scopesim.utils module

Helper functions for ScopeSim

scopesim.utils.add_SED_to_scopesim(file_in, file_out=None, wave_units='um')

Adds the SED given in file_in to the ScopeSim data directory

Parameters:

file_instr

path to the SED file. Can be either FITS or ASCII format with 2 columns Column 1 is the wavelength, column 2 is the flux

file_outstr, optional

Default is None. The file path to save the ASCII file. If None, the SED is saved to the ScopeSim data directory i.e. to rc.__data_dir__

wave_unitsstr, astropy.Units

Units for the wavelength column, either as a string or as astropy units Default is [um]

scopesim.utils.add_keyword(filename, keyword, value, comment='', ext=0)

Add a keyword, value pair to an extension header in a FITS file

Parameters:

filenamestr

Name of the FITS file to add the keyword to

keywordstr

valuestr, float, int

commentstr

extint, optional

The fits extension index where the keyword should be added. Default is 0

scopesim.utils.add_mags(mags)

Returns a combined magnitude for a group of py_objects with mags

scopesim.utils.airmass2zendist(airmass)

Convert airmass to zenith distance

Parameters:

airmassfloat (>= 1)

Returns:

zenith distance in degrees

scopesim.utils.airmass_to_zenith_dist(airmass)

returns zenith distance in degrees

Z = arccos(1/X)

scopesim.utils.angle_in_arcseconds(distance, width)

Returns the angular distance of an object in arcseconds.

Units must be consistent!

scopesim.utils.bug_report()

Get versions of dependencies for inclusion in bug report

scopesim.utils.change_table_entry(tbl, col_name, new_val, old_val=None, position=None)

scopesim.utils.check_keys(input_dict, required_keys, action='error', all_any='all')

Checks to see if all/any of the required keys are present in a dict

scopesim.utils.clean_dict(orig_dict, new_entries)

Used for replacing OBS_DICT keywords with actual values

Parameters:

orig_dictdict

new_entriesdict

OBS dict

Returns:

orig_dictdict

Updated dict

scopesim.utils.convert_table_comments_to_dict(tbl)

scopesim.utils.deg2rad(theta)

scopesim.utils.deriv_polynomial2d(poly)

Derivatives (gradient) of a Polynomial2D model

Parameters:

polyastropy.modeling.models.Polynomial2D

scopesim.utils.dist_mod_from_distance(d)

mu = 5 * np.log10(d) - 5

scopesim.utils.distance_from_dist_mod(mu)

d = 10**(1 + mu / 5)

scopesim.utils.empty_type(x)

scopesim.utils.extract_base_from_unit(unit, base_unit)

Extract astropy base unit from a compound unit

Parameters:

unitastropy.Unit

base_unitUnit, str

Returns:

new_unitUnit

The input unit minus any base units corresponding to base_unit

extracted_unitsUnit

Any base units corresponding to base_unit

scopesim.utils.extract_type_from_unit(unit, unit_type)

Extract astropy physical type from a compound unit

Parameters:

unitastropy.Unit

unit_typestr

The physical type of the unit as given by astropy

Returns:

new_unitUnit

The input unit minus any base units corresponding to unit_type

extracted_unitsUnit

Any base units corresponding to unit_type

scopesim.utils.find_file(filename, path=None, silent=False)

Find a file in search path

Parameters:

filenamestr

name of a file to look for

pathlist

list of directories to search (default: [‘./’])

silentbool

if True, remain silent when file is not found

Returns:

Absolute path of the file

scopesim.utils.from_currsys(item)

Returns the current value of a bang-string from rc.__currsys__

scopesim.utils.get_fits_type(filename)

scopesim.utils.get_meta_quantity(meta_dict, name, fallback_unit='')

Extract a Quantity from a dictionary

Parameters:

meta_dictdict

namestr

fallback_unitQuantity

Returns:

quantQuantity

scopesim.utils.has_needed_keywords(header, suffix='')

Check to see if the WCS keywords are in the header

scopesim.utils.insert_into_ordereddict(dic, new_entry, pos)

scopesim.utils.interp2(x_new, x_orig, y_orig)

Checks and corrects for decreasing x_orig values

scopesim.utils.is_fits(filename)

scopesim.utils.moffat(r, alpha, beta)

!!Unfinished!! Return a Moffat function

Parameters:

r

alpha

beta

Returns:

eta

scopesim.utils.msg(cmds, message, level=3)

Prints a message based on the level of verbosity given in cmds

Parameters:

cmdsUserCommands

just for the SIM_VERBOSE and SIM_MESSAGE_LEVEL keywords

messagestr

message to be printed

levelint, optional

all messages with level <= SIM_MESSAGE_LEVEL are printed. I.e. level=5 messages are not important, level=1 are very important

scopesim.utils.nearest(arr, val)

