Thanks Niall,
Yes I've tried the verification tool with the following result:
fitsverify 4.14 (CFITSIO V3.002)
--------------------------------
1 Header-Data Units in this file.
=================== HDU 1: Primary Array ===================
*** Error: Keyword #16, TEMP: String contains non-text characters.
*** Error: Keyword #13, DATE-OBS: "" is not a string.
*** Error: Keyword #13, DATE-OBS: (from CFITSIO error stack:)
input date string has illegal format:
*** Error: checking data fill: tried to move past end of file
1 | SIMPLE = T
2 | BITPIX = 16
3 | NAXIS = 2
4 | NAXIS1 = 1392
5 | NAXIS2 = 1024
6 | BZERO = 32768
7 | BSCALE = 1
8 | CAMERA ='QHY2Pro Camera'
9 | EXPTIME = 600.0000
10 | GAIN ='60%'
11 | OFFSET = 119
12 | TIMESYS ='UTC'
13 | DATE-OBS='2009-03-21T00:06:39.515'
14 | PIXXSIZE= 6.50
15 | PIXYSIZE= 6.50
16 | TEMP ='-15.3°C'
17 | END
17 header keywords
16-bit integer pixels, 2 axes (1392 x 1024),
++++++++++++++++++++++ Error Summary ++++++++++++++++++++++
HDU# Name (version) Type Warnings Errors
1 Primary Array 0 4
**** Verification found 0 warning(s) and 4 error(s). ****
Obviously there are errors according to this tool, but I have to say that deep sky stacker has no problems reading the same file. I will raise the problem in the QHY forum. Any other suggestion is welcome.
Many thanks !. JLuis.