Thinking About a New Scope? Think Big!


Made in the USA



15" f/4.2 UC (Ultra Compact)

18" UC

  • Stacked for transport 22” x 22” x 20” high
  • Weight of heaviest component is 45 pounds
  • Eyepiece height at zenith is 59 inches
  • See more Specifications

15" UC includes:

M13 comparison

Cloudy Nights review

Cloudy Nights Gear of the Year 2008


15UC in a tiny car!

15UC in a tiny car!

The views in the scope are great, and I love the fact that it tucks easily into my sports car, a Toyota GT-86. It was a big hit at the Bryce Canyon festival this year.
Michael Carnes 15UC
Cottonwood Heights, Utah

15" f/4 UC$7,495

Plus Shipping & Crating

43% more light gathering power than a 12.5"

The 15" f/4 UC is a revolutionary design. It is a large aperture telescope that collapses into a very small package. If you have limited hauling or storage capacity, (like the trunk of a small car) then this is the scope for you.

Our revolutionary Virtual Mirror Box (VMB) is the foundation of the UC design. It is a welded steel framework made from NC laser cut steel. It provides four main functions. It provides the primary mirror cell, the altitude bearings, the connection points for the truss poles, and a retainer for the wheelbarrow handles. To keep it as ultra compact as possible, the side bearing portion is foldable to reduce the height of the VMB by half.

In the transport mode the clearance height is a mere 12 inches. Or place the VMB (Virtual Mirror Box) next to the rocker in your car and reduce the height even more. Now everyone can have a big aperture scope and take it to their dark sky site. This telescope will appeal to those that like the ultimate in form follows function style. Low eyepiece height means 100% of observing will be done with your feet on the ground. Or pull up a stool and enjoy some sit down observing in the lower half of the sky. The UC is all black with a modern space frame construction. If your vehicle is small or you intend to put it in the trunk, then the Ultra Compact is the obvious choice. And if you want the ultimate in Dobsonian evolution, the Obsession Ultra Compact 15" is it.

No compromises. The UC uses the same proven design criteria and materials that made the Classic Obsession so successful and the most copied larger aperture dob on the market. We use the same premium optics from Ostahowski and OMI that we do in our Classic series of telescopes. Diffraction limited and all figured and tested with interferometry. Ion deposition 96% enhance primary coating. Two inch flex free glass. One tenth wave 96% Diamond brite secondary mirror. As with our Classic series, you cannot get better optics at any price anywhere. Ostahowski and OMI are so confident of their quality that they post the serial number and test data for ever mirror they make on their web sites for everyone to review. Nobody else does this.

Dave Kriege gives Tom Trusock a walk-through of the Obsession 15" Ultra Compact (video courtesy of Cloudy Nights Telescope Reviews)

4 times the light gathering power of an 8 inch Schmidt-Cassegrain Obsession
15" UC
Limiting stellar magnitude: 15.5 14.0
Rayleigh Resolution Limit: 0.36
arc seconds
arc seconds
Contrast limit:
(minimum diameter before a
nebular object fades from view)
arc minutes
arc minutes

"An increasing number of amateurs are driving to dark sites for visual sessions, and as always, space is at a premium. For many, that means the new Obsession UC line is just the ticket. Following on the heals of the 18" UC, Kriege and company introduced the 15" Ultra Compact in 2008. These scopes are designed to pack the most aperture into the smallest package possible, and the 15" makes it even smaller yet."

Tom Trusock - Cloudy Nights Reviews

Customer Comments

First Light at OzSky star party in Australia

October 30, 2016

15" UC Obsession

First Light at OzSky star party in Australia with Lachlan M and Richard X. OzSky is THE premier event in the Southern hemisphere. Attendees have access to ten Obsession telescopes that they can use all night for a week!

Read more 15" UC customer comments

Amir Abramovich in HaSolelim Israel

15" UC Obsession

Hi Dave,
Just to let you know that my scope is a joy to use. Simple and quick setup and great views. - Amir A, Negev desert, Israel

Read more 15" UC customer comments

Mike C. in Phoenix, Arizona

15" UC Obsession

Views are great! Gave me my best observing of the Lagoon, Orion, Helix, etc. With the increased aperture I can use filters without the image getting so faint that it's hard to see. Shorter focal length gives me wider views of open clusters, etc. than I was getting with my C11.

Easy to transport too! My wife watched me pack it into the SUV for a star party and remarked "wow, that really condenses down!"

Short height means I don't need a ladder either.
I'm happy!!

Mike C.

