[fitsbits] Start of the FITS 64-bit Integer "Public Comment Period"

ANNOUNCEMENT: Start of the Public Comment Period on the
FITS 64-bit Integer proposal

This is to announce the official start of the 4-week formal Public Comment
Period on the proposal to add support for 64-bit integers to the FITS data
format.

A detailed description of this proposal is available at
http://fits.gsfc.nasa.gov/fits_64bit.html. This proposal would basically
introduce 3 changes to FITS:

1. Primary arrays or IMAGE extensions containing 64-bit integer
data type images would be designated by BITPIX = 64

2. Columns in FITS binary tables that contain 64-bit integers
would be designated by TFORMn = 'nK'

3. Array descriptor columns in FITS binary tables with 64-bit
integer array length and heap offset values would be designated
by TFORM = '1Qt' (analogous to the existing 32-bit descriptor
type designated by TFORM = '1Pt').

An archive of the previous informal discussions about this proposal is
available at http://listmgr.cv.nrao.edu/pipermail/fitsbits/. In particular,
see the postings in September and October 2001, and in April and May 2005.

All interested members of the FITS community are strongly urged to submit
comments pro or con about this proposal here on the sci.astro.fits
newsgroup, or on the related FITSBITS moderated mail list. Following the
conclusion of this formal comment period, it is likely that the 4 regional
FITS committees and the IAU FITS Working Group will then vote on whether to
formally adopt this proposal.

Finally, it would be particularly useful to the FITS committees to get wider
community input on the 2 issues that were raised in the recent discussions
of this proposal:

1) Is there sufficient reason to support 64-bit integer images in FITS (in
addition to 64-bit integer table columns)?

2) Should the 32-bit P heap pointers be defined as positive signed integers
(with a 2.1 GB maximum heap size) or unsigned integers (with a 4.2 GB
maximum heap size)?.


William Pence
Chairman, IAU FITS Working Group
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__________________________________________________ __________________
Dr. William Pence
NASA/GSFC Code 662 HEASARC +1-301-286-4599 (voice)
Greenbelt MD 20771 +1-301-286-1684 (fax)