ISIS to .dat o.fit

[Andrew Smith]

I have converted some CALSPEC spectrophotometry standatds to .dat as they are in Fits table format.

I have tried converting to normal fits using the ISIS-> profile -> save function and saving as .fit However I find there seems to be an error in the conversion. See the comparison.

ISIS Dat to Fit.png (44.46 KiB) Viewed 3743 times

Here is an image of the start of the .dat file

ISIS Dat to Fit1.png (27.1 KiB) Viewed 3743 times

I think the issue is that ISIS is assuming a constant increment looking at the full .dat file the increment varies.

Regards Andrew

[David Boyd]

Hello Andrew,

When I converted the NGSL files from FITS table format I had the same problem. I defined a regular wavelength spacing and quadratic interpolated the original flux grid onto that using interp1d to produce the simple FITS file version.

David