about Grigoris Maravelias
Month: <span>November 2011</span>

Month: November 2011

IRAF’s error message 502 and pixel value replacement

While running a data reduction of IR observations with IRAF, the ccdproc printed this error: ERROR (502, “floating point invalid operation”) which means that some values of the image used (the flat image in this case) are not suitable for the performing mathematical actions (like division with 0s). Moreover the …

Buggy behaviour of unpack within numpy.loadtxt

The routine loadtxt from numpy (numpy.loadtxt) can be used to load columns of data from various files. This works great as long as numbers exist and becomes buggy with strings. Suppose we have a file (named ‘test.test’) with these values: 3103725. 1616.93596535 13.656 0 2011-05-23T23:49:35 3139474. 1405.95436047 13.643 0 2011-05-23T23:51:16 …