8. PAPI FAQ

8.1. Installation

8.1.1. Does PAPI work with python 3?

It has not been tested yet, but probably it does not work.

8.1.2. What GUI toolkit does PAPI-QL use?

PAPI Quick-Look uses Qt toolkit.

8.1.3. Can PAPI-QL work with PyQt5?

It has not been tested yet, but probably it does not work.

8.2. Data reduction

8.2.1. What is the best way to reduce PAPI data?

The recommend to use the OT and execute the OBs. That way the headers will include meta-data about the observation, and thus the pipeline can group the data and find the required calibrations for a successful reduction. Then, you only have to type:

> papi -s /data1/PANIC/my_program/

8.2.2. How can process a broken, interrupted or non OT sequence ?

PAPI is prepared to work with complete data sequences taken with the OT. Sequences are defined mainly by the PAT_EXPN, PAT_NEXP keywords:

  • PAT_EXPN: Seq. exposition number (1 to N)
  • PAT_NEXP: Total number of expositions (N) of the sequence

In case you need to process a broken, interrupted or sequence not taken using the OT, you can build a PAPI compliant sequence using one of the next options:

  • the Quick-Look option in the pop-up menu (FITS->Create DataSeq) over a set of seletect files on the list view.
  • the createDataSeq command line tool, as follow:

Example:

$createDataSeq -s /tmp/my_files.txt -t SKY_FLAT -o /mydata

8.2.3. How does PAPI treat bad pixels ?

See Bad Pixel Treatment.

8.2.4. How can we reach hundredth of magnitude accuracy in photometry ?

The best way to accurately photometrically calibrate PANIC images is to use 2MASS stars in the field itself to derive the photometric solution. The accuracy strongly depends on the number of bright 2MASS stars within the filed of view, but ranges from a few 1/100th of a magnitude to 0.1 magnitudes if only faint stars are contained in the field. Additionally, observing supplementary standard star fields can be asked for when preparing the observations. To perform the 2MASS photometric calibration on an image you should use the ‘photometry’ command as follow:

> photometry -i /directory/prereducedField.fits -o test.pdf

8.2.5. How good is PAPI astrometry and how are PSF variations corrected ?

At present the pipeline applies a correction for PSF distortions based on a distortion map derived during the astrometric calibration done with SCAMP (a software developped by Emmanuel Bertin) and 2MASS.