Chandra X-Ray Observatory

CDA - Home

Data Analysis Links
CDA Status
  • The archive is fully functional.
Reprocessing Status
    Reprocessing IV has been completed in December 2014.
Current Software Releases
  • ASCDSVER: 10.12.6
  • CALDBVER: 4.11.1
  • Electrical Outage 11/05/21 - 11/06/21
    There will be a planned electrical outage Friday, November 5 2021, 5:30PM - Saturday, November 6 2021, 6:00PM EDT. During this time period ChaSeR and other archive interfaces will be unavailable.
  • Electrical Outage on 07/28/21
    There will be a planned electrical outage Wednesday, July 28 2021, 8:00PM - 10:00PM EDT. During this time period ChaSeR and other archive interfaces will be unavailable.
  • Downtime on 6/12/21
    Due to electrical work, the public interfaces of the Chandra Data Archive will not be available on Saturday 6/12 from 4 AM to 9 PM.
  • Repro V Begins
    The fifth major reprocessing of the archive (Repro V) has started! Details can be found here.
  • Past Notices
Welcome to the Chandra Data Archive

The Chandra Data Archive (CDA) plays a central role in the operation of the Chandra X-ray Center (CXC) by providing support to the astronomical community in accessing Chandra data. The CDA offers access to digital archives through powerful query engines, including VO-compliant interfaces and also serves as a permanent storage repository of contributed data products by authors who have processed images or other pertinent and valuable datasets that are essential to their publications.

Access the Chandra Data Archive

  • ChaSeR: Search & Retrieval interface for scientists, allowing specification of detailed selection criteria. Chandra Fast Image is a simplified quick search tool for Chandra X-ray images and other data for the general public.
  • HTTPS: Direct access to the primary and secondary data products for all observations that are publicly released.
  • Cool Chandra Targets (formerly known as CATs): the list of approved Cool Chandra Targets (CCTs) programs, including the PI names, titles and abstracts.
  • Footprint Service: A search by position or object name overlays the footprints of Chandra Observations on Digital Sky Survey images, allowing further selection and retrieval of observations.
  • Chandra MOCs: Multi-Order Coverage maps (MOCs) for public Chandra observations, that can be used to visualize and analyze the global Chandra footprint.
  • Chandra Source Catalog: The most comprehensive catalog of sources detected in public Chandra Observations. The catalog can be accessed through CSCview.
  • CIAO Tools: There are command-line scripts for finding and downloading publicly-available Chandra data from the Archive. Please note that proprietary data can only be accessed using ChaSeR.
    • find_chandra_obsid: The tool will find publicly available Chandra data that covers a circular region of sky (a point search can be used by setting the search radius to 0).
    • download_chandra_obsid: The tool will download public data by ObsId from the Chandra archive.
  • Bibliography Search: Simultaneous browsing of the archive and the literature with a large repertoire of selection criteria.
  • Processing Status: Information on the processing status of Chandra observations.
  • Special Requests: Requests for services not available through standard interfaces such as requesting a custom dataset identifier; requesting a custom database query; and many others.
  • ZTF Annotation: Annotation of the Chandra archival observations with Zwicky Transient Factory objects
  • CDA Data Object Identifiers (DOIs): The new way to cite Chandra data in publications!

This page maintained by the Chandra Data Archive (

Last modified: 2024-02-05

Smithsonian Institute Smithsonian Institute

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email: Smithsonian Institution, Copyright © 1998-2024. All rights reserved.