To discuss the use of robots in the field of astronomy it is helpful to examine why levels of automation are beneficial to astronomers. The most basic use of a telescope is familiar to many people – one human observer using one telescope manually – i.e. putting eye to eye-piece and seeing the real light collected. Without the use of any computers, electronics or even electricity, this observing method can produce stunning images of, for example, the moon or nearby planets. Beyond manual observing, it is desirable to capture and store the images produced by telescopes for later analysis. In
current astronomy this is achieved by replacing the eye-piece with a high quality charge-coupled device image sensor – a digital camera. In addition to being able to accurately store the results, this has the advantage of being able to take long exposures which are necessary to image objects not bright enough to be visible with the naked eye. Once the observer is separated from the telescope by a digital camera there are advantages to using technology to perform other parts of the task such as the pointing of the telescope and tracking of the target object (constantly moving the telescope to keep the object static on the image frame, compensating for the Earth's rotation). With robotics controlling pointing and tracking, and a digital camera taking the images, there is no need for the astronomer to be physically located at the telescope during normal operation. This level of technology has enabled home amateur astronomers to sit inside a warm house at the end of a collection of long cables to their telescopes outside – a definite advantage for cold nights in countries such as the U.K!
Within professional astronomy, telescopes with this level of automation can be used for remote observing (Baruch 1992) by allowing researchers to control telescope systems and verify returned data over a communications link. Using computers at their home location to contact remote telescopes saves researchers travel time and cost. Scheduling and reorganising time on telescope installations can be much more flexible if researchers do not have to travel to it, but instead can make use of observing time with little notice. An example of an installation of this type is the Astrophysical Research Consortium telescope in New Mexico (Loewenstein et al. 1994), constructed for remote observing use by students at several universities. It was contactable over the Internet or by calling it directly with a modem, and controllable using bespoke software.
Many types of research programme involve repeatedly imaging the same celestial coordinates in order to observe changes over time, for instance in the study of variable
stars. This type of study benefits from the next more advanced level of telescope automation – automatic telescopes. They can perform the repetitive and uninteresting work of repeatedly imaging patches of sky at predefined times. Automatic telescopes take a list of observations to perform and work through them using automated telescope pointing, tracking and imaging hardware. Typically a human operator oversees the creation of the work list and is responsible for starting the telescope at dusk and stopping the telescope at dawn or during bad weather. The STARE telescope (Alonso et al. 2004) in Tenerife runs automatically throughout the night but depends on a human operator to start and stop the telescope systems, to open and close the dome and to monitor the weather conditions to decide if observing is possible.
Different levels of automation can be achieved between automatic telescopes and fully autonomous robotic telescopes, however it is the latter which this thesis focusses on. A fully autonomous robotic telescope requires no human present for normal observing duties, start-up and shut-down. The only reasons for a human to visit a fully autonomous robotic telescope would be in the cases of hardware failure, regular servicing, system upgrade or hardware configuration change. A system of this type must accept requests for telescope time from users but then must optimise the order in which it completes the work itself. It must be aware of its environment, starting operation at dusk and stopping operation at dawn (in the case of a nocturnal telescope). It must be aware of the weather on two levels – it must protect itself from weather which could cause damage, e.g. rain, but also must evaluate the seeing conditions to determine if observing would create good quality data. One factor involved in this decision is the presence of cloud – it would not be dangerous for the system to open the dome in cloudy conditions, however, no useful observations could be made. Having made its observations the telescope systems must return the data collected back to the users.
A fully autonomous robotic telescope can work tirelessly taking no breaks – starting operation as soon as weather and seeing conditions allow, and only stopping at dawn, providing a very efficient way to service a lot of users.
The Berkeley Automatic Imaging Telescope (Richmond et al. 1993), constructed between 1989 and 1992, was a fully autonomous robotic telescope. It had a weather station to monitor its environment and it had several control computers to operate all the different telescope systems. However, the time of construction pre-dated the World Wide Web, as such only a minimal interface between users and the robot was created – it accepted observing requests by email in a format not overly complicated, but one which required some skill to write. The system notified users of completed observations by email, the results were then downloadable using the Internet File Transfer Protocol (FTP) (Postel & Reynolds 1985).
This thesis is based around a project to create a Web interface to the Bradford Robotic Telescope in Tenerife. However, this is not the first incarnation of the Bradford telescope project, the predecessor to the this project is the Bradford Robotic Telescope in Oxenhope (Cox & Baruch 1994; Baruch 1995; Baruch & Cox 1996; Baruch 2000) which was constructed between 1990 and 1993 (Baruch 2009) and featured a public interface on the new World Wide Web. The Oxenhope telescope was fully autonomous, only communicating with the outside world twice daily – once to transfer requests for service to the telescope at dusk, and once at dawn to transfer the results. The Oxenhope project attempted to answer some of the questions investigated in this thesis with the technology available at the time. This thesis examines new solutions to the challenges utilising the vast technological developments made since the Oxenhope telescope was constructed (Tallon et al. 2003).