obsessions. Or upgrade to the EV1, or EV1 with motofocus, or the awesome Feathertouch by Starlight Instruments. See the Focuser Options page for more focuser options
  
  
• Wheel Barrow handles
  Comes standard on all Obsessions 15" through 30" at no extra charge.
  They're not necessary on the 12.5".
  
  
• Primary Mirror Coating
  Enhanced Aluminum - 96% reflectivity, with dielectric overcoat (a supreme coating) standard on all primary mirrors.
  
  
• Secondary Mirror Coating
  An Obsession exclusive - Super enhanced Brilliant-Diamond is standard on all Obsession secondary mirrors. This premium multi-dielectric coating has 98% 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.
  
  With 96% enhanced on the primary and our standard 98% Brilliant Diamond secondary, the optical system is equivalent to an extra 2" of aperture!

Optional Accessories:
See the Accessories page for more info on these items

• Telrad
  
  
• Ripstop Nylon light shroud.
  
  
• Barlow-Laser Collimator 2" barrel. Highly recommended. Includes 2" magnetic barlow lens and mask for the new barlowed laser collimating technique. Great visual aid and no better way to accurately align fast Newtonians. learn how
  
  
• Argo Navis digital setting circles with super res 10K encoders. more info
  
  
• ServoCAT Goto Drive System. more info
  
  
• Counterweight kit - (you supply the lead shot or sand) Recommended if you intend to use heavy barlow/eyepiece combinations, a Paracorr coma corrector, a traditional finderscope, or the Argo Navis digital setting circles.
  
  
• Dew heater for secondary mirror - Secondary mirror heating system automatically senses the air temperature and the mirror temperature, then maintains the secondary at a preset (adjustable) temperature above the ambient air temperature to prevent dewing or icing. more info

Ordering Information:
A Deposit is required to place an order ($2,000 for 18").

Mail the deposit to:
Obsession Telescopes
PO Box 804
Lake Mills, WI 53551
USA

You can e-mail your order, or mail it with the deposit.

• With your order, please list any options and/or accessories you want, your mailing address, e-mail address if any, and phone number(s).
  
• After we receive it, we will send you an order confirmation letter.
  
• Delivery is usually 1 to 2 months from time of order.
  
• Please e-mail for current delivery times.
  
• Balance due prior to shipment.
  
• Prices do not include shipping and crating. We ship throughout the world via UPS.
  
• Any questions, please call or e-mail.
  
• NOTE 10% order cancelation charge.