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I am perhaps the person with the longest exposure to FITS. I expect that adding 16-bit floats would do little harm. But I have not seen a proper exposition of why it is needed. And I have 50+ years of writing radio astronomy software. At this stage I would
vote against it until a proper set of examples are described.</div>
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Eric Greisen</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> fitsbits <fitsbits-bounces@listmgr.nrao.edu> on behalf of William Pence via fitsbits <fitsbits@listmgr.nrao.edu><br>
<b>Sent:</b> Saturday, July 26, 2025 1:11 PM<br>
<b>To:</b> Fitsbits <fitsbits@listmgr.nrao.edu><br>
<b>Subject:</b> Re: [fitsbits] [EXT] Re: 16-bit floats {External} {External}</font>
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<div class="PlainText">[Have had technical difficulties posting here; here’s another attempt.]<br>
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Based on the discussion so far I am inclined to support adding the 16-bit floating point format to FITS, but not the 128-bit format, as a fundamental datatype in images and binary table columns. As a reminder, the numerical range of the float16 datatype is
limited to +65504 to -65504 and the precision is limited to about 4 decimal digits. That means the largest values (in the range of about 32000 to 65500) are only precise to +/- 32, i.e. the largest possible value is 65504 and the next smaller allowed values
are 65472, 65440 and so on. Based on my own experience in optical and Xray astronomy I can’t think of many applications (or any in fact) where this float16 datatype would be appropriate to use. Apparently it could be useful for some radio astronomy data
however. <br>
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Bill<br>
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