Rules for the Registry of FITS Conventions

Maintained by the IAU FITS Working Group

Last Revised: 23 June 2006

1. Purpose

The IAU FITS Working Group has established the Registry of FITS Conventions to provide a central and authoritative repository for documenting conventions that have been developed by the FITS user community for storing and transmitting various types of information in FITS format data files. A FITS convention is defined as a set of related FITS header keywords, and optionally, other data structures within FITS tables or FITS images, that are to be used for a specific purpose. Because it is often inappropriate or impractical to document these conventions in the FITS Standard itself, the Registry provides an alternative process for documenting conventions for the benefit of future FITS users.

2. Convention Requirements

To be included in the Registry, a convention should meet the following requirements:

• The convention should conform to the FITS format requirements as defined in the latest version of the IAU-FWG approved documents that make up the official FITS Standard. Exceptions may be made for conventions that violate the current FITS Standard as long as this fact is clearly stated in the documentation about the convention, and if there is a good justification for doing so (e.g., the convention conformed to the the Standard at the time it was developed, or the convention serves an important specialized purpose, etc.).

• The convention should be in actual use in current or previously generated publicly available FITS data files. Generally speaking, proposed new FITS conventions that are not yet in actual use should not be submitted to the Registry until the proposal is fairly mature and has demonstrable support from at least a significant subset of the FITS user community.

• The submitted documents (see below) should clearly describe the convention and should concisely define how any keywords and any other FITS data structures are to be used.

3. Submittal Process

Before submitting a FITS convention for inclusion in the Registry, the following items should be prepared:

1. A text document describing the convention. The following guide lines should be followed when preparing this document:
   • Include a short descriptive title that can be used to refer to this particular convention.
   • Provide the names of the persons or organizations responsible for developing this convention.
   • Show the date that this particular version of the descriptive document was written or last modified.
   • The main body of the document should provide a complete description of the purpose and implementation of the convention. It may contain URLs or references to other papers that provide additional background material or supplemental technical information that is not essential for a basic understanding of the convention.
   • Mention the approximate date that this convention was first used in actual FITS files.
   • Provide a list of at least some of the FITS data sets that have used the convention.

   This document should be written in English and provided in one or more of the following formats: plain ASCII text, postscript, PDF, and/or Microsoft Word. Any other source documents and ancillary files that are needed to edit or reformat the document should also be provided.

2. A simple plain text file that includes a one-paragraph description of the convention and a short definition of every keyword that is used in the convention that would be suitable for inclusion in a FITS keyword dictionary. This text may be entered on the Registry Web site to provide a short description of the convention.

3. One or more sample FITS files that use the convention, preferably smaller than a few megabytes in size.

4. While not strictly required, a XML format document that formally defines the convention would also be useful. Services that rely on the XML definitions may be established in the future. Contact the maintainers of the Registry for further guidelines on preparing this XML document.

Any questions regarding the preparation of this material should be sent to the Registry maintainers, in care of the FITS Support Office at fits@fits.gsfc.nasa.gov. Once the material is ready to be submitted, send a message to the above email address, and you will then be contacted with further instructions on how to submit the material.

4. Public Comment Period Process

The public comment period is designed to advertise the existence of the convention to the wider FITS user community and to ensure that the submitted material is as complete and accurate as possible.

1. Once the documentation and sample FITS files have been submitted, the Registry maintainers (i.e., one or more designated members of the IAU-FWG) will make the material available in the "Under Review" section of the Registry of FITS Conventions, which is currently maintained on the FITS Support Office web site.

2. The Registry maintainers will send a notification message to the FITSBITS mail exploder announcing the start of an approximately 4 week public comment period that provides an opportunity for members of the FITS user community to review and comment on the submitted material. The main focus of the review should be on whether or not the documentation is clear and complete. Comments about the implementation of the convention are also welcome, but because many of the conventions are already in widespread use, it may not be feasible to make any changes to how the convention is implemented.

3. At the end of the public comment period, the submitters will be given an opportunity to make any appropriate modifications to the material in response to the public comments and re-submit it for inclusion in the Registry. If major changes are made, then it may be desirable to submit the revised material for another round of public comments. (The IAU FWG Executive Committee will decide if there is any doubt about whether this is required).

5. Approval Process

After the public comment period, in most cases the documentation about the convention will be moved from the "Under Review" section of the Registry to the main section of the Registry without undergoing any further formal review or approval. The IAU-FWG reserves the right, however, to request further changes to the submitted material before the convention will be listed in the Registry (for example, if the submitted material is felt to be incomplete or inaccurate).

In practice, the Registry maintainers will notify the members of the IAU-FWG by email whenever a convention has completed the public comment process and is ready to be moved from the "Under Review" section to the main section of the Registry. At this point, any IAU-FWG member may raise objections and request a formal vote on whether the convention should be added to the Registry. In this case, the IAU-FWG chairman will call for a discussion and vote on the matter. A simple majority of the voting members must approve the convention for it to be added to the Registry. If the convention is not approved, then the submitters will be notified why the convention was rejected, along with suggestions, if possible, on what changes should be made before submitting the convention for reconsideration.

Once the convention has been approved, either by a formal vote, or if no IAU-FWG member raises any objections within 3 weeks of the notification email from the Registry maintainer, then the documentation about the convention and the sample FITS file(s) will be added to the Registry.

The original submitters, or any other interested persons, may submit updates or revisions to the documents that describe the convention at any time. It will be up to the IAU-FWG to decide whether the revised material may be added to the repository immediately, or whether it first should go through the full public comment and approval process as described above.