Actuator (pyoof.actuator
)¶
Introduction¶
This is a developer sub-package. The purpose of actuator
is to provide tools for telescopes that have included in their structure an active surface control system. An active system has a model to correct for gravitational deformations, what we propose here is to use the results from fit_zpoly
(out-of-focus holography) to compute such model and return the required corrections to apply to every actuator in the active surface, and hence improve the telescope’s sensitivity.
The current sub-package only contains corrections for the Effelsberg telescope in the class EffelsbergActuator
, future versions will expand this to other types of active surface.
Active surface at the Effelsberg telescope¶
To use the actuator
is simple, first let’s take a look at the active surface control system and its look-up table at the Effelsberg telescope.
import matplotlib.pyplot as plt
from astropy import units as u
from pyoof.actuator import EffelsbergActuator
ae = EffelsbergActuator(
frequency=34.75 * u.GHz, # obs frequency
nrot=1, # convention parameter
sign=-1, # convention parameter
order=5, # Polynomial order
sr=3.25 * u.m, # Sub-reflector radius
pr=50 * u.m, # Primary reflector radius
resolution=1000 # Phase-error map resolution
)
fig = ae.plot()
plt.show()
(Source code, png, hires.png, pdf)
The following table is the transformation from the actuator space (in micrometer displacement) to the phase-error space. Notice that nrot
and sign
are important parameters to be defined. Several tests at the Effelsberg telescope lead us to find those values.
Reference/API¶
pyoof.actuator Package¶
This sub-package contains tools to transform the telescope phase (as an optical system) to an equivalent phase in terms of an active surface control system that can correct such deformations using actuator displacement.
Classes¶
|
Several tasks for the Effelsberg telescope and the active surface control system located in the 6.5 m sub-reflector. |