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Last modified: December 2009

AHELP for CIAO 4.2


Context: proposaltools


Tools that aid in the preparation and submission of Chandra proposals


Below we list tools available to help in feasibility studies, proposal preparation, and proposal submission. Refer to the Proposer area of the Chandra X-ray Center web site for links to these tools and the most current proposing information.

Tools that Access the Chandra Observation Catalog Database

The following are ways to obtain information about observations that have already taken place or have been approved to take place with Chandra.

  • Target Search Form -- for browsing the Chandra Observation Catalog at
  • ChaSeR and Web ChaSeR -- search and retrieval from the Chandra Data Archive; see the Chandra Archive web pages for more information

Tools for Assessing Feasibility

The following tools will aid in determining the feasibility of using one of the Chandra detectors to observe a specific target. When appropriately used, they can help provide a reasonable estimate of exposure time.

  • PIMMS (Portable Interactive Multi-Mission Simulator) -- use when there is an estimate of source flux for a simple source spectra from either a count rate estimated from a previous mission or a flux in some energy band; estimates the amount of ACIS pile-up on the count rate
  • Sherpa or XSPEC -- to provide a simulation of more complicated spectra estimates spectral shape and uncertainty; some pile-up modeling capability
  • MARX (Model of AXAF's Response to X-rays) -- for a source with complicated spatial structure; perform Monte-Carlo simulation of the observation, including approximation to mirror and instrument characteristics; output is a simulated data set that can be analyzed with CIAO and other data analysis packages; simulates ACIS pile-up

Proposal Planning Tools

These tools aid in the preparation of a Chandra proposal, in particular: evaluating target visibility and observing constraints, and converting between date/time systems and coordinate systems. These are available either over the web, or through a command-line interface; refer to ahelp files for the individual tools for more information.

  • COLDEN -- calculate galactic neutral hydrogen column density
  • DATES -- perform interactive calendar and time conversions
  • PRECESS -- perform astronomical coordinate conversions
  • ObsVis -- (command-line interface only) allows inspection of instrument fields-of-view, observatory roll angle and target visibility
  • PRoVis -- (web only) interactively plots Chandra spacecraft pitch, roll and visibility by date for any celestial target

Chandra Proposal Submission

Electronic submission of proposal information is required. The scientific justification must also be submitted electronically. Paper copies will be accepted only from individuals without access to the Internet.

  • WWW version of the Remote Proposal Submission (RPS) system -- a form-based interface to proposal processor; links exist to help for each page of the form and for each parameter; generic RPS help is available at the top of the form. The form is available through the Proposer page URL at the top of this file.
  • E-mail server of the RPS system -- instructions for use may be obtained by sending a blank e-mail message to; note that if you are unable to send a message with no subject or text, enter a single character in either position; the response will be an ASCII file of instructions.

See Also

colden, dates, obsvis, pimms, precess, prop-coords, prop-time

Last modified: December 2009