Read more 15" UC customer comments

15" UC Photos

15" UC
15" UC
15" UC
15" UC
15" UC

photos courtesy of Tom Trusock

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15" UC vs 15" Classic

Obsession 15" UC

Obsession 15" Classic

Eyepiece height at zenith 59 inches (150 cm) 66 inches (168 cm)
Set up time including nylon light shroud Same for both
Ease of use (setup, take down, collimation) Same for both
Ease of Motions (hand guiding) Same for both
Construction/materials Same for both, except:
components covered with satin black laminate components are stained and have six coat polyurethane finish
Bearing geometry and surfaces Same for both, Ebony star on etched virgin Teflon
Light baffling Classic is better with 360 degree upper tube assembly baffle. UC 160 degree baffle opposite focuser. Views and contrast are identical unless there is a nearby street light in the area. If you only observe in the city at home then the Classic is the better choice. If you like to take your scope to a dark site the UC is an excellent choice, especially if you drive a sedan or have limited transport space.
Optics (OMI) (Ostahowski does not offer anything under 18 inches) f/4 primary mirror requires a Paracorr coma corrector for optimum views. f/4.5 Paracorr optional but not needed.
Secondary mirror Same 2.6 secondary mirror for both. Central obstruction and image contrast the same for both under good skys.
Coatings Same for both. 96% on primary, 96% on secondary
Mirror cell Same for both, 9 point
Wheelbarrow handles Standard on both
Truss poles Six 1 inch diameter. Connected in pairs at apices. Eight 1.25 inch diameter. All eight separate.
Stability UC has 6 pole design and Baltic Birch steel reinforced segmented bearings. Much less mass than Classic. Eight pole design and one piece cast aluminum side bearings. Mirror box and rocker have more mass. Total weight is about 25 pounds heavier than the UC. Classic is a better choice for CCD imaging.
Dimensions for transport 22" x 22" x 11" high. Includes virtual mirror box nested in rocker (will fit in most trunks or hatchback). 23" x 23" x 25" high (rocker and mirror box) Upper tube assembly placed next to lower unit.
Upper Tube Assembly weight (with Feathertouch focuser) 6 pounds 9 pounds
Weight of heaviest component (includes 2 inch thick standard thickness mirror) 45 pounds. Includes the virtual mirror box, mirror, and dust cover 60 pounds Includes mirror box, mirror, and dust cover.
Weight at wheelbarrow handles about 8 pounds about 9 pounds
Weight of complete scope about 65 pounds about 90 pounds
Clearance width required with wheelbarrow handles attached.
(or minimum size of doorway needed to roll in or out with wheels attached)
27 inches

Clearance width needed when carrying UC virtual mirror box is 21 inches.
26 inches

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15" UC Specifications:

Metric info shown in italics

Primary Mirror:

  • 15" - 381 mm Ostahowski, or OMI 2 inch thick mirror
  • Fused silica glass standard on all 15" UC primary mirrors.
  • 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:

  • Pre-installed
  • 2.6" - 66 mm United Lens 1/10 wave or better
  • Interferogram included
  • 96% reflectivity at 550 nm
  • Super enhanced Brilliant-Diamond non-fading multi-dielectric coating

see Optics page for more info

Focal Length:

  • 60" (± 2") - 1,520 mm (± 50 mm)

Eyepiece Height at Zenith:

  • (approximately) 59" - 150 cm

Mirror Cell:

  • 9 point

Truss Pole:

  • Length: 45" (± 2") - 114 cm (± 5 cm)
  • Diameter: 1.25" - 32 mm
  • Wall Thickness: 0.035" - 0.9 mm

Upper Assembly:

  • Diameter: 19" - 48 cm
  • Height: 10" - 25 cm
  • Weight: 6 lbs. - 2.7 kg

Lower Assembly:

  • Virtual Mirror Box stacked in Rocker for Transport
    22" x 22" x 21" high

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Standard Features and Accessories:

Feathertouch focuser by Starlight Instruments

Feathertouch on UC

Standard on all Ultra Compacts

Low profile, Crayford type, 2 inch focuser, with 1-1/4 inch threaded adaptor for filters. Compression rings. Can be swiveled on it's base to the most convenient position. A joy to use and beautiful to look at.


Standard on all Ultra Compacts

Upper and lower light baffles

Standard on all Ultra Compacts

Counterweight kit

Standard on all Ultra Compacts

Wheelbarrow handles

Comes standard on all Obsessions 12.5" through 25" at no extra charge.

Primary Mirror Coating

Enhanced Aluminum - 96% reflectivity, with dielectric overcoat (a supreme coating) standard on all primary mirrors. See Optics page for more info.

Secondary Mirror Coating

An 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.

With 96% enhanced on the primary and our standard 96% Brilliant Diamond secondary, the optical system is equivalent to an extra 2" of aperture!

12 volt cooling fan

telescope mirror cooling fan

12 volt cooling fan comes standard on all Classic and Ultra Compact scopes.

Fused quartz

15” UC Obsessions use fused quartz for the primary mirror glass.

more info

Optional Accessories:

See the Accessories page for more info on these items


$475 (Highly recommended at f/4.2)

Ripstop Nylon light shroud

(Highly recommended)

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 ultra res 32K encoders

more info

ServoCAT Goto Drive System

more info

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.

Pre-installed (if ordered).

more info

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Ordering Information:

A Deposit is required to place an order ($1,600 for 15" UC)

Mail the deposit to:

Obsession Telescopes
PO Box 804
Lake Mills, WI 53551

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.