TOPCAT: A powerful Tool for OPerations on Catalogues And Tables

This session forms part of the astronomy strand of the residential module DISC6001 along with the session Introduction to Astronomy Data Manipulation and Visualisation and will be led by Daniel Asmus.

Aims & Objectives

During this session we will learn about a powerful Tool for OPerations on Catalogues And Tables (TOPCAT), which was specifically designed for efficient manipulation and processing of tables in astronomy with emphasis on inter-connectivity with online data services and tools in particular in the Virtual Observatory world. The goal of this session is to be able to use TOPCAT and its key functionalities effectively afterwards.


After a motivational introduction, most of the session will be structured in an interactive way including hands-on exercises. Specifically, the following subjects will be covered:

  • Basic table operations like loading, viewing, editing and saving

  • Basic extraction of information from tables: statistics and visualization

  • Table operations: subsets, concatenating, matching

  • VO queries and cone searches

  • Communication with other tools like Aladin

Finally, a number of advanced problems for supervised self study are provided. The structure will roughly be:

  • Introduction Presentation

  • Interactive Exercises Part 1 (basics)

  • Break

  • Common Operations Presentation

  • Interactive Exercises Part 2 (commons)

  • Presentation for advanced Problems

  • Supervised self-Study of advanced problems (alone or in groups)


- Software homepage:

- Documentation:

- Demo Video:

- The Virtual Observatory:


- Gallery:

- Tutorial script:

Prerequisites (recommended)

- Installation of TOPCAT:

- Installation of Aladin

- Basic knowledge about astronomical tables and common astrophysical properties like coordinates, spectrum, fluxes and magnitudes

- Basic knowledge about astronomical databases

- Basic knowledge the Virtual observatory

Approximate number of hours

- Presentations: 1h

- Interactive exercises: 1- 1.5h

- Self-Study: 1h