Source code for gemini_instruments.gmu

# This module should be removed when we have a working gempy for new astrodata

import math
import re
from astropy import coordinates, units

# The unitDict dictionary defines the factors for the function
# convert_units
unitDict = {
    'meters': 0,
    'micrometers': -6,
    'nanometers': -9,
    'angstroms': -10,

[docs]def isBlank(bstring): return not (bstring and bstring.strip())
[docs]def removeComponentID(instr): """ Remove a component ID from a filter name :param instr: the filter name :type instr: string :rtype: string :return: the filter name with the component ID removed, or `None` if the input is not a valid string """ try: m = re.match(r"(?P<filt>.*?)_G(.*?)", instr) except TypeError: return None if not m: # There was no "_G" in the input string. Return the input string ret_str = str(instr) else: ret_str = str("filt")) return ret_str
[docs]def sectionStrToIntList(section): """ Convert the input section in the form '[x1:x2,y1:y2]' to a tuple in the form (x1 - 1, x2, y1 - 1, y2), where x1, x2, y1 and y2 are integers. The values in the output tuple are converted to use 0-based and non-inclusive indexing, making it compatible with numpy. Parameters ---------- section : str The section (in the form [x1:x2,y1:y2]) to be converted to a tuple. Returns ------- tuple : the converted section as a tuple that uses 0-based and non-inclusive in the form (x1 - 1, x2, y1 - 1, y2). """ # Strip the square brackets from the input section and then create a # list in the form ['x1:x2','y1:y2'] xylist = section.strip('[]').split(',') # Create variables containing the single x1, x2, y1 and y2 values x1 = int(xylist[0].split(':')[0]) - 1 x2 = int(xylist[0].split(':')[1]) y1 = int(xylist[1].split(':')[0]) - 1 y2 = int(xylist[1].split(':')[1]) # Return the tuple in the form (x1 - 1, x2, y1 - 1, y2) return x1, x2, y1, y2
[docs]def parse_percentile(string): # Given the type of string that ought to be present in the site condition # headers, this function returns the integer percentile number # # Is it 'Any' - ie 100th percentile? if (string == "Any"): return 100 # Is it a xx-percentile string? try: m = re.match(r"^(\d\d)-percentile$", string) except TypeError: return None if m: return int( # We didn't recognise it return None
[docs]def convert_units(input_units, input_value, output_units): """ :param input_units: the units of the value specified by input_value. Possible values are 'meters', 'micrometers', 'nanometers' and 'angstroms'. :type input_units: string :param input_value: the input value to be converted from the input_units to the output_units :type input_value: float :param output_units: the units of the returned value. Possible values are 'meters', 'micrometers', 'nanometers' and 'angstroms'. :type output_units: string :rtype: float :return: the converted value of input_value from input_units to output_units """ # Determine the factor required to convert the input_value from the # input_units to the output_units power = unitDict[input_units] - unitDict[output_units] factor = math.pow(10, power) # Return the converted output value if input_value is not None: return input_value * factor
[docs]def toicrs(frame, ra, dec, equinox=2000.0, ut_datetime=None): # Utility function. Converts and RA and Dec in the specified reference frame # and equinox at ut_datetime into ICRS. This is used by the ra and dec descriptors. # Assume equinox is julian calendar equinox = 'J{}'.format(equinox) # astropy doesn't understand APPT coordinates. However, it does understand # CIRS coordinates, and we can convert from APPT to CIRS by adding the # equation of origins to the RA. We can get that using ERFA. # To proceed with this, we first let astopy construct the CIRS frame, so # that we can extract the obstime object from that to pass to erfa. appt_frame = (frame == 'APPT') if frame == 'APPT': frame = 'cirs' if frame == 'FK5': frame = 'fk5' # Try this with the passed frame but, if it doesn't work, convert to "cirs" # If that doesn't work, then raise an error try: coords = coordinates.SkyCoord(ra=ra*, dec=dec*, frame=frame, equinox=equinox, obstime=ut_datetime) except ValueError: frame = 'cirs' coords = coordinates.SkyCoord(ra=ra*, dec=dec*, frame=frame, equinox=equinox, obstime=ut_datetime) if appt_frame: # Call ERFA.apci13 to get the Equation of Origin (EO). # We just discard the astrom context return try: # With astropy 4.2 erfa becomes a dependency and lives in an # independent Python package: import erfa except ImportError: from astropy import _erfa as erfa astrom, eo = erfa.apci13(coords.obstime.jd1, coords.obstime.jd2) # eo comes back as a single element array in radians eo = float(eo) eo = eo * units.radian # re-create the coords frame object with the corrected ra coords = coordinates.SkyCoord(ra=coords.ra+eo, dec=coords.dec,, equinox=coords.equinox, obstime=coords.obstime) # Now we can just convert to ICRS... icrs = coords.icrs # And return values in degrees return (,
[docs]def detsec_to_pixels(ad, detx, dety): # Utility function to convert a location in "detector section pixels" to # an image extension and real pixels on that extension. xbin, ybin = ad.detector_x_bin(), ad.detector_y_bin() for i, detsec in enumerate(ad.detector_section()): if (detx < detsec.x1 or detx >= detsec.x2 or dety < detsec.y1 or dety >= detsec.y2): continue datasec = ad.data_section()[i] return (i, datasec.x1 + (detx - detsec.x1) // xbin, datasec.y1 + (dety - detsec.y1) // ybin) return None
### END temporary functions