ObservationMetaData

class rubin_sim.utils.ObservationMetaData(bound_type=None, bound_length=None, mjd=None, pointing_ra=None, pointing_dec=None, rot_sky_pos=None, bandpass_name=None, site=<rubin_sim.utils.site.Site object>, m5=None, sky_brightness=None, seeing=None)

Bases: object

Track metadata for a given telescope pointing.

This class contains any metadata for a query which is associated with a particular telescope pointing, including bounds in RA and DEC, and the time of the observation.

Parameters:

pointingfloat, opt

[RA,Dec] float The coordinates of the pointing (in degrees; in the International Celestial Reference System)

bound_typestr, opt

characterizes the shape of the field of view. Current options are ‘box, and ‘circle’

bound_lengthfloat or np.ndarray, opt

is the characteristic length scale of the field of view in degrees. If bound_type is ‘box’, bound_length can be a float (in which case bound_length is half the length of the side of each box) or bound_length can be a numpy array in which case the first argument is half the width of the RA side of the box and the second argument is half the Dec side of the box. If bound_type is ‘circle,’ this will be the radius of the circle. The bound will be centered on the point (pointing_ra, pointing_dec), however, because objects are stored at their mean RA, Dec in the LSST databases (i.e. they are stored at values of RA, Dec which neglect proper motion), the bounds applied to database queries will be made slightly larger so that queries can be reasonably expected to return all of the objects within the desired field of view once those corrections have been applied.

mjdfloat, opt

Either a float (in which case, it will be assumed to be in International Atomic Time), or an instantiation of the ModifiedJulianDate class representing the date of the observation

bandpass_namestr or list of str, opt

a char (e.g. ‘u’) or list (e.g. [‘u’, ‘g’, ‘z’]) denoting the bandpasses used for this particular observation

siterubin_sim.utils.Site, opt

an instantiation of the rubin_sim.utils.Site class characterizing the site of the observatory.

m5float or list of `float, opt

this should be the 5-sigma limiting magnitude in the bandpass or bandpasses specified in bandpass_name. Ultimately, m5 will be stored in a dict keyed to the bandpass_name (or Names) you passed in, i.e. you will be able to access m5 from outside of this class using, for example: myObservationMetaData.m5[‘u’]

sky_brightnessfloat, opt

the magnitude of the sky in the filter specified by bandpass_name

seeingfloat or list of `float, opt

Analogous to m5, corresponds to the seeing in arcseconds in the bandpasses in bandpass_name

rot_sky_posfloat, opt

The orientation of the telescope in degrees. The convention for rot_sky_pos is as follows: rot_sky_pos = 0 means north is in the +y direction on the focal plane and east is +x rot_sky_pos = 90 means north is +x and east is -y rot_sky_pos = -90 means north is -x and east is +y rot_sky_pos = 180 means north is -y and east is -x This should be consistent with PhoSim conventions.

Examples

`>>> data = ObservationMetaData(bound_type='box', pointing_ra=5.0, pointing_dec=15.0, bound_length=5.0)`

Attributes Summary

bandpass	The bandpass associated with this ObservationMetaData.
bound_length	Either a list or a float indicating the size of the field of view associated with this ObservationMetaData.
bound_type	Tag indicating what sub-class of SpatialBounds should be instantiated for this ObservationMetaData.
bounds	Instantiation of a sub-class of SpatialBounds.
m5	A dict of m5 (the 5-sigma limiting magnitude) values associated with the bandpasses represented by this ObservationMetaData.
mjd	The MJD of the observation associated with this ObservationMetaData.
pointing_dec	The Dec of the telescope pointing in degrees (in the International Celestial Reference System).
pointing_ra	The RA of the telescope pointing in degrees (in the International Celestial Reference System).
rot_sky_pos	The rotation of the telescope with respect to the sky in degrees.
seeing	A dict of seeing values in arcseconds associated with the bandpasses represented by this ObservationMetaData
sim_meta_data	A dict of all of the columns taken from OpSim when constructing this ObservationMetaData
site	An instantiation of the Site class containing information about the telescope site.
sky_brightness	The sky brightness in mags per square arcsecond associated with this ObservationMetaData.
summary

Methods Summary

set_bandpass_m5and_seeing([bandpass_name, ...])

Set the bandpasses and associated 5-sigma limiting magnitudes and seeing values for this ObservationMetaData.

Attributes Documentation

bandpass

The bandpass associated with this ObservationMetaData. Can be a list.

bound_length

Either a list or a float indicating the size of the field of view associated with this ObservationMetaData.

See the documentation in the SpatialBounds class for more details (specifically, the ‘length’ Parameter).

In degrees (Yes: the documentation in SpatialBounds says that the length should be in radians. The present class converts from degrees to radians before passing to SpatialBounds).

bound_type

Tag indicating what sub-class of SpatialBounds should be instantiated for this ObservationMetaData.

bounds

Instantiation of a sub-class of SpatialBounds. This is what actually construct the WHERE clause of the SQL query associated with this ObservationMetaData.

m5

A dict of m5 (the 5-sigma limiting magnitude) values associated with the bandpasses represented by this ObservationMetaData.

mjd

The MJD of the observation associated with this ObservationMetaData.

pointing_dec

The Dec of the telescope pointing in degrees (in the International Celestial Reference System).

pointing_ra

The RA of the telescope pointing in degrees (in the International Celestial Reference System).

rot_sky_pos

The rotation of the telescope with respect to the sky in degrees. It is a parameter you should get from OpSim.

seeing

A dict of seeing values in arcseconds associated with the bandpasses represented by this ObservationMetaData

sim_meta_data

A dict of all of the columns taken from OpSim when constructing this ObservationMetaData

site

An instantiation of the Site class containing information about the telescope site.

sky_brightness

The sky brightness in mags per square arcsecond associated with this ObservationMetaData.

summary

Methods Documentation

set_bandpass_m5and_seeing(bandpass_name=None, m5=None, seeing=None)

Set the bandpasses and associated 5-sigma limiting magnitudes and seeing values for this ObservationMetaData.

@param [in] bandpass_name is either a char or a list of chars denoting the name of the bandpass associated with this ObservationMetaData.

@param [in] m5 is the 5-sigma-limiting magnitude(s) associated with bandpass_name

@param [in] seeing is the seeing(s) in arcseconds associated with bandpass_name

Nothing is returned. This method just sets member variables of this ObservationMetaData.