Return the index of the value from ‘arr’ which is closest to ‘val’

Parameters:

arrnp.ndarray, list, tuple

Array to be searched

valfloat, int

Value to find in arr

Returns:

iint

index of array where the nearest value to val is

scopesim.utils.parallactic_angle(ha, de, lat=-24.589167)

Compute the parallactic angle

Parameters:

hafloat

[hours] hour angle of target point

defloat

[deg] declination of target point

latfloat

[deg] latitude of observatory, defaults to Armazones

Returns:

parangfloat

The parallactic angle

Notes

The parallactic angle is defined as the angle PTZ, where P is the .. math:: taneta = frac{cosphisin H}{sinphi cosdelta - cosphi sindelta cos H} It is negative (positive) if the target point is east (west) of the meridian.

References

18. Ball: “A Treatise on Spherical Astronomy”, Cambridge 1908

scopesim.utils.poissonify(arr)

Add a realisation of the poisson process to the array ‘arr’.

Parameters:

arrnp.ndarray

The input array which needs a Poisson distribution applied to items

Returns:

arrnp.ndarray

The input array, but with every pixel altered according to a poisson distribution

scopesim.utils.power_vector(val, degree)

Return the vector of powers of val up to a degree

scopesim.utils.pretty_print_dict(dic, indent=0)

scopesim.utils.quantify(item, unit)

Ensure an item is a Quantity

Parameters:

itemint, float, array, list, Quantity

unitstr, Unit

Returns:

quantQuantity

scopesim.utils.quantity_from_table(colname, table, default_unit='')

scopesim.utils.rad2deg(theta)

scopesim.utils.real_colname(name, colnames, silent=True)

scopesim.utils.return_latest_github_actions_jobs_status(owner_name='AstarVienna', repo_name='ScopeSim', branch='dev_master', actions_yaml_name='tests.yml')

Gets the status of the latest test run

scopesim.utils.seq(start, stop, step=1)

Replacement for numpy.arange modelled after R’s seq function

Returns an evenly spaced sequence from start to stop. stop is included if the difference between start and stop is an integer multiple of step.

From the documentation of numpy.range: “When using a non-integer step, such as 0.1, the results will often not be consistent.” This replacement aims to avoid these inconsistencies.

Parameters:

start, stop: [int, float]

the starting and (maximal) end values of the sequence.

step[int, float]

increment of the sequence, defaults to 1

scopesim.utils.set_logger_level(which='console', level='ERROR')

Sets the level of logging for either the console or file logger

Parameters:

whichstr

[“console”, “file”]

levelstr

[“ON”, “OFF”, “DEBUG”, “INFO”, “WARN”, “ERROR”, “CRITICAL”]

scopesim.utils.setup_loggers(**kwargs)

Sets up both console and file loggers.

Acceptable parameters are the same as the !SIM.logging sub dictionary

scopesim.utils.stringify_dict(dic, ignore_types=(<class 'str'>, <class 'int'>, <class 'float'>))

Turns a dict entries into strings for addition to FITS headers

scopesim.utils.telescope_diffraction_limit(aperture_size, wavelength, distance=None)

Returns the diffraction limit of a telescope

Parameters:

aperture_sizefloat

[m] The diameter of the primary mirror

wavelengthfloat

[um] The wavelength for diffarction

distancefloat, optional

Default is None. If distance is given, the transverse distance for the diffraction limit is returned in the same units as distance

Returns:

diff_limitfloat

[arcsec] The angular diffraction limit. If distance is not None, diff_limit is in the same units as distance

scopesim.utils.transverse_distance(angle, distance)

Turn an angular distance into a proper transverse distance

Parameters:

anglefloat

[arcsec] The on-sky angle

distancefloat

The distance to the object. Units are arbitary

Returns:

trans_distancefloat

proper transverse distance. Has the same Units as distance

scopesim.utils.unify(x, unit, length=1)

Convert all types of input to an astropy array/unit pair

Parameters:

xint, float, np.ndarray, astropy.Quantity

The array to be turned into an astropy.Quantity

unitastropy.Quantity

The units to attach to the array

lengthint, optional

If x is a scalar, and the desired output is an array with length

Returns:

yastropy.Quantity

scopesim.utils.unit_from_table(colname, table, default_unit='')

Looks for the unit for a column based on the meta dict keyword “<col>_unit”

scopesim.utils.write_report(text, filename=None, output=['rst'])

Writes a report string to file in latex or rst format

scopesim.utils.zendist2airmass(zendist)

Convert zenith distance to airmass

Parameters:

zenith distance[deg]

Zenith distance angle

Returns:

airmass in sec(z) approximation

scopesim.utils.zenith_dist_to_airmass(zenith_dist)

zenith_dist is in degrees

X = sec(Z)