exoctk.groups_integrations package

Submodules

exoctk.groups_integrations.groups_integrations module

This is a module for calcuating groups and integrations with JWST on the fly. The main function (perform_calculation) takes a dictionary of inputs (modeled around how the web tool takes inputs) which must include: observation_time, num_groups, magnitude, model, band, filt, filt_ta, instrument, subarray, subarray_ta, saturation_mode, max_saturation, and infile. It produces and dictionary of outputs that includes all of the original information as well as groups, integrations, saturation levels, and observation time estimates for target acquisition and science observations with JWST.

Authors

Jules Fowler, April 2017 Matthew Bourque, February 2021

Use

This is mostly a module to be used by the ExoCTK web application, but the main function can be run standalone as such:

from exoctk.groups_integrations.groups_integrations import perform_calculation
perform_calculation()

Dependencies

• astropy

• numpy

• scipy

exoctk.groups_integrations.groups_integrations.calc_duration_time(num_groups, num_integrations, num_reset_frames, frame_time, frames_per_group=1)

Calculates duration time (or exposure duration as told by APT)

Parameters:

num_groupsint

Groups per integration

num_integrationsint

Integrations per exposure

num_reset_framesint

Reset frames per integration

frame_timefloat

Frame time (in seconds)

frames_per_groupint, optional

Frames per group – always one except brown dwarves

Returns:

duration_timefloat

Duration time (in seconds).

exoctk.groups_integrations.groups_integrations.calc_exposure_time(num_integrations, ramp_time)

Calculates exposure time (or photon collection duration as told by APT.)

Parameters:

num_integrationsint

Integrations per exposure.

ramp_timefloat

Ramp time (in seconds).

Returns:

exposure_timefloat

Exposure time (in seconds).

exoctk.groups_integrations.groups_integrations.calc_frame_time(num_columns, num_rows, num_amps, instrument)

Calculates the frame time for a given instrument/readmode/subarray.

Parameters:

num_columnsint

Number of columns

num_rowsint

Number of rows

num_ampsint

Amplifiers reading data

instrumentstr

The instrument

Returns:

frame_timefloat

The frame time (in seconds)

exoctk.groups_integrations.groups_integrations.calc_groups_from_exp_time(max_exptime_per_int, frame_time)

Given the maximum saturation time, calculates the number of frames per group.

Parameters:

max_exptime_per_intfloat

The maximum number of seconds an integration can last before it’s oversaturated

frame_timefloat

The time per frame

Returns:

groupsint

The required number of groups.

exoctk.groups_integrations.groups_integrations.calc_integration_time(num_groups, frame_time, frames_per_group, num_skips)

Calculates the integration time.

Parameters:

num_groupsint

Groups per integration.]

frame_timefloat

Frame time (in seconds)

frames_per_groupint

Frames per group – always 1 except maybe brown dwarves

num_skipsint

Skips per integration – always 0 except maybe brown dwarves

Returns:

integration_timefloat

Integration time (in seconds)

exoctk.groups_integrations.groups_integrations.calc_num_integrations(transit_time, num_groups, num_reset_frames, frame_time, frames_per_group)

Calculates number of integrations required.

Parameters:

transit_timefloat

The time of the transit (in hours)

num_groupsint

Groups per integration

num_reset_framesint

Number of reset frames per integration

frame_timefloat

The frame time (in seconds)

frames_per_groupint

Frames per group – always 1 except maybe for brown dwarves

Returns:

num_integrationsfloat

The required number of integraitions.

exoctk.groups_integrations.groups_integrations.calc_observation_efficiency(exposure_time, duration_time)

Calculates the observation efficiency.

Parameters:

exposure_timefloat

Exposure time (in seconds).

duration_timefloat

Duration time (in seconds).

Returns:

observation_efficiencyfloat

Observation efficiency.

exoctk.groups_integrations.groups_integrations.calc_ramp_time(integration_time, num_reset_frames, frame_time)

Calculates the ramp time – or the integration time plus overhead for resets.

