First results of the Test-Bed Telescopes (TBT) project: Cebreros telescope commissioning

TL;DR

The paper reports on the initial commissioning and performance evaluation of the TBT Cebreros telescope, a robotic system designed for space object detection and tracking within ESA's SSA program.

Contribution

It presents the first operational results of a fully robotic telescope prototype for space situational awareness, including site assessment and performance metrics.

Findings

Residual astrometric errors under 0.5 arcseconds

Satellite residuals around 1 arcsecond

Survey depth exceeds magnitude 18.5 in 30s exposures

Abstract

The TBT project is being developed under ESA's General Studies and Technology Programme (GSTP), and shall implement a test-bed for the validation of an autonomous optical observing system in a realistic scenario within the Space Situational Awareness (SSA) programme of the European Space Agency (ESA). The goal of the project is to provide two fully robotic telescopes, which will serve as prototypes for development of a future network. The system consists of two telescopes, one in Spain and the second one in the Southern Hemisphere. The telescope is a fast astrograph with a large Field of View of 2.5 x 2.5 square-degrees and a plate scale of 2.2 arcsec/pixel. The tube is mounted on a fast direct-drive mount moving with speed up to 20 degrees per second. The focal plane hosts a 2-port 4K x 4K back-illuminated CCD with readout speeds up to 1MHz per port. Detection software and hardware are optimised for the detection of NEOs and objects in high Earth orbits (objects moving from 0.1-40 arcsec/second). Every night it takes all the input needed and prepares a schedule following predefined rules allocating tasks for the telescopes. Telescopes are managed by RTS2 control software, that performs the real-time scheduling of the observation and manages all the devices at the observatory.1 At the end of the night the observing systems report astrometric positions and photometry of the objects detected. The first telescope was installed in Cebreros Satellite Tracking Station in mid-2015. We evaluate the site characteristics and the performance of the TBT Cebreros telescope in the different modes and strategies. Average residuals for asteroids are under 0.5 arcsecond, while they are around 1 arcsecond for upper-MEO and GEO satellites. The survey depth is dimmer than magnitude 18.5 for 30-second exposures with the usual seeing around 4 arcseconds.