Facility

Dome observatory

Omega Observatory is built around a 5.5 metre motorized observing dome and a permanently installed telescope system. The construction provides a stable mechanical foundation for the instruments while the dome, mount and technical systems can be controlled and monitored both locally and remotely.

The Omega Observatory dome with its shutter open — ScopeDome 55M with the shutter open and the telescope system in observing position.

At a glance

Type: Dome observatory
Dome: ScopeDome 55M with full automation equipment
Dome diameter: 5.5 m
Base-ring diameter: 5.0 m
Total height: 4.9 m
Dome height: 3.8 m
Base height: 1.1 m
Shutter opening: 1.7 m
Dome weight: 1,500 kg
Construction: Polyester and glass-fibre laminate
Full rotation time: Approximately 252 seconds
Shutter opening time: Approximately 60 seconds
Telescope pier: Baader Heavy Pillar
Mount: 10Micron GM 4000 HPS II
System integration: ASCOM-compatible
Operation: Local and remote operation

Mechanical foundation

Foundation and telescope pier

The observatory is built on an insulated reinforced concrete slab with a drained and compacted load-bearing layer. At the centre of the slab the foundation is locally deepened and reinforced for the telescope pier.

The construction gives the telescope system a stable mechanical foundation with high load-bearing capacity. The telescope system is permanently installed on a Baader Heavy Pillar, anchored to the reinforced central part of the concrete foundation.

Dome

Dome and mechanics

The observatory is equipped with a ScopeDome 55M with full automation equipment. The dome is a segmented polyester and glass-fibre laminate structure. The rotating section runs on a system of guide rollers and is centred against the permanent base ring.

The observing aperture has a separate motorized shutter running in dedicated guides. Dome rotation and shutter movement have independent drive systems and are monitored by position and limit sensors. A home sensor establishes the dome reference position while an encoder provides continuous position tracking.

The observatory also has a separate lockable entrance door integrated into the dome base, providing direct access without using the observing aperture as a passage.

Telescope system

Mount

Both telescopes are carried by a 10Micron GM 4000 HPS II, a permanently installed German equatorial mount designed for large instruments and high pointing and tracking precision. The mount is rated for an instrument payload of up to 150 kg. The Newtonian reflector and refractor are mounted in parallel and therefore form one fixed telescope system.

The HPS system combines a high-precision worm-gear drive with absolute encoders mounted directly on both axes. The encoders provide more than 10 million interpolated increments and a resolution of approximately 0.1 arcsecond. Because the actual position of each axis is measured directly, the control system can compensate for periodic error and other mechanical errors in the transmission.

The mount also uses a model of the sky and telescope system with up to 100 reference points. The model is used to correct pointing and tracking for effects including small polar-alignment errors, orthogonality errors, repeatable flexure and atmospheric refraction. For the GM4000 HPS II, the manufacturer specifies typical tracking accuracy of about 1 arcsecond over 15 minutes and approximately 0.6 arcsecond RMS with the internal 25-star model and compensation for system flexure and polar-alignment errors.

Operation

Control, automation and safety

The observatory can be controlled both locally and remotely. Remote operation provides flexibility to select the working method according to the observation and practical conditions. Dome rotation and the observing shutter are motorized and integrated with the observatory control system.

The facility is equipped with sensors for cloud, rain, temperature and relative humidity, as well as dome position, limit states and telescope park position. During remote operation the automatic safety functions are enabled, allowing the observatory to initiate a safe closure when monitored conditions require it.

Technical infrastructure

Electronics and operating environment

The control and power equipment is installed in separate enclosures for dome control, shutter operation and telescope-system power. The electronics enclosures are monitored by hygrometers and have controlled heating to limit moisture and condensation around sensitive electronics.

The dome rotation and shutter motors include temperature monitoring and motor heaters to provide stable operating conditions at low temperatures. The facility has permanent electrical power and a fixed broadband connection for control, monitoring and remote access. Observatory equipment can also be switched on and off remotely.

Working environment

Lighting

The observatory has separate red lighting for use during observations, helping preserve dark adaptation as far as possible, and white working light for servicing and maintenance.