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IPHAS Data Release 2

This repository contains the source code that was used to uniformly calibrate and compile the source catalogue for the Second Data Release of the INT/WFC Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS DR2).

The principal task of this code is to take the raw set of IPHAS source detection tables, which are kindly provided by the Cambridge Astronomical Survey Unit (CASU), and transform them into a globally calibrated source catalogue, which details the best measurement of each unique source in a user-friendly format.

More information about the project can be found at


  • the master script used to create the data release.
  • paper/: the accompanying paper describing the generated catalogue.
  • dr2/: the Python package that is used by to create the data release, in particular the source catalogue. It consists of several modules:
    • dr2.detections: module used to convert the detection tables generated by the CASU pipeline into tables with user-friendly columns, broadly following the WSA/UKIDSS conventions.
    • dr2.bandmerging: modules used to merge r/i/Halpha detection tables into band-merged field catalogues.
    • dr2.offsets: computes the magnitude shifts between exposure overlaps.
    • dr2.calibration: computes a global photometric calibration from the data provided by
    • dr2.seaming: identifies multiple detections of the same object and identifies the best (primary) detection for each unique source.
    • dr2.concatenating: concatenates the output of the seaming module into the final source catalogue.
    • dr2.images: creates a release of the pipeline-processed images with update headers to reflect the IPHAS DR2 uniform calibration.
  • scripts/: various helper scripts, including:
    • postgresql/: script to ingest the DR2 catalogue into a PostgreSQL db.
    • sqlite/: script to ingest the DR2 catalogue into an SQLite db.


The script in the root directory contains all instructions necessary to produce the IPHAS DR2 source catalogue. It depends on the IPython.Parallel package and several modules from the included dr2 package to generate the data release in parallel on a computing cluster.


IPHAS DR2 was generated using

  • Python 2.7.6
  • Astropy 0.3
  • Numpy 1.7.1
  • Scipy 0.12.0
  • IPython 0.13.2


The source code is released under the MIT license, see the LICENSE file.