6. Issues and Limitations

6.1. Memory Issues

Some primitives use a lot of RAM memory and they can cause a crash. Memory management in Python is notoriously difficult. The DRAGONS’s team is constantly trying to improve memory management within astrodata and the DRAGONS recipes and primitives. If an “Out of memory” crash happens to you, if possible for your observation sequence, try to run the pipeline on fewer images at the time, like for each dither pattern sequence separately.

Then to align and stack the pieces, run the alignAndStack recipe:

$ reduce @list_of_stacks -r alignAndStack

6.2. Emission from PWFS2 guide probe

The PWFS2 guide probe leaves a signature on imaging data that cannot be removed. Ideally, one would be using the OIWFS, the On-Instrument Wave Front Sensor, but there has been issues with it. See https://www.gemini.edu/sciops/instruments/flamingos2/status-and-availability for the current status of the instrument. The effect of the PWFS2 guide probe will in many cases compromise photometry in the region affected.

6.3. Double messaging issue

If you run Reduce without setting up a logger, you will notice that the output messages appear twice. To prevent this behaviour set up a logger. This will send one of the output stream to a file, keeping the other on the screen. We recommend using the DRAGONS logger located in the gempy.utils.logutils module and its config() function:

from gempy.utils import logutils
logutils.config(file_name='f2_data_reduction.log')