NRAO Home  >  Green Bank  |  Wiki Topic:    GB > Observing > StandardObservingModes

Changes | Index | Contents | Search | Go

GBT Standard Observing Modes

1. Introduction

This document describes standard observing modes used on the Green Bank Telescope (GBT). The document serves several purposes. Potential GBT observers may use the list of observing modes to determine whether their projects fit within standard use cases. Scheduled observers may find templates for their observing configuration available here. Developers may use this document as a checklist of capabilities which need to be supported in new projects, e.g. an observing API.

A typical observing session on the GBT begins by configuring the antenna and electronics system using the GBT configuration API, or config_tool. The config_tool takes a series of parameters which describe the receiver to be used, the backend, the frequency ranges to be observed, etc. Following the successful execution of a configuration script, the user proceeds to run observations using GO, a Glish program which allows the observer to specify source name, position, and observing parameters. GO is currently being deprecated in favor of the new Python-based Observing API, called TURTLE. The GBT observer's interface will ultimately provide a seamless convergence of the configuration, observing, and monitoring aspects of telescope operation.

2. Assumptions

• The observer is using the GBT either as a single dish telescope or as an element in a VLBI array.
• The GBT is fully functional, with no special restrictions due to equipment availability, weather, or RFI environment.
• The observer is using the config_tool to set up the antenna and electronics (this will change when we observe with Scheduling Blocks; the documentation will be updated at that time).
• All components are being used according to their advertised specifications, including frequency range, linear voltage response range, sky coverage range, and standard released software version.
• All parameters are not described in full for each observing mode. For example, total power observing is described generically, not individually per receiver, since the basic process is similar for each receiver.
• Multi-IF modes are not listed specifically, but are straightforward extensions of the other modes listed. See Multi-IF Observing.

3. Observing Modes Summary

• Multi-IF Observing - works with Standard Observing Modes 1-8 above
• Cross Correlation Observing - works with Standard Observing Modes 1-8 above