FITS header

A public interface to the FITS header archive has been developed. Access is given to FITS information of images older than 1 year (the propriety period):

http://www.not.iac.es/observing/forms/fitsarchive/

This interface will be further developed and improved.

Given the need to be able to automatically process images it should be possible to uniquely define the type of observation (imaging, spectroscopy, calibration, test, etc) from the FITS keywords. Our current set of observing description keywords do not follow any specific system and in general the post-processing and analysis tools we use rely mostly on specific instrument keywords (e.g, if there is a slit in the light path) to determine the type of observation. Of course we can invent our own system, but that requires that we should carefully consider how to do this ourselves. On the other hand, it would make things more difficult if we change the name of the existing keywords. It was considered that the system of ESO using 3 different keywords to define observations giving the category (science, calib, test, etc), the type (object, std, sky, flat, lamp, etc) and (observing) technique (image, spectrum, echelle, polarimetry, etc) where each of them can have more than one entry separated by commas is well defined and should cover all possible observations. The keyword naming used by ESO is rather cumbersome and also to be in some sense backward compatible it was agree to use our existing keywords (OBS_TYPE for `category' and IMAGETYPE for `type') and add a third keyword (name to be defined) to describe the observing technique used and provide a full description using the parameters as defined by ESO. In this way all our data will be automatically ``Virtual Observatory'' compatible in this respect as well and adapting to any reduction packages which can process ESO data should be relatively easy.

Thomas Augusteijn 2009-05-14