def getAntitransitTime( body, location, date ):
if isinstance( location, str ):
location = getLocation( location )
if not isinstance( body, ephem.Body ) or not isinstance( location, RPNLocation ) or \
not isinstance( date, RPNDateTime ):
raise ValueError( 'expected an astronomical object, a locaton and a date-time' )
location.observer.date = date.to( 'utc' ).format( )
location.observer.horizon = '0'
ephemSetting = location.observer.next_setting( body )
setting = RPNDateTime.convertFromEphemDate( ephemSetting ).getLocalTime( )
rising = RPNDateTime.convertFromEphemDate( location.observer.next_rising( body, start=ephemSetting ) ).getLocalTime( )
return subtract( rising, setting )
def getPreviousSetting( body, location, date ):
if isinstance( location, str ):
location = getLocation( location )
if not isinstance( body, ephem.Body ) or not isinstance( location, RPNLocation ) or not isinstance( date, RPNDateTime ):
raise ValueError( 'expected an astronomical object, a locaton and a date-time' )
old_horizon = location.observer.horizon
location.observer.date = date.to( 'utc' ).format( )
location.observer.horizon = '0'
result = RPNDateTime.convertFromEphemDate( location.observer.previous_setting( body ) ).getLocalTime( )
location.observer.horizon = old_horizon
return result
def getNextDusk( location, date, horