[fitsbits] [EXTERNAL] [BULK] 16-bit floats {External}

[Thompson, William T. (GSFC-671.0)[ADNET SYSTEMS INC]]

My main concern is that not all software environments, such as IDL, will support 16-bit or 128-bit floats.  The main purpose of FITS is portability.

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[signature_868686802]

William Thompson
Senior Scientist
ADNET SYSTEMS, Inc.
NASA Goddard Space Flight Center, Code 671
Greenbelt, MD 20771
o: 301.286.2040
William.T.Thompson at nasa.gov<mailto:William.T.Thompson at nasa.gov>


From: fitsbits <fitsbits-bounces at listmgr.nrao.edu> on behalf of Thomas Robitaille via fitsbits <fitsbits at listmgr.nrao.edu>
Reply-To: Thomas Robitaille <thomas.robitaille at gmail.com>
Date: Wednesday, July 23, 2025 at 8:40 AM
To: FITSbits <fitsbits at nrao.edu>
Subject: [EXTERNAL] [BULK] [fitsbits] 16-bit floats {External}

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Hi everyone,

As far as I understand, IEEE 754-2008 standardized the representation of 16-bit floats (as well as 128-bit floats). I was curious whether there is any interest in extending the FITS format to allow BITPIX=-16 and BITPIX=-128?

I am aware of some modern projects that would benefit from having 16-bit floats, since they consider it to be sufficient in precision to store very large datasets, and using 16-bit floats would perform a lot better than using compression on 32-bit floats for example, and 16-bit floats would allow a larger dynamic range than using 16-bit ints with BSCALE/BZERO.

I'm curious to hear if this has been discussed before!

Thanks,
Tom
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