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.descriptors attribute:

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

>> ad.descriptors
('airmass', 'amp_read_area', 'ao_seeing', ..., 'well_depth_setting')

To get the values:

>> ad.airmass()

>> for descriptor in ad.descriptors:
...     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 use.	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