A Complete List of Available DescriptorsΒΆ

Descriptors are designed such that essential keyword values that describe a particular concept can be accessed from the headers of any dataset in a consistent manner, regardless of which instrument was used to obtain the data. This is particularly useful for Gemini data, since the majority of keywords used to describe a particular concept at Gemini are not uniform between the instruments.

airmass

  • the mean airmass of the observation

amp_read_area

  • the composite string containing the name of the array amplifier and the readout area of the array used for the observation

array_section

  • the unbinned section (in the form of a Python list of integers that uses 0-based indexing as default) of the array that was used to observe the data

azimuth

  • the azimuth (in degrees between 0 and 360) of the observation

bias_level

  • the bias level (in ADU) of the observation

camera

  • the camera used for the observation

cass_rotator_pa

  • the cassegrain rotator position angle (in degrees between -360 and 360) of the observation

central_wavelength

  • the central wavelength (in meters as default) of the observation

coadds

  • the number of coadds used for the observation

data_label

  • the unique identifying name (e.g., GN-2003A-C-2-52-003) of the observation

data_section

  • the section (in the form of a Python list of integers that uses 0-based indexing as default) of the pixel data extensions that contains the data observed

decker

  • the decker position used for the observation

dec

  • the declination (in decimal degrees) of the observation

detector_name

  • the name of each array used for the observation

detector_roi_setting

  • the human-readable description of the detector Region Of Interest (ROI) setting (either ‘Full Frame’, ‘CCD2’, ‘Central Spectrum’, ‘Central Stamp’, ‘Custom’, ‘Undefined’ or ‘Fixed’), which corresponds to the name of the ROI in the OT

detector_rois_requested

  • the requested detector Region Of Interest (ROI)s of the observation

detector_section

  • the unbinned section (in the form of a Python list of integers that uses 0-based indexing as default) of the detector that was used to observe the data

detector_x_bin

  • the binning of the x-axis of the detector used for the observation

detector_y_bin

  • the binning of the y-axis of the detector used for the observation

disperser

  • the disperser used for the observation - difference between disperser/grating/prism? when should someone use disperser? *******************************************

dispersion_axis

  • the dispersion axis (along rows, x = 1; along columns, y = 2; along planes, z = 3) of the observation.

dispersion

  • the dispersion (in meters per pixel as default) of the observation

elevation

  • the elevation (in degrees) of the observation

exposure_time

  • the total exposure time (in seconds) of the observation

filter_name

  • the unique filter name identifier string used for the observation; when multiple filters are used, the filter names are concatenated with an ampersand

focal_plane_mask

  • the focal plane mask used for the observation

gain

  • the gain (in electrons per ADU) of the observation

gain_setting

  • the gain setting (either ‘high’ or ‘low’) of the observation

grating

  • the grating used for the observation

group_id

  • the unique string that describes which stack a dataset belongs to; it is based on the observation_id

instrument

  • the instrument used for the observation

local_time

  • the local time (in HH:MM:SS.S) at the start of the observation

mdf_row_id

  • the corresponding reference row in the Mask Definition File (MDF)

nod_count

  • the number of nod and shuffle cycles in the nod and shuffle observation

nod_pixels

  • the number of pixel rows the charge is shuffled by in the nod and shuffle observation

nominal_atmospheric_extinction

  • the nominal atmospheric extinction (defined as coeff * (airmass - 1.0), where coeff is the site and filter specific nominal atmospheric extinction coefficient) of the observation

nominal_photometric_zeropoint

  • the nominal photometric zeropoint of the observation

non_linear_level

  • the non linear level in the raw images (in ADU) of the observation

object

  • the name of the target object observed

observation_class

  • the class (either ‘science’, ‘progCal’, ‘partnerCal’, ‘acq’, ‘acqCal’ or ‘dayCal’) of the observation

observation_epoch

  • the epoch (in years) at the start of the observation

observation_id

  • the ID (e.g., GN-2011A-Q-123-45) of the observation; it is used by group_id

observation_type

  • the type (either ‘OBJECT’, ‘DARK’, ‘FLAT’, ‘ARC’, ‘BIAS’ or ‘MASK’) of the observation

overscan_section

  • the section (in the form of a Python list of integers that uses 0-based indexing as default) of the pixel data extensions that contains the overscan data

pixel_scale

  • the pixel scale (in arcsec per pixel) of the observation

prism

  • the prism used for the observation

program_id

  • the Gemini program ID (e.g., GN-2011A-Q-123) of the observation

pupil_mask

  • the pupil mask used for the observation

qa_state

  • the quality assessment state (either ‘Undefined’, ‘Pass’, ‘Usable’, ‘Fail’ or ‘CHECK’) of the observation

ra

  • the Right Ascension (in decimal degrees) of the observation

raw_bg

  • the raw background (as an integer percentile value) of the observation

raw_cc

  • the raw cloud cover (as an integer percentile value) of the observation

raw_iq

  • the raw image quality (as an integer percentile value) of the observation

raw_wv

  • the raw water vapour (as an integer percentile value) of the observation

read_mode

  • the read mode (either ‘Very Faint Object(s)’, ‘Faint Object(s)’, ‘Medium Object’, ‘Bright Object(s)’, ‘Very Bright Object(s)’, ‘Low Background’, ‘Medium Background’, ‘High Background’ or ‘Invalid’) of the observation

read_noise

  • the estimated readout noise (in electrons) of the observation

read_speed_setting

  • the read speed setting (either ‘fast’ or ‘slow’) of the observation

requested_bg

  • the requested background (as an integer percentile value) of the observation

requested_cc

  • the requested cloud cover (as an integer percentile value) of the observation

requested_iq

  • the requested image quality (as an integer percentile value) of the observation

requested_wv

  • the requested water vapour (as an integer percentile value) of the observation

saturation_level

  • the saturation level (in ADU) of the observation

slit

  • the name of the slit used for the observation

telescope

  • the telescope used for the observation

ut_date

  • the UT date (as a datetime object) at the start of the observation

ut_datetime

  • the UT date and time (as a datetime object) at the start of the observation

ut_time

  • the UT time (as a datetime object) at the start of the observation

wavefront_sensor

  • the wavefront sensor (either ‘AOWFS’, ‘OIWFS’, ‘PWFS1’, ‘PWFS2’, some combination in alphabetic order separated with an ampersand or None) used for the observation

wavelength_band

  • the wavelength band name (e.g., J, V, R, N) of the observation

wavelength_reference_pixel

  • the 1-based reference pixel of the central wavelength of the observation

well_depth_setting

  • the well depth setting (either ‘Shallow’, ‘Deep’ or ‘Invalid’) of the observation

x_offset

  • the telescope offset in x (in arcsec) of the observation

y_offset

  • the telescope offset in y (in arcsec) of the observation

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