List of Gemini Standard Descriptors

To run and re-use Gemini primitives and functions this list of Standard Descriptors must be defined for input data. This also applies to data that is to be served by the Gemini Observatory Archive (GOA).

For any AstroData objects, to get the list of the descriptors that are defined use the astrodata.descriptor_list() function:

>>> import astrodata
>>> import gemini_instruments
>>> ad = astrodata.open('../playdata/N20170609S0154.fits')

>>> astrodata.descriptor_list(ad)

To get the values:

>>> ad.airmass()

>>> for descriptor in astrodata.descriptor_list(ad):
...     print(descriptor, getattr(ad, descriptor)())
...

Note that not all of the descriptors below are defined for all of the instruments. For example, shuffle_pixels is defined only for GMOS data since only GMOS offers a Nod & Shuffle mode.

Descriptor Short Definition Python type
    ad[0].desc()
ad.desc()
airmass Airmass of the observation. float
amp_read_area Combination of amplifier name and 1-indexed section relative to the detector. str
list of str
ao_seeing Estimate of the natural seeing as calculated from the adaptive optics systems. float
array_name Name assigned to the array generated by a given amplifier, one array per amplifier. str
list of str
array_section Section covered by the array(s), in 0-indexed pixels, relative to the detector frame (e.g. position of multiple amps read within a CCD). Uses namedtuple “Section” defined in gemini_instruments.common. Section
list of Section
azimuth Pointing position in azimuth, in degrees. float
calibration_key Key used in the database that the getProcessed* primitives use to store previous calibration association information. str
camera Name of the camera. str
cass_rotator_pa Position angle of the Cassegrain rotator, in degrees. float
central_wavelength Central wavelength, in meters. float
coadds Number of co-adds. int
data_label Gemini data label. str
data_section Section where the sky-exposed data falls, in 0-indexed pixels. Uses namedtuple “Section” defined in gemini_instruments.common Section
list of Section
dec Declination of the center of the field, in degrees. float
decker Name of the decker. str
detector_name Name assigned to the detector. str
detector_roi_setting Human readable Region of Interest (ROI) setting str
detector_rois_requested Section defining the Regions of Interest, in 0-indexed pixels. Uses namedtuple “Section” defined in gemini_instruments.common. list of Section
detector_section Section covered by the detector(s), in 0-indexed pixels, relative to the whole mosaic of detectors. Uses namedtuple “Section” defined in gemini_instruments.common. list
list of Section
detector_x_bin X-axis binning. int
detector_x_offset Telescope offset along the detector X-axis, in pixels. float
detector_y_bin Y-axis binning. int
detector_y_offset Telescope offset along the detector Y-axis, in pixels. float
disperser Name of the disperser. str
dispersion Value for the dispersion, in meters per pixel. float
list of float
dispersion_axis Dispersion axis. int
list of int
effective_wavelength Wavelength representing the bandpass or the spectrum coverage. float
elevation Pointing position in elevation, in degrees. float
exposure_time Exposure time, in seconds. float
filter_name Name of the filter combination. str
focal_plane_mask Name of the mask in the focal plane. str
gain Gain in electrons per ADU float
list of float
gain_setting Human readable gain setting (eg. low, high) str
gcal_lamp Returns the name of the GCAL lamp being used, or “Off” if no lamp is in used. str
group_id Gemini observation group ID that identifies compatible data. str
instrument Name of the instrument str
is_ao Whether or not the adaptive optics system was used. bool
is_coadds_summed Whether co-adds are summed or averaged. bool
local_time Local time. datetime
lyot_stop Name of the lyot stop. str
mdf_row_id Mask Definition File row ID of a cut MOS or XD spectrum. int ??
nod_count Number of nods to A and B positions. tuple of int
nod_offsets Nod offsets to A and B positions, in arcseconds tuple of float
nominal_atmospheric_extinction Nomimal atmospheric extinction, from model. float
nominal_photometric_zeropoint Nominal photometric zeropoint. float
list of float
non_linear_level Lower boundary of the non-linear regime. float
list of int
object Name of the target (as entered by the user). str
observation_class Gemini class name for the observation (eg. ‘science’, ‘acq’, ‘dayCal’). str
observation_epoch Observation epoch. float
observation_id Gemini observation ID. str
observation_type Gemini observation type (eg. ‘OBJECT’, ‘FLAT’, ‘ARC’). str
overscan_section Section where the overscan data falls, in 0-indexed pixels. Uses namedtuple “Section” defined in gemini_instruments.common. Section
list of Section
pixel_scale Pixel scale in arcsec per pixel. float
program_id Gemini program ID. str
pupil_mask Name of the pupil mask. str ??
qa_state Gemini quality assessment state (eg. pass, usable, fail). str
ra Right ascension, in degrees. float
raw_bg Gemini sky background band. int ??
raw_cc Gemini cloud coverage band. int
raw_iq Gemini image quality band. int
raw_wv Gemini water vapor band. int ??
read_mode Gemini name for combination for gain setting and read setting. str
read_noise Read noise in electrons. float
list of float
read_speed_setting human readable read mode setting (eg. slow, fast). str
requested_bg PI requested Gemini sky background band. int
requested_cc PI requested Gemini cloud coverage band. int
requested_iq PI requested Gemini image quality band. int
requested_wv PI requested Gemini water vapor band. int
saturation_level Saturation level. int
list of int
shuffle_pixels Charge shuffle, in pixels. (nod and shuffle mode) int
slit Name of the slit. str
target_dec Declination of the target, in degrees. float
target_ra Right Ascension of the target, in degrees. float
telescope Name of the telescope. str
telescope_x_offset Offset along the telescope’s x-axis. float
telescope_y_offset Offset along the telescope’s y-axis. float
ut_date UT date of the observation. datetime.date
ut_datetime UT date and time of the observation. datetime
ut_time UT time of the observation. datetime.time
wavefront_sensor Wavefront sensor used for the observation. str
wavelength_band Band associated with the filter or the central wavelength. str
wcs_dec Declination of the center of field from the WCS keywords. In degrees. float
wcs_ra Right Ascension of the center of field from the WCS keywords. In degrees. float
well_depth_setting Human readable well depth setting (eg. shallow, deep) str