mag_estimator#

class arte.photometry.mag_estimator.MagEstimator(telescope, detector_bandname, total_adus=<Quantity 1. adu>, detector_bandwidth=<Quantity 300. nm>, detector_freq=<Quantity 1. Hz>, detector_gain=1, detector_adu_e_ratio=<Quantity 1. electron / adu>, detector_nsubaps=1, wfs_transmission=1.0, detector_qe=<Quantity 1. electron / ph>)#

Bases: object

Estimates magnitude from detector counts

Parameters:

  • total_adus (int * u.adu) – total ADUs recorded by the detector in one exposure

  • telescope (class Telescope or equivalent) – a class that defines an area() method with a result in u.m**2

  • detector_bandname (str) – one of the allowed bandnames (use MagEstimator.bandnames() to list)

  • detector_bandwidth (float * u.nm, optional) – bandwidth, defaults to 300 nm

  • detector_gain (int, optional) – detector EM gain, defaults to 1

  • detector_adu_e_ratio (float * u.electron/u.adu) – detector ADU/e- conversion factor, defaults to 1.0

  • detector_nsubaps (int, optional) – number of subapertures, defaults to 1

  • detector_freq (float * u.Hz, optional) – detector frequency, defaults to 1.0 Hz

  • wfs_transmission (float, optional) – overall wfs transmission from telescope aperture to detector, defaults to 1

  • detector_qe (float * u.electron/u.ph, optional) – average QE over the considered band, defaults to 1.0

Raises:

TypeError – if the wrong astropy units are passed in the initializer

Notes

From https://www.eso.org/observing/etc/doc/skycalc/helpskycalc.html#mags

(flux for zero mag in Vega system)
Band   Photometric zeropoint in ergs/s/cm2/A
 U     U0 = 4.18023e-09
 B     B0 = 6.60085e-09
 V     V0 = 3.60994e-09
 R     R0 = 2.28665e-09
 I     I0 = 1.22603e-09
 Z     Z0 = 7.76068e-10
 Y     Y0 = 5.973e-10
 J     J0 = 3.12e-10
 H     H0 = 1.14e-10
 K     K0 = 3.94e-11
 L     L0 = 4.83e-12
 M     M0 = 2.04e-12
 N     N0 = 1.23e-13
 Q     Q0 = 6.8e-15

Methods

bandname()

Name of the band used for magnitude estimation

bandnames()

List of supported bandnames

flux_zero()

Zero point in photons/sec

help([search, prefix])

Interactive help

mag()

Estimated magnitude

photons_per_second()

Photons/sec detected by sensor

photons_per_subap_per_frame()

Photons/subap/frame detected by sensor
bandname()#

Name of the band used for magnitude estimation

bandnames()#

List of supported bandnames

flux_zero()#

Zero point in photons/sec

help(search='', prefix='')#

Interactive help

Prints on stdout a list of methods that match the search substring or all of them if search is left to the default value of an empty string, together with a one-line help taken from the first line of their docstring, if any.

The prefix argument is prepended to the method name and is used for recursive help of every class member.

mag()#

Estimated magnitude

photons_per_second()#

Photons/sec detected by sensor

photons_per_subap_per_frame()#

Photons/subap/frame detected by sensor