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<p class="MsoNormal"><span style="font-size:11.0pt">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.<o:p></o:p></span></p>
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<p class="MsoNormal" style="line-height:115%"><b><span style="font-family:Helvetica;color:black;mso-ligatures:standardcontextual">William Thompson<o:p></o:p></span></b></p>
<p class="MsoNormal" style="line-height:115%"><b><span style="font-size:9.0pt;line-height:115%;font-family:Helvetica;color:black;mso-ligatures:standardcontextual">Senior Scientist</span></b><span style="font-size:9.0pt;line-height:115%;font-family:Helvetica;color:black;mso-ligatures:standardcontextual"><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:115%"><span style="font-size:9.0pt;line-height:115%;font-family:Helvetica;color:black;mso-ligatures:standardcontextual">ADNET SYSTEMS, Inc.
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<p class="MsoNormal" style="line-height:115%"><span style="font-size:9.0pt;line-height:115%;font-family:Helvetica;color:black;mso-ligatures:standardcontextual">NASA Goddard Space Flight Center, Code 671<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:115%"><span style="font-size:9.0pt;line-height:115%;font-family:Helvetica;color:black;mso-ligatures:standardcontextual">Greenbelt, MD 20771<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:Helvetica;mso-ligatures:standardcontextual"><a href="mailto:William.T.Thompson@nasa.gov"><span style="color:#467886">William.T.Thompson@nasa.gov</span></a>
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<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-family:"Calibri",sans-serif;color:black">From:
</span></b><span style="font-family:"Calibri",sans-serif;color:black">fitsbits <fitsbits-bounces@listmgr.nrao.edu> on behalf of Thomas Robitaille via fitsbits <fitsbits@listmgr.nrao.edu><br>
<b>Reply-To: </b>Thomas Robitaille <thomas.robitaille@gmail.com><br>
<b>Date: </b>Wednesday, July 23, 2025 at 8:40 AM<br>
<b>To: </b>FITSbits <fitsbits@nrao.edu><br>
<b>Subject: </b>[EXTERNAL] [BULK] [fitsbits] 16-bit floats {External}<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in">Hi everyone, <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">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?<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">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.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">I'm curious to hear if this has been discussed before!<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">Thanks,<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">Tom<o:p></o:p></p>
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