Exploring the sky with the Digital Telescope (DigiT)

The Digital Telescope (DT) is a large array of small stationary telescopes which, in essence, produce a movie-like data stream of the entire visible sky. The telescope detectors are run at sub-second cadence (to minimize the effects of star trailing within each image), and sidereal tracking is achieved in software - hence the name Digital Telescope. This novel concept is quite different to a traditional telescope where motorised mechanisms are needed to make the telescope usable. Eliminating telescope movement greatly simplifies the mount requirements, and allows them to be packed tightly together. The DT uses commercially off the shelf equipment to minimise construction and maintenance costs. Software is key to a viable DT, with the main challenge being the data management and real-time reduction, but we can already demonstrate a fully functional real-time pipeline. The DT is able to cheaply monitor the whole visible sky to 20-21st magnitudes (cosmologically interesting sensitivities), detecting explosive, moving, and variable objects in near real time - including those in the near-Earth environment.

We propose to build a prototype version of the DT that is capable of continuously monitoring an area of 134? × 7? using low noise scientific CMOS detectors. The sub-second cadence enables measurements of bright objects while greater sensitivity for fainter objects is obtained by stacking observations. This enables photometry of 20-21st magnitude objects at a cadence of 400 s. As the software stacking can be applied at any rate and along any vector, synthetic tracking/stacking of both stars and satellites (moving along any trajectory) is possible. Therefore, the same dataset can be used for both astronomical research via sidereal tracking or Space Domain Awareness (SDA) by tracking using satellite orbital elements. Additionally, by blind-stacking data along different trial vectors and rates, small (i.e. faint) and previously untracked space debris can be detected and catalogued. This prototype will demonstrate the capabilities of this novel concept and overcome the remaining challenges in constructing/operating an all-sky DT.