RTML

Options and Brokers using RTML capability on the LT. © 2020 LT Group

Introduction

As an alternative to using the Phase2 Interface, the Liverpool Telescope is able to process observation requests using the Remote Telescope Markup Language" (RTML) protocol. This XML based language is used to remote-control telescopes, or to communicate with autonomous robotic telescopes. RTML is most powerful for integrating LT observations into automated systems, removing the requirement for each group to be entered by hand in the Phase2 database.

The RTML method of sending observations to the telescope automatically creates groups in the Phase2 database, and will be suitable for the majority of observations. This method has been used to integrate the Liverpool Telescope into the GROWTH Marshal network and also to develop a Liverpool Telescope module for the TOM Toolkit

NOTE: Despite covering most use cases, users will still need to use the fully featured Phase2 Interface tool for observations requiring any of the following features;

  • Phased, Minimum Interval or Monitor Timing Constraints
  • Defocussing of the telescope
  • Specific Sky Rotation Angle
  • Non-sidereal Tracking
  • Observations without autoguider

RTML-capable instruments

RTML capability is currently available for the following instruments.

MOPTOP and RISE are planned to be RTML enabled in the future.

Options for using RTML

We provide two different ways to use RTML to send your observation details to the LT. Like the Phase2UI, both of them insert the information straight into the phase 2 database. The advantage however is that they allow you to automate the Phase 2 process, particularly useful if you have automated pipelines for followup. The two RTML interfaces are:

  • Python module - ltrtml
    • Simple setup of Target, Constraints and Instruments in dictionaries
    • Commented, Example Code for all supported instruments
    • Functions for submitting observations and cancelling observations
    • Error handling with error strings returned for logging
    • Easy to integrate into Python based observing systems
  • Java Based RTML Create and Send tool
    • One tool to generate the RTML, and another to send the RTML directly to the LT
    • Can be incorporated into customised scripts and programs

Rapid-response overrides

Both RTML interfaces can also talk directly to the Target of Opportunity Control Agent (TOCA), the system that triggers the LT's rapid-response capability to interrupt the current observation and immediately observe your target instead. The LT already performs completely autonomous instant overrides for Gamma-Ray Burst alerts via a different protocol from the NASA Gamma-ray Coordinates Network (see GCN in diagram above), but a similar end result is also possible via RTML/TOCA.

Overrides can be very disruptive, and the ability to use the TOCA is restricted to only essential proposals. It is requested at the Phase 1 stage and approved by the TAC.

Applying for RTML capability

The RTML facility is available to all users who have TAC-awarded time allocations. Please contact us for more information on usage.