Perform photometry on images from the Large Monolithic Imager at the Discovery Channel Telescope.

This module contains three functions that produce useful photometry from raw .FITS images from LMI at DCT. To use, simply follow this example.

numpy, scipy, matplotlib, astropy, ccdproc, astroquery, photutils

func LMI_Photometry. Data_Reduction (directory, filters, targets, save_to=None, dark_exp=1.0, subtract_dark=False)

Creates and applies a master bias, flat, and dark (optional) frame to science images, saves in directory, and updates the .FITS header to make targets Simbad-compatible.

• Parameters:

  directory : str

  A directory containing raw .FITS images and calibration frames

  filters : dict

  Filters used and corresponding flat exposures

  {'filter' : flat exposure}
  

  targets : dict

  "SCITARG" name in .FITS header and corresponding name in Simbad

  {'FITS target name' : 'Simbad target name'}
  

  save_to : str, optional (default=None)

  Optional second directory to save calibrated frames to

  dark_exp : float, optional (default=1.0)

  Exposure time for dark frames

  subtract_dark : bool, optional (default=False)

  Set to True in order to subtract dark frame

  Note: LMI has negligible dark current

• Returns:

  None

func LMI_Photometry. Aperture_Photometry (directory, ap_radius, standards, show_figures=False)

Measures raw electron counts for a target star and utilizes the .FITS header to calculate and save fluxes and instrumental magnitudes. Flags specified stars as standards to be used for standard magnitude transformations.

• Parameters:

  directory : str

  A directory containing reduced .FITS images

  ap_radius : int

  Radius of aperture used for photometry

  standards : dict

  Simbad-compatible name with list of standard star names in the field

  {'Query Name' : ['Standard Query Name', 'Standard Query Name']}
  

  show_figures : bool, optional (default=False)

  Display optional figures that are relevant

• Returns:

  None

func LMI_Photometry. Convert_Magnitudes (directory, filters, bin_size=10, show_figures=False)

Reads magnitudes and airmass values saved in the .FITS headers of standard stars, calculates a magnitude transformation for each filter used, then applies the transformation to science images to convert their instrumental magnitudes to standard magnitudes. Saves measurements and uncertainties in a .txt table in ascii format.

• Parameters:

  directory : str

  A directory containing reduced .FITS images instrumental magnitudes appended to the .FITS header

  filters : list

  A list of filters used

  ['filter 1', 'filter 2']
  

  bin_size : int, optional (default=10)

  Number of epochs target is observed

  show_figures : bool, optional (default=False)

  Display optional figures that are relevant

• Returns:

  None

Displays a given .FITS image. Useful for visual inspection for hot pixels, cosmic rays, saturation, etc.

An example of how to use LMI_Photometry.py