sorcha.modules.PPMiniDifi

Functions

haversine_np(lon1, lat1, lon2, lat2)

Calculate the great circle distance between two points

hasTracklet(mjd, ra, dec, maxdt_minutes, ...)

Given a set of observations in one night, calculate it has

trackletsInNights(night, mjd, ra, dec, maxdt_minutes, ...)

Calculate, for a given set of observations sorted by observation time,

discoveryOpportunities(nights, nightHasTracklets, ...)

Find all nights where a trailing window of <window> nights (including the

linkObject(obsv, seed, maxdt_minutes, minlen_arcsec, ...)

For a set of observations of a single object, calculate if there are any tracklets,

linkObservations(obsv, seed[, objectId, sourceId, ...])

Ingesting a set of observations for one or more objects, determine if each object

Module Contents

haversine_np(lon1, lat1, lon2, lat2)[source]

Calculate the great circle distance between two points on the earth (specified in decimal degrees)

Parameters:

  • lon1 (float or array of floats) -- longitude of point 1

  • lat1 (float or array of floats) -- latitude of point 1

  • lon2 (float or array of floats) -- longitude of point 2

  • lat2 (float or array of floats) -- latitude of point 2

Returns:

  • float or array of floats

  • Great distance between the two points [Units (Decimal degrees])

Notes

All args must be of equal length.

Because SkyCoord is slow AF.

hasTracklet(mjd, ra, dec, maxdt_minutes, minlen_arcsec, min_observations)[source]

Given a set of observations in one night, calculate it has at least onedetectable tracklet.

Parameters:

  • mjd (float or array of floats) -- Modified Julian date time

  • ra (float or array of floats) -- Object's RA at given mjd [Units: degrees]

  • dec (float or array of floats) -- Object's dec at given mjd [Units: degrees]

  • maxdt_minutes (float) -- Maximum allowable time between observations [Units: minutes]

  • minlen_arcsec (float) -- Minimum allowable distance separation between observations [Units: arcsec]

  • (int) (min_observations) -- the minimum number of observations in a night required to form a tracklet.

Returns:

  • boolean

  • True if tracklet can be made else False

trackletsInNights(night, mjd, ra, dec, maxdt_minutes, minlen_arcsec, min_observations)[source]

Calculate, for a given set of observations sorted by observation time, whether or not it has at least one discoverable tracklet in each night.

Parameters:

  • night (float or array of floats) -- Array of the integer night corresponding to each observation

  • mjd (float or array of floats) -- Modified Julian date time

  • ra (float or array of floats) -- Object's RA at given mjd [Units: degrees]

  • dec (float or array of floats) -- Object's dec at given mjd [Units: degrees]

  • maxdt_minutes (float) -- Maximum allowable time between observations [Units: minutes]

  • minlen_arcsec (float) -- Minimum allowable distance separation between observations [Units: arcsec]

  • (int) (min_observations) -- the minimum number of observations in a night required to form a tracklet.

Returns:

  • nights (float or array of floats) -- Numpy array of the unique nights in the set of observations

  • hasTrk (boolean or array of booleans) -- Array denoting if each night has a discoverable tracklet

discoveryOpportunities(nights, nightHasTracklets, window, nlink, p, rng)[source]

Find all nights where a trailing window of <window> nights (including the current night) has at least <nlink> tracklets to constitute a discovery.

Parameters:

  • nights (float or array of floats) -- Array of the integer night corresponding to each observation

  • nightHasTracklets (list of booleans) -- List of nights that have tracklets within them

  • window (float) -- Number of tracklets required with <= this window to complete a detection

  • nlink (float) -- Number of tracklets required to form detection

  • p (float) -- SSP detection efficiency, or what fraction of objects are successfuly linked

  • rng (numpy RNG generator object) -- PGC64 generator object to determine which objects to drop

Returns:

  • discIdx (float) -- The index of where in the observation array the object is reported as discovered

  • disc (list of floats) -- List of MJD dates where the object is discoverable

linkObject(obsv, seed, maxdt_minutes, minlen_arcsec, min_observations, window, nlink, p, night_start_utc_days)[source]

For a set of observations of a single object, calculate if there are any tracklets, if there are enough tracklets to form a discovery window, and then report back all of those successful discoveries.

Parameters:

  • obsv (numpy array) --

    Array of observations for one object, of the format: ssObjectId : str

    Unique ID for the Solar System object

    diaSourceIdfloat

    Unique ID for the observation

    midPointTaifloat

    Time for the observation midpoint (MJD)

    rafloat

    RA of the object (J2000)

    declfloat

    Declination of the object (J2000)

  • seed (float) -- Initial seed per object to keep observations deterministic for multithreading

  • maxdt_minutes (float) -- Maximum allowable time between observations [Units: minutes]

  • minlen_arcsec (float) -- Minimum allowable distance separation between observations [Units: arcsec]

  • (int) (min_observations) -- the minimum number of observations in a night required to form a tracklet.

  • window (float) -- Number of tracklets required with <= this window to complete a detection

  • nlink (float) -- Number of tracklets required to form detection

  • p (float) -- SSP detection efficiency, or what fraction of objects are successfuly linked

  • night_start_utc_days (float) -- The UTC time of local noon at the observatory

Returns:

  • discoveryObservationId (float) -- The ID of the observation that triggered the successful linking

  • discoverySubmissionDate (float) -- The night at which the discovery is first submitted

  • discoveryChances (float) -- The number of chances for discovery of the object

linkObservations(obsv, seed, objectId='ssObjectId', sourceId='diaSourceId', mjdTime='midPointTai', ra='ra', dec='decl', **config)[source]

Ingesting a set of observations for one or more objects, determine if each object would be discovered by the SSP pipeline based on tracklet forming and linking.

Parameters:

  • obsv (numpy array) --

    Array of observations for each object, of the format: ssObjectId : str

    Unique ID for the Solar System object

    diaSourceIdfloat

    Unique ID for the observation

    midPointTaifloat

    Time for the observation midpoint (MJD)

    rafloat

    RA of the object (J2000)

    declfloat

    Declination of the object (J2000)

  • seed (float) -- Initial seed per object to keep observations deterministic for multithreading

  • objectId (string, default="ssObjectId") -- Column name for object ID's in observations dataframe

  • sourceId (string, default="diaSourceId") -- Column name for observation ID's in observations dataframe

  • mjdTime (string, default="midPointTai") -- Column name for MJD's in observations dataframe

  • ra (string, default=ra") -- Column name for object RA's in observations dataframe

  • dec (string, default="decl") -- Column name for object Dec's in observations dataframe

  • **config -- Dictionary containing configuration file variables

Returns:

obj --

Array with one row per detected object, of the format:
ssObjectIdstr

Unique ID for the Solar System object

discoveryObservationIdfloat

Unique ID for the observation

discoverySubmissionDatefloat

The night at which the discovery is first submitted

discoveryChancesfloat

The number of chances for discovery of the object

Return type:

numpy array