lco_etc.etc

Attributes

Filt

Ext

ApixelTable

gain_table

read_noise_table

dark_current_table

saturation_limit_table

phot_zeropoint_table

Msky

Carea

Fcent

Fband

Functions

moon_phase_to_numeric(→ int)

Convert moon phase from string to numeric value.

radial_integrate_gauss(→ float)

Calculates the radial integral of a Gaussian function.

telescope_to_index(→ int)

Convert telescope name to index.

exposure_time_calc(→ dict)

Exposure Time calculator for the Las Cumbres Observatory (LCO) network.

Module Contents

Filt = ['U', 'B', 'V', 'R', 'I', 'u', 'g', 'r', 'i', 'Z', 'Y'][source]
Ext = [0.54, 0.23, 0.12, 0.09, 0.04, 0.59, 0.14, 0.08, 0.06, 0.04, 0.03][source]
ApixelTable = [0.57, 0.389, 0.73, 0.304, 0.27][source]
gain_table = [1.6, 2.3, 0.7, 7.7, 1.9][source]
read_noise_table = [14, 8, 3, 11, 14.5][source]
dark_current_table = [0.02, 0.002, 0.04, 0.002, 0.005][source]
saturation_limit_table[source]
phot_zeropoint_table = [[18.0, 20.3, 20.7, 21.2, 20.3, 16.11, 21.4, 21.5, 20.75, 19.4, 17.8], [21.4, 23.5, 23.5, 23.8,...[source]
Msky = [[23.0, 22.5, 21.6, 20.6, 19.8, 23.5, 22.0, 21.1, 20.6, 20.2, 19.4], [20.0, 20.5, 20.3, 20.0,...[source]
Carea = [1200.0, 6260.0, 660, 27000.0, 27000.0][source]
Fcent = [0.35, 0.437, 0.549, 0.653, 0.789, 0.354, 0.476, 0.623, 0.76, 0.853, 0.975][source]
Fband = [0.05, 0.107, 0.083, 0.137, 0.128, 0.057, 0.14, 0.135, 0.148, 0.113, 0.118][source]
moon_phase_to_numeric(moon_phase: str) → int[source]

Convert moon phase from string to numeric value.

Parameters:

moon_phase (str) – Phase of the moon (new, half, full)

Returns:

Numeric value of the moon phase

Return type:

int

radial_integrate_gauss(R: float, sigma: float) → float[source]

Calculates the radial integral of a Gaussian function.

Parameters:

  • R (float) – Radius

  • sigma (float) – Standard deviation of the Gaussian that is based on the seeing

Returns:

Radial integral of the Gaussian function

Return type:

float

telescope_to_index(telescope: str) → int[source]

Convert telescope name to index.

Parameters:

telescope (str) – Name of the telescope

Returns:

Index of the telescope

Return type:

int

exposure_time_calc(snr: float, magnitude: float, etime: float, telescope: str, filter: str, moon_phase: str, airmass: float, seeing: float = 2) → dict[source]

Exposure Time calculator for the Las Cumbres Observatory (LCO) network.

Given two of the three values (S/N, magnitude, and exposure time), this function calculates the third value.

This function is based on the LCO exposure time calculator available at https://exposure-time-calculator.lco.global/

The javascript code for the original calculator was extracted from the webpage and translated to Python.

Make sure that the filter is available on the selected instrument!

Information about each telescope can be found at https://lco.global/observatory/instruments/

UBVRI in Vega magnitudes; ugriz in AB magnitudes

Parameters:

  • snr (float) – Signal-to-noise ratio

  • magnitude (float) – Magnitude

  • etime (float) – Exposure time

  • telescope (str) – Telescope name (sbig, sinistro, qhy, spectral, muscat3)

  • filter (str) – Filter (U, B, V, R, I, u, g, r, i, Z, Y)

  • moon_phase (int) – Moon phase

  • airmass (float) – Airmass

  • seeing (float, optional) – Seeing in arcseconds (default is 2)

Returns:

A dictionary containing the calculated values: - snr : float

Signal-to-noise ratio

  • magnitudefloat

    Magnitude

  • exposure_timefloat

    Exposure time

  • saturatedbool

    True if the source is saturated

  • mag_systemstr

    Magnitude system (Vega or AB)

Return type:

dict