A Complete List of Available Descriptors
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