AtNightConstraint#

class m4opt.constraints.AtNightConstraint(max_solar_altitude=<Quantity 0. deg>)[source] [edit on github]#

Bases: Constraint

Constrain observations to specific twilight phases or a user-defined solar altitude limit.

Parameters:: max_solar_altitude (Quantity) – A user-defined maximum solar altitude threshold. This parameter is required when not using specific twilight methods (twilight_civil, twilight_nautical, twilight_astronomical). It sets the maximum altitude of the Sun for which observations are allowed.

Notes

The pressure is set to zero when calculating the Sun’s altitude. This avoids errors due to atmospheric refraction at very low altitudes.

Examples

>>> from astropy.coordinates import EarthLocation, SkyCoord
>>> from astropy.time import Time
>>> from astropy import units as u
>>> from m4opt.constraints import AtNightConstraint
>>> time = Time("2017-08-17T00:41:04Z")
>>> target = SkyCoord.from_name("NGC 4993")
>>> location = EarthLocation.of_site("Rubin Observatory")
>>> constraint = AtNightConstraint.twilight_civil()
>>> constraint(observer_location=location, target_coord=target, obstime=time)
np.True_
>>> constraint = AtNightConstraint.twilight_nautical()
>>> constraint(observer_location=location, target_coord=target, obstime=time)
np.True_
>>> constraint = AtNightConstraint.twilight_astronomical()
>>> constraint(observer_location=location, target_coord=target, obstime=time)
np.True_

Methods Summary

`__call__`(observer_location, target_coord, ...)	Evaluate the constraint at a given observer location, target position, and time.
`twilight_astronomical`()	Create an `AtNightConstraint` for astronomical twilight (-18°).
`twilight_civil`()	Create an `AtNightConstraint` for civil twilight (-6°).
`twilight_nautical`()	Create an `AtNightConstraint` for nautical twilight (-12°).

Methods Documentation

__call__(observer_location, target_coord, obstime)[source] [edit on github]#: Evaluate the constraint at a given observer location, target position, and time.

classmethod twilight_astronomical()[source] [edit on github]#: Create an AtNightConstraint for astronomical twilight (-18°).

classmethod twilight_civil()[source] [edit on github]#: Create an AtNightConstraint for civil twilight (-6°).

classmethod twilight_nautical()[source] [edit on github]#: Create an AtNightConstraint for nautical twilight (-12°).