Test ADC wheel

This notebook demonstrates how to use the various atmospheric dispersion correctors in METIS. Note that the action of an adc is currently restricted to a transmission loss. The implementation of the geometric differential refraction residuals will follow at a later stage.

import scopesim as sim
sim.bug_report()

# Edit this path if you have a custom install directory, otherwise comment it out.
sim.rc.__config__["!SIM.file.local_packages_path"] = "../../../../"

import numpy as np
from matplotlib import pyplot as plt
%matplotlib inline

If you haven’t got the instrument packages yet, uncomment the following cell

# sim.download_packages(["METIS", "ELT", "Armazones"])

cmd = sim.UserCommands(use_instrument="METIS", set_modes=['img_lm'])

The ADC to use is defined by "!OBS.adc". This can be set to false when no ADC is in the path. The default for LM band imaging is

cmd["!OBS.adc"]

src = sim.source.source_templates.empty_sky()

metis = sim.OpticalTrain(cmd)

The effect metis['adc_wheel'] works the same way as e.g. metis['filter_wheel']. The following ADCs are now available (yes, there’s only one) and can be selected with metis['adc_wheel'].change_adc() as demonstrated below.

metis['adc_wheel'].adcs

Run a simulation with the ADC in the path:

metis.observe(src, update=True)
implane_adc = metis.image_planes[0].data

Now remove the ADC from the path by changing to False. Run the simulation without the ADC:

metis['adc_wheel'].change_adc(False)

metis.observe(src, update=True)
implane_no_adc = metis.image_planes[0].data

Compare the image plane simulated with and without the ADC. The ratio should be equal to the throughput of the ADC (90 per cent):

med_adc = np.median(implane_adc)
med_no_adc = np.median(implane_no_adc)
print("With ADC:    {:.1f}".format(np.median(med_adc)))
print("Without ADC: {:.1f}".format(np.median(med_no_adc)))
print("Ratio:       {:.1f}".format(med_adc/med_no_adc))