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Hi all! I have Halpha and R imaging (obtained with the ESO/WFI) and I want to flux calibrate the sources we have identified. For these we have a series of exposures for spectrophotometric standards. As far as the Halpha standards I know that I have to convolve the standard spectrum with the response of the filter.

I saw that sbands is the function to perform this action. I imagined that I can provide the standard spectrum from the library of onedstds along with a text file for the bandpass. So far though I cannot understand how to call the standard spectrum. I tried to use it as onedstds$oke1990/eg71.dat and various other alterations of this (including the full path to the file), but every try fails.

I noticed that sbands asks for an image, while the standards are given as .dat files, in which case if sbands is expecting a fits image then it is going to fail every time.

So, is there a way to call a standard spectrum?Or I should use another application for this proccess?

Best
Grigoris

Hi again!

Finally, I tried to convert a standard .dat file into a fits image (with rspectext) and it worked.
Is there a way to apply a filter response ? If not then is there any suggestion for an application to use?

Thanks!
Grigoris

Hi! Obviously I was too tired yesterday, since then answer to my question was in front of my eyes but couldn't see it. You can simply add the filter transmission file in the bandpass file!

To sum up:
1. rspectext to transform a standard .dat file to .fits image.
2. sbands using the produced image (of 1-D spectrum) of standard and a bandpass file, which contains the bandpasses (names, central wavelengths, widths, filter transmission files).

Cheers!

Grigoris