Channel#
- class aiapy.response.Channel(channel: Unit('Angstrom'), instrument_file=None)[source]#
Bases:
object
Interface to AIA channel properties and response functions.
This class provides an interface to the AIA channels and methods for calculating the effective area and wavelength response functions as a function of wavelength.
- Parameters:
Examples
>>> import astropy.units as u >>> from aiapy.response import Channel >>> c = Channel(171*u.angstrom) >>> c.telescope_number 3 >>> c.name '171' >>> c.channel <Quantity 171. Angstrom>
Attributes Summary
Nominal wavelength at which the bandpass of the channel is centered.
Contamination of effective area from crosstalk between channels.
Uncorrected effective area as a function of wavelength.
Gain of the CCD camera system.
Returns True for UV and visible channels 1600, 1700, 4500 Å.
Label denoting the telescope to which the given channel is assigned.
Array of wavelengths over which channel properties are calculated.
Methods Summary
eve_correction
(obstime, **kwargs)Correct effective area to give good agreement with full-disk EVE data.
wavelength_response
([obstime, ...])The wavelength response function is the product of the gain and the effective area.
Attributes Documentation
- channel#
Nominal wavelength at which the bandpass of the channel is centered.
- contamination#
- crosstalk#
Contamination of effective area from crosstalk between channels.
On telescopes 1, 3, and 4, both channels are always illuminated. This can lead to contamination in a channel from the channel with which it shares a telescope. This impacts the 94 and 304 Å channels as well as 131 and 335 Å. See Section 2.2.1 of [1] for more details.
References
- effective_area#
Uncorrected effective area as a function of wavelength.
According to Section 2 of [boerner], the effective area is given by,
\[A_{eff}(\lambda) = A_{geo}R_P(\lambda)R_S(\lambda)T_E(\lambda)T_F(\lambda)D(\lambda)Q(\lambda),\]where,
\(A_{geo}\): geometrical collecting area
\(R_P\), \(R_S\): reflectances of primary and secondary mirrors, respectively
\(T_E\), \(T_F\): transmission efficiency of the entrance and focal-plane filters, respectively
\(D\): contaminant transmittance of optics
\(Q\): quantum efficiency of the CCD
The effective area contains information about the efficiency of the telescope optics and its sensitivity as a function of wavelength. All of the telescope properties are read from the AIA instrument files available in SolarSoft.
References
- entrance_filter_efficiency#
- focal_plane_filter_efficiency#
- gain#
Gain of the CCD camera system.
According to Section 2 of [boerner1], the gain of the CCD-camera system, in DN per photon, is given by,
\[G(\lambda) = \frac{hc}{\lambda}\frac{g}{a}\]where \(g\) is the camera gain in DN per electron and \(\approx 3.65\) eV per electron is a conversion factor.
References
- geometrical_collecting_area#
- is_fuv#
Returns True for UV and visible channels 1600, 1700, 4500 Å.
- name#
- plate_scale#
- primary_reflectance#
- quantum_efficiency#
- secondary_reflectance#
- telescope_number#
Label denoting the telescope to which the given channel is assigned.
See
crosstalk
for context of why this is important.
- wavelength#
Array of wavelengths over which channel properties are calculated.
Methods Documentation
- eve_correction(obstime, **kwargs)[source]#
Correct effective area to give good agreement with full-disk EVE data.
The EVE correction factor is given by,
\[\frac{A_{eff}(\lambda_n,t_0)}{A_{eff}(\lambda_E,t_e)}\]where \(A_{eff}(\lambda_n,t_0)\) is the effective area at the nominal wavelength of the channel (\(\lambda_n\)) at the first calibration epoch and \(A_{eff}(\lambda_E,t_e)\) is the effective area at the
obstime
calibration epoch interpolated to the effective wavelength (\(\lambda_E\)).Note
This function is adapted directly from the aia_bp_corrections.pro routine in SolarSoft.
- Parameters:
obstime (
Time
) – The time of the observation.correction_table (
Table
orstr
, optional) – Table of correction parameters or path to correction table file. If not specified, it will be queried from JSOC. If you are calling this function repeatedly, it is recommended to read the correction table once and pass it with this argument to avoid multiple redundant network calls.calibration_version (
int
, optional) – The version of the calibration to use when calculating the degradation. By default, this is the most recent version available from JSOC. If you are using a specific calibration response file, you may need to specify this according to the version in that file.
- Return type:
- wavelength_response(obstime=None, include_eve_correction=False, include_crosstalk=True, **kwargs)[source]#
The wavelength response function is the product of the gain and the effective area.
The wavelength response as a function of time and wavelength is given by,
\[R(\lambda,t) = (A_{eff}(\lambda) + A_{cross}(\lambda))G(\lambda)C_T(t)C_E(t)\]where,
\(A_{eff}(\lambda)\) is the effective area as a function of wavelength
\(A_{cross}(\lambda)\) is the effective area of the crosstalk channel
\(G(\lambda)\) is the gain of the telescope
\(C_T(t)\) is the time-dependent correction factor for the instrument degradation
\(C_E(t)\) is the time-dependent EVE correction factor
- Parameters:
obstime (
Time
, optional) – If specified, a time-dependent correction is applied to account for degradation.include_eve_correction (
bool
, optional) – If true andobstime
is notNone
, include correction to EVE calibration. The time-dependent correction is also included.include_crosstalk (
bool
, optional) – If true, include the effect of crosstalk between channels that share a telescopecorrection_table (
Table
orstr
, optional) – Table of correction parameters or path to correction table file. If not specified, it will be queried from JSOC. Seeaiapy.calibrate.util.get_correction_table
for more information.
- Return type:
See also
effective_area
,gain
,crosstalk
,eve_correction
,aiapy.calibrate.degradation