Astronomical Instruments at the UOAO

The University of Athens Observatory hosts a 0.4-m Cassegrain reflector inside the 5-m dome.

The main characteristics of the telescope are:

Cassegrain reflector (CCT-16, DFM ENGINEERING INC., USA) with primary mirror 0.4-m.
Focal ratio f/3 for primary mirror and effective focal ratio f/8 for the telescope. Both primary and secondary mirrors have a pyrex substrate and are aluminized with a silicon monoxide overcoat.
The focal plane position is between 0 and 20 cm from the instrument mounting surface.
The focus may be either manually controlled or commanded by the control system with a 2-speed motor.
Low temperature (-40 °C) operation for the optical encoders.
Finderscope: 9 × 60 with illuminated reticle.

Equatorial fork mount.
RA and DEC axes driven by DC servo motor/encoders for fast response and low power consumption.
Combination of steel and aluminum construction for responsive and long lasting performance.
Tracking accuracy: ±2.0 arc seconds in 2 minutes, ±20.0 arc sec in 1 hour.
Pointing accuracy (with refraction and alignment correction) better than 1 arc minute RMS.
Optical incremental position encoder drives are independent of the motor drives to provide excellent pointing.
Cool operation - very low heat generation at telescope (less than 10 Watts average).
High acceleration and deceleration rates for fast pointing to the object.
Variable slew, set, guide and tracking rates: 0 to 4 deg/sec.
Pedestal allowing elevation and azimuth adjustments for polar alignment.
Supports 20 kg instrument behind mounting surface.

The Telescope Control System (TCS) provides a user-friendly interface to the telescope. Utilizing an IBM-compatible PC with a simple DOS 6.0 operating system, it provides continual position display, status reporting, and an easy-to-use, menu driven command set the pointing model corrects for precession, nutation, aberration, atmospheric refraction, mount misalignments and flexure.
Control electronics may be located up to 50 m from the telescope (control room).
Development and application software plus source code are licensed to user for long-term maintainability.
28 commands provide complete control of telescope and dome.
Built-in library of astronomical objects.
Compatible with commercial auto guider systems.
Operates and displays in any Epoch.
Hybrid digital/analog servo controller with zero position error integrator.
Extensive system protection via computer-calculated limits.
Hand paddle functions include: guide, set, slew, focus and dome right-left.
Horizon limit switch enhances system safety by preventing telescope over-travel.
Remote dome monitor and keyboard for public night viewing and instruction where direct access to telescope is required.
Dome control using existing motor.

The 0.4 m f/8 Cassegrain telescope at the University of Athens Observatory had its first light on November 1999. For the first 12 years of operation (2000-2012), the observations were carried out in semi-automatic mode, with the absolute need of an observer being at the control room and/or inside the dome. Since August 2012 the telescope and dome can be fully controlled remotely, after small electro-mechanical modifications on the existing robotic configuration by Dr. K. Gazeas. Such a modification can guarantee photometric observations at UOAO from any remote location, through internet connection.
The University of Athens Observatory is the first robotic and fully remote controlled telescope operating in a Greek Institute.

Imaging CCD camera ST-8 (SBIG).
Imaging CCD camera ST-8 XMEI (SBIG).
Imaging CCD camera ST-10 XME (SBIG).
Medium-Resolution Stellar Spectrograph (UOAO-MRS) with a dispersion 61 Å/mm (0.5 Å/pixel) and resolving power R=10000 (built by Dr. D. Papathanasoglou and Dr. K. Gazeas in the Laboratories of Astronomy and Applied Optics of the Section of Astrophysics, Astronomy and Mechanics, at the University of Athens).
SPP3 single channel Photon Counting Photometer.
Fully computerized Pulse Counting Photoelectric Stellar Photometer.
Solar filter, focal reducer, smaller CCD guiding cameras etc.
Small reflecting and refracting telescopes, used on public nights or for wide-field CCD imaging and photometry.

Gerostathopoulio - University of Athens Observatory