[fitsbits] [EXT] Re: 16-bit floats {External} {External}

[William Pence]

[Have had technical difficulties posting here; here’s another attempt.]

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. 

Bill