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 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