Topcat is a popular astronomical tool for manipulating tables of data. It started under the UK Starlink project, was extensively developed under AstroGrid, and now continues to be developed by Mark Taylor in Bristol. You can read about and download Topcat at the official website.

TOPCAT capabilities

TOPCAT can read in tables in a number of formats from various sources, allow you to inspect and manipulate them in various ways, and if you have edited them optionally write them out in the modified state for later use, again in a variety of formats. Here is a summary of its main capabilities:

  • View/edit table data in a scrollable browser
  • View/edit table metadata (parameters)
  • View/edit column metadata (column names, units, UCDs...)
  • Re-order and hide/reveal columns
  • Insert 'synthetic' columns defined by algebraic expression
  • Sort rows on the values in a given column
  • Define row subsets in various ways, including algebraically and graphically
  • Plot columns against each other in 1, 2 and 3 dimensions, distinguishing different subsets
  • Calculate statistics on each column for some or all rows
  • Trigger a configurable action (e.g. object image display) when a column is selected
  • Perform flexible matching of rows in the same or different tables
  • Concatenate the rows of existing tables to create new ones
  • Acquire tables from web services, external filestores or other customisable sources
  • Make single or multiple queries to VO catalogue, image or spectrum services
  • Write modified tables out in original or different format


AstroGrid website is hosted at the Institute for Astronomy, University of Edinburgh  -  last updated: 15-Aug-2012