iraf.net

Running iraf 2.16.1-2018.11.01 on a linux64 machine.

Desire: Reducing data from a Fiber Spectrograph

Step 1) apsum from apextract pkg is run on a flat-field image. This image is designed to permit the determination of the location and shape of each fiber (aka aperture). Using apsum, all fibers were found and traced. Aperture profile information stored in a database.

Step 2) Attempt was made, multiple times, to use that information obtained in 1) to extract apertures from an object image. The reference image is the one processed in step 1). Unhappily, that task fails immediately, with the error ?Bad aperture list.? The option in apsum ?Find Apertures?? is NO as is the Trace Apertures? Option. Both the location and shape of each fiber spectrum (aperture) should be very well determined from the information provided in 1). (The error appears just after the msg ?June 19:22:10: Database ? 72 apertures read for txs3917 from APDB?). That image txs3917 was the one processed in step 1).

In an attempt to overcome that error in step 2), the image header for the object was populated with SLFIB01...SLFIB02, etc. Already present in the header were the APNUM from an earlier epoch. Some other earlier data, reduced eons ago, also had in the image header APID?s listed in addition to the APNUMs. The use of the SLFIB? was determined from the information provided by the apall help pages (in the Default Aperture Parameters section: apidtable.)

In a previous era, I was able to obtain to reduce the data, as desired, as outlined in step 2), using images obtained with the same fiber spectrograph.

Thus, I am assuming that the image header entry requirements seem to have changed from those of earlier iraf versions. I have yet to determine exactly what it takes to satisfy the task, or to overcome this ?Bad Aperture list? error. Nor have I been able to find any relevant comment on searching the web.

Any suggestion would be most appreciated. Data can be provided to help clarify the situation.

Regards!
ddh

Hello DDH,

Please post or send me (frank.valdes@noirlab.edu) the parameter setttings. A good way to do this is to use . It might also help to see the database file where the aperture ids are defined.

Frank Valdes