Exposure time calculator for APO/ARCES

Calculate S/N and exposure times for stellar spectroscopy with the ARC Echelle Spectrograph (ARCES) on the ARC 3.5 m Telescope at Apache Point Observatory.

The ARC Echelle Spectroscopic (ARCES) Exposure Time Calculator, or arcesetc, is a simple exposure time calculator for the ARCES instrument on the Astrophysical Research Consortium (ARC) 3.5 m Telescope at Apache Point Observatory for stellar spectroscopy. Users can supply arcesetc functions with the spectral type of their target star, the V band magnitude, and either: the desired exposure time in order to determine the counts and signal-to-noise ratio as a function of wavelength; or the desired signal-to-noise ratio at a given wavelength to determine the required exposure time.

We estimate the count rates for stars as a function of wavelength by fitting 15th-order polynomials to each spectral order of real observations of a star of each spectral type. These polynomial coefficients and some wavelength metadata are stored in an HDF5 archive for compactness and easy of reconstruction. Then upon calling arcesetc, the archive is opened and the spectral order closest to the wavelength of interest is reconstructed from the polynomial coefficients, for a star of the closest available spectral type to the one requested.

Installation

You can install arcesetc with pip:

pip install arcesetc

You can install arcesetc from the source code by doing the following:

git clone https://github.com/bmorris3/arcesetc.git
cd arcesetc
pip install .

arcesetc requires python >=3.5, numpy, astropy, h5py, and matplotlib.

For more information, read the docs.

License

This project is Copyright (c) Brett Morris & Trevor Dorn-Wallenstein and licensed under the terms of the MIT license. This package is based upon the Astropy package template which is licensed under the BSD 3-clause licence. See the licenses folder for more information.