2 Rosemary Lane, Sutton nr. Ely, Cambridgeshire, CB6 2NZ
Call us: 01353 776199 or 07990 646466
9:00am - 8:00pm GMT, 7 days a week
Email: sales@widescreen-centre.co.uk


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Sirius Observatories

We Challenge You to Find a Better Observatory!

Sirius Observatories are manufacturers of quality Astronomical Observatories which have been sold throughout the world since 1986.

All Sirius Observatories are made from extremely high quality materials, yielding a deterioration rate of only 0.1% per annum after 20 years under normal conditions, if properly maintained.  We can provide them in any colour, although most people choose white to keep things cool in the summer months.

For those that prefer a simple approach to life, the 2.3m and 3.5m can come in either a manual or a motorised version.  (The 5m and 6.7m are too large to operate manually.)  All sizes can have a Maxdome motor installed to co-ordinate the shutters; the dome rotation and the telescope direction.

Fiberglass Construction
We challenge you to find superior construction. With strong fibreglass construction the 'Sirius' Observatory provides the strength and characteristics of ocean going fibreglass yachts and marine craft. Fibreglass vessels are built from exactly the same materials. Sirius have added additional strength to return flanges, roof panels, doors and shutters of their Observatory. Designing and manufacturing with fibreglass provides clean and even flow lines that will not hold snow, ice and other debris. 

Weather Defiant
We challenge you to find better weather defense. We waterproof joints to all dome and wall panels and the seal is guaranteed for life! Because of the expensive equipment to be housed inside 'Sirius' Observatory have built waterproof joints to all dome and wall panels. This seal is guaranteed for the life of the product. The white outer shell provides the user with a 'warmer in winter' and 'cooler in summer' environment to enjoy both work and leisure.

Gelcoar Finishes
We challenge you to find a tougher finish. Sirius only use the best marine grade Gelcoat! This Observatory will appear as new, year after year in all weather conditions. There is never a requirement for painting the inside or outside of the product. When necessary, the use of a simple spray or wipe with fibreglass polish to the outside, will maintain the 'Sirius' superior clean lines. 

Factory Finished and Assembled
We challenge you to find a better fit and finish. Sirius observatories are pre-assembled and made fully operational at Sirius plant prior to shipping! Each panel and mechanical part is then numbered for ease of assembly. 

Dismantle and Reassemble
We challenge you to find more durable portability. Simply unbolt all the numbered parts and rebuild at your new location. It's easy with the 'Sirius' Observatory! No loss of valuable assets such as structural brick or stone walls. The walls are part of the observatory with a 'Sirius' Observatory. 

Models are avaiable for Amateur, Educational and Professional Astronomers.

Choose the size observatory to suit your needs:

Home Model - diameter 2.3m / 7'6"
School Model - diameter 3.5m / 11'6"
College Model - diameter 5.0m / 16'
University Model - 6.7m / 22'

Flexibility - choose dome with walls, or dome only with mounting ring.

High Wind Kit available 

  • Standard models withstand wind gusts up to 144 kph / 90 mph.
  • High Wind option withstands wind gusts up to 225 kph / 140 mph. 

 Dome and Shutter operation.

  • Easy to use hand operated dome rotation and shutter operation.
  • Motorised dome rotation and / or motorized shutter operation.
  • Pendant control of motor from anywhere inside the observatory.
  • Motorised dome rotation: clockwise and anti-clockwise.
  • Computer driven dome rotation and / or shutter operation - MaxDome. 

Instructions supplied for home assembly - Home and School Models. 


  • Solar panels installed with motorized option to re-charge 12v batteries. 
  • Mains battery charger 110 - 240v, optional. 
  • Night and Day Solar Vent available to circulate air. 
  • Excellent external finish - manufactured from marine grade fiberglass resins. 
  • Completely waterproof 
  • Stainless Steel fittings - corrosion free. 
  • Silent dome rotation - sealed bearings in urethane wheels. 
  • Wa​rranty - 12 months 


  • White exterior - colour variations optional.
  • Interior walls - dove grey. 
  • Interior dome - black. 

Dome and Shutter Motorisation and Automation 
There are three stages of dome rotation available. The basic form is to move the dome by hand. One finger will do the job on a 2.3m (7' 6") Home model, one hand on a 3.5m (11' 6") School model. 

The second stage is motorised - this adds a 12 volt DC motor which provides continuous clockwise or counter-clockwise rotation at the flick of a switch. The motor, gearing and battery are housed within a strong fibreglass case. This case is permanently bolted to the top of a wall panel within the observatory (or to the mounting ring in the case of a ‘Dome only' installation). The switch is on a long cable that allows you to stand beside your telescope in the center of the dome and rotate the dome in the direction of your choosing. The dome is driven by a laser cut toothed track - so no dome slipping. The motor is very quiet and can be powered from an AC transformer if you wish. Battery re-charging is via a solar panel (standard) located on a sealed platform outside the observatory and adjacent to the motor case. An optional mains-powered battery charger is available. 

The third stage is MaxDome which adds computer control to the dome rotation. The MaxDome software and controller card allows the shutter aperture to be "slaved" to the telescope position - hence the dome rotates to the telescope's position following a slew, and then tracks along with the telescope. MaxDome works by counting the revolutions of the dome drive shaft and using this in conjunction with the "geometry" of your dome and telescope mount to know where the aperture is. Obviously you must already have a motorised dome before you can add MaxDome to slave your 'scope to the shutter. 

In addition to dome rotation, these three stages apply to the dome's shutters as well. You can open them manually, you can have a motor open them at the flick of a switch, or you can have your computer open them (even from a remote location) with MaxDome. Once under computer control a cloud or rain detector can close them as well via a wireless FM radio link between the observatory wall mounted transmitter and the dome mounted receiver. 

 The lower shutter is opened and closed using a 12-volt worm-driven mechanical actuator with limit switches to ensure that there is no over-ride. In the School Model, the lower hinged shutter has an additional spring-tensioned rigid arm mechanism which provides stability in strong winds. 

The sliding upper shutter is operated by use of a 12 volt DC battery powered, positively geared drive. The motor, gearing and battery are housed within a strong fibreglass case which is permanently bolted to the dome and consequently rotates as the dome is rotated. By operating a toggle switch inside the dome, the upper shutter (which is independent of the lower shutter) can be opened or closed fully or stopped at any intermediate position. The battery, which powers the shutters, is charged via a solar panel situated on the outside of the dome. Again an optional mains-powered battery charger is available.