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:

channel (Quantity) – Wavelength of AIA channel.
instrument_file (str, optional) – Path to AIA instrument file. If not specified, the latest version will be downloaded from SolarSoft.

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

`channel`	Nominal wavelength at which the bandpass of the channel is centered.
`contamination`
`crosstalk`	Contamination of effective area from crosstalk between channels.
`effective_area`	Uncorrected effective area as a function of wavelength.
`entrance_filter_efficiency`
`focal_plane_filter_efficiency`
`gain`	Gain of the CCD camera system.
`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.
`wavelength`	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

[boerner]

Boerner et al., 2012, Sol. Phys., 275, 41

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

[boerner1]

Boerner et al., 2012, Sol. Phys., 275, 41

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 or str, 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:

Quantity