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IVOA's table access protocol (TAP) provides tabular metadata to astronomers via a standard interface. The TAP service url is: The most common use of the TAP service is within a VO client, such as TOPCAT or pyvo.


  • Download and install the freely available TOPCAT.
  • Start TOPCAT. On most systems this just involves double clicking the topcate JAR file.
  • Select VOTable Access Protocol (TAP) Query from the main menu.
  • Copy and paste or type the following into TAP URL in the Selected TAP Service section
  • Click Use Service
  • You should now be taken to a new window which contains a list of available tables on the left and an ADQL Text box in the lower section.
  • At this point you can type in ADQL queries and click Run Query to execute and return data.
  • Each time you run a query a new entry will appear in another window TOPCAT creates.
  • You can then view the data returned (use the ViewTable Data menu option) or produce plots, etc via the Graphics menu.
  • This is intended to be a quick start guide for using TOPCAT. It is a very powerful tool and you should review TOPCAT's full documentation to get the most out of it.


Code Block
import pyvo as vo

# Connect to the MWA TAP service
mwa_tap_service = vo.dal.TAPService("")

# Execute a simple query
results ="SELECT TOP 3 obs_id, obsname FROM mwa.observation WHERE mode = 'HW_LFILES'")

# Print the results to the console


The MWA ASVO also provide an implementation of the simple cone search protocol. This is a quick search tool which will perform a coordindate search based on an RA, Dec and radius and provide a list of observations which match the criteria.

The cone search url is: 

The most common use of the SCS is within a VO client, such as TOPCAT.