Parameters:

integration_timefloat

Integration time (in seconds)

num_reset_framesint

Rest frames per integration

frame_timefloat

Frame time (in seconds)

Returns:

ramp_timefloat

Ramp time (in seconds).

exoctk.groups_integrations.groups_integrations.convert_saturation(max_saturation, saturation_mode, instrument, infile, target_acq_mode=False)

Converts full well fraction to a saturation in counts OR provides the max fullwell for TA mode.

Parameters:

max_saturationfloat

Either a full well fraction or counts

saturation_modestr

well or counts

instrumentstr

The instrument

infilestr

The path to the data file

target_acq_modebool, optional

Whether or not it’s TA mode

Returns:

max_saturationfloat

The fullwell to use in counts.

exoctk.groups_integrations.groups_integrations.interpolate_from_pandeia(magnitude, instrument, filt, subarray, model, band, frame_time, saturation_level, infile, target_acq_mode=False)

Interpolates the precalculated pandeia data to estimate the saturation limit.

Parameters:

magnitudefloat

The magnitude of the source. (Takes between 4.5-12.5)

instrumentstr

The instrument, allowable miri, niriss, nirspec, nircam

filtstr

The filter

subarraystr

The subarray

modelstr

Phoenix model key

bandstr

Magnitude band

frame_timefloat

Frame time

saturation_levelfloat

The maximum fullwell saturation we’ll allow

infilestr

The data file to use

target_acq_modebool, optional

Whether or not we’re running this for TA

Returns:

num_groupsint

The number of groups that won’t oversaturate the detector

max_satint

The maximum saturation level reached by that number of groups

exoctk.groups_integrations.groups_integrations.map_to_ta_modes(instrument, max_num_groups, min_num_groups)

Turns the min/max groups into the closest allowable TA group mode.

Parameters:

instrumentstr

The instrument

max_num_groupsint

The maximum number of groups without oversaturating

min_num_groupsint

The groups needed to hit the target SNR

Returns:

min_ta_groupsint

The min possible groups to hit target SNR

max_ta_groupsint

The max possible groups before saturation

exoctk.groups_integrations.groups_integrations.min_num_groups_for_sat(magnitude, instrument, filt, subarray, model, band, infile)

Estimates the minimum number of groups to reach target acq saturation requirements.

Parameters:

magnitudefloat

Magnitude of star.

instrumentstr

Instrument.

filtstr

Filter.

subarraystr

Subarray.

modelstr

Phoenix model key.

bandstr, currently unused?

The band – right now only k sooo?

infilestr

The file with the pandeia data.

Returns:

min_num_groups_for_satint

The minimum number of groups to reach target snr.

exoctk.groups_integrations.groups_integrations.perform_calculation(params, frames_per_group=1, num_skips=0)

Calculates all of the outputs and puts them in a dictionary for easy access.

Parameters:

paramsdict

Dictionary of all the needed parameters. Must include: obs_time, n_group, mag, mod, band, filt, filt_ta, ins, subarray, subarray_ta, sat_mode, max_sat, infile

frames_per_groupint, optional

The number of frames – almost always 1

num_skips: int, optional

Number of skips – almost always 0

Returns:

paramsdict, str

Dictionary of outputs and inputs. If the calculation throws an error it will return a string error message instead

exoctk.groups_integrations.groups_integrations.set_frame_time(infile, instrument, subarray, target_acq_mode=False)

Assign the appropriate frame time based on the instrument and subarray. For now, modes are implied.

Parameters:

infile: str

The path to the data file.

instrumentstr

The instrument : miri, niriss, nirspec, or nircam

subarraystr

The subarray

target_acq_modebool

Whether this is for TA or not.

Returns:

frame_timefloat

The frame time for this instrument/subarray combo.

exoctk.groups_integrations.groups_integrations.set_params_from_instrument(instrument, subarray)

Sets/collects the running parameters from the instrument.

Parameters:

instrumentstr

Instrument, options are nircam, niriss, nirpec, and miri

subarraystr

Subarray mode

Returns:

rowsint

The number of pixels per row.

colsint

The number of columns per row.

ampsint

The number of amplifiers.

pixel_sizeint

The pixel size.

frame_timefloat

The frame time.

num_reset_framesint

The number of reset frames.

Module contents