Vycon Products, Ltd.
Offers the fiberglass Voyager Observatory, with an approximate 8 foot inside diameter, suitable for instruments up to 16 inches in aperture.
http://www.observatories.co.uk/

Galactica 360
Fiberglass, non-rotating observatory domes and freestanding observatories for amateur astronomers. Domes feature a counterweighted clamshell design. Also manufactures a unique portable bandstand.
http://www.galactica360.com/

NorthSheds
Canadian manufacturer of roll-off roof observatories and telescope piers. Also sells observatory plans and kits.
http://www.skyshed.com/

Ash Manufacturing Company
Produces the Ash-Dome line of observatory domes and tracking instrument shelters for advanced amateur observatories, professional observatories and government agencies.
http://www.ashdome.com/

Astro Domes
Telescope observatory domes for the home and serious astronomer. Site features specifications, photos and plan views of each product.
http://www.astrodomes.com/

Meridian Controls Corporation
Specializes in observatory dome automation and turn-key observatories. Slaving of the dome to telescope motion is accomplished using software from Software Bisque.
http://www.meridiancontrols.com/

Observa-DOME Laboratories, Inc.
Professional observatory domes, missle tracking and LIDAR shelters for advanced amateur, professional and government applications.
http://www.observa-dome.com/

Pier-Tech, Inc.
Unique, adjustable height telescope piers that preserve polar alignment during height adjustment. Company also manufactures the Tele-Station roll-off roof observatory.
http://www.pier-tech.com/

Sirius Observatories
Australian manufacturer of astronomical domed observatories, and the ATS Autodome controller system featuring a serial interface for control by TheSky software.
http://www.siriusobservatories.com/

Astro Haven
Fiberglass clamshell domes for observatory, planetarium, radar-tracking housing, portable bandstand. (Example of site to be moved to this category.)
http://www.astrohaven.com/

Technical Innovations, Inc.
Fiberglass Home-Dome, Pro-Dome and Robo-Dome observatory domes, Dome Works and Digital Dome Works control hardware, and Robo-Focus remote focusing hardware with software. Free publications on how to design and set up a remote controlled observatory.
http://www.homedome.com

Stargazer Planetariums
Custom-built inflatable domes for mobile planetarium shows, mobile theatres, promotional shows and other uses.
http://www.stargazer-planetariums.co.uk/

Alexander's Observatories
Provides fully installed rolling roof observatories, plus Shockproof easy-Level Pedestals (permanent piers) for a variety of telescopes. Located in the UK.
http://www.alexandersobservatories.co.uk/