TALONS

 The Telescope ALert Operations Network System

Tying together all the elements

The internet has brought about great change in the astronomical community; but this interconnectivity is just starting to be exploited for use in instrumentation. Utilizing the internet for communicating between distributed astronomical systems is still in its infancy, but it already shows great potential. Full intelligent interconnectivity, through an elaborate TCP/IP framework, allows the system to operate in closed-loop mode.  In this mode of operation, the robotic network telescopes not only respond to alerts, but also extract information from the observations in real time and autonomously send it back to the network. Given the feedback of knowledge from other instruments, autonomous decision units (either central or at each telescope) can then command a modified response to optimize the information extraction.

The thinking telescope will tie into the Telescope ALert Operations Network System (TALONS), a network server that allows intercommunication of alert triggers from external and internal resources and controls the distribution of these to each of the telescopes on the network. The network is designed to grow, allowing any number of telescopes to be linked together and communicate. Coupled with an intelligent alert client at each telescope, TALONS can analyze and respond to each distributed alert based on the telescope's needs and schedule.

By closed-loop networking of even small aperture monitoring telescopes with rapid response telescopes into a worldwide distributed system, one can expect to extract a broad range of discoveries. Such a system could conduct the first comprehensive global census of stellar flaring, find unpredicted close encounters with nearby solar system objects, search for ”orphan” gamma-ray bursts, discover novae, and find the nearby supernovae needed to calibrate observational estimates of dark energy in the universe.

How we built the System (and Why)

When we began to put together the ideas for creating RAPTOR, we were faced with some hurdles that any communication software was going to have to surmount. Notably, we were going to have two wide-field telescope systems that were going to have to work in sync. Analysis brought up the following needs or requirements:

• Collaborative processing and room for additional future processing modules.
• Central hub communications due to bad width problems.
• The ability to add new telescopes to the system.
• Fast response time - Discovery->Processing->Alert in < 5 seconds.
• Bi-directional flow of information ( server <-> clients ).
• Support of existing GCN network protocols.

Once we researched the issue, we discovered that Distributed Sensor Network (DSN) design protocols would easily adapt to our needs. However, no one had put one together anything as elaborate as a system of telescopes. The DSN design principles, in general, supports easily growing and changing networks, fault tolerance, mosaic coverage of the environment, multiple instrument types, and temporal coverage.

Components

TALONS was built as a series of software tools to support the initial project and these could quickly be placed on any new system with little or no effort. This has proven to be the norm as we have now added three additional telescope systems without any significant changes to TALONS.

The components of TALONS are:

• TALONS Central - communication hub and processing unit

• TALONS Client - alert filtering and bi-directional communication library

• TALONS Injector - web-based, VOEvent-based injector that transmits manual alerts directly into TALONS and out to the VOEvent Network. All alerts from this method are archived by the TALONS database

• TALONS Monitor - web-based interface for the team to observe all network operations and client activities.

Constructional Principles

The TALONS system was built with C++ using Object-Oriented Design principles. C++ was chosen due to its versatility with hardware communications, ANSI compliance, and speed of processing. The code is built as a series of modules that can easily be added to whenever the need arises.

As more components for analysis, communication, or decision-making are needed to support the growing Thinking Telescope Project, TALONS can be adapted to match such needs.

Operational Ideals

TALONS Central spawns off a series of threaded processes, one for each line of communication to client types. Additional threads support incoming Injector and outgoing Monitor connections. Each thread is self-supporting and monitors and logs connections into the system. Some security is provided by IP monitoring by refusing all connections except from collaborators. The analysis modules run as separate processes. As collaborators need additional processing, other threads can be initiated. The TALONS Central program also notifies collaborators of events via e-mail, pagers, or cell phone tags, based on their interests.

The TALONS Client is a software library that can easily be linked into existing code (along with compiling provided header files). All documentation for tying existing code to the TALONS communication is also provided. A collaborator's individual needs can always be accommodated by the versatile nature of the software. The TALONS library is provided free to any collaborators of the Thinking Telescope Project. If you are interested in seeking a collaboration please contact the project.

The TALONS Client is compiled for your specific OS and kernel. Currently it is deployed only on Linux Systems (various kernels), but it can be built for Windows or Apple OSs. The Client handles all communication with the Central server. The collaborator merely has to set up configuration file parameters in order to tune the Client to match their needs. Once started, the library will maintain and monitor communications with TALONS Central, "hands free" of the user. Data is returned or received in easily readable numbers. Any complicated bit-wise triggering of flags is handled automatically by the system.

More information on TALONS can be found on on the Publications Page