Pyfits problem with astrometry.net

[mshemuni]

This error did NOT appear in your code. However it may.
In solve-filed method under AstCalc naturally you're using astrometry.net.
There is a bug in pyfits that may cause a problem in your code.
The error looks like:
TypeError: Cannot cast ufunc add output from dtype('float64') to dtype('uint16') with casting rule 'same_kind'
The error did happen to a certain type of fits file. I was able to solve a field for files came from different sources. But in one of my sources the error occurred.
According to this answer you need to use an older version of pyfits or basically use "--no-fits2fits" flag in astrometry.net's solve-field.