Leicester Database and Archive Service
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Downtime expected shortly as all LEDAS services are moved to a new server.

Leicester Database and Archive Service Overview

High-energy Data:

LEDAS provides an on-line astronomical database and archive access service biased towards data from high energy astrophysics missions. Our three main datasets are as follows:
  • The UK ASCA Public Data Archive was released in November 1998. It provides access to ASCA images and data files and is a mirror of the ASCA archive held by HEASARC at GSFC, in the USA. Data from this on-going mission is ingested into the database as soon as it is received from HEASARC.

  • ROSAT was the most successful X-ray astronomy mission to date, completing nearly a decade of successful in-orbit operations. The UK ROSAT Public Data Archive contains all public data from the X-ray telescope obtained during the pointed observation phase of the mission. LEDAS also archives and provides access to Wide Field Camera data from the All-sky Survey and pointed phases of the mission.

  • The Ginga Data Products Archive was conceived and created by the Ginga support staff at Leicester. Users of the Ginga archive can obtain reduced, quality controlled data products (data cubes, light curves and spectra), thereby making Ginga data more accessible to the typical astronomer. The archive was completed and released in January 1998.
In addition to these, LEDAS also provides access to hundreds of other astronomical catalogues from ground-based observations and other space missions.

Accessing the archives:

The database collection can be accessed via the Web using the ARchive Network InterfacE (ARNIE).

The Digitized Sky Survey:

Since 1998 LEDAS has offered an optical sky image creation service, the Digitized Sky Survey (DSS) Image Browser. The DSS browser is an online digitised version of Schmidt survey plates covering the entire sky at 1.7" resolution. The LEDAS DSS service offers access to the full sky, and users are able to request images up to 1.8 degrees square in FITS, HDS and GIF formats. Thre is also a batch request service available which allows up to 15 images to be requested at once.


To help UK astronomers avoid the potentially awkward and time-consuming process of downloading X-ray data analysis software packages from the USA, LEDAS maintains a web mirror of several commonly used software packages.

  • Chandra data analysis software
  • Ginga data analysis software
  • HEASoft is a comprehensive suite of programs covering many aspects of X-ray data analysis, including imaging, spectral modelling and timing analysis.
  • FTOOLS is a collection of utility programs used extensively in X-ray astronomy to create, examine, or modify the contents of FITS data files.
  • PIMMS is a popular tool for simulating count rates from most X-ray missions, based on count rates and assumed spectra from other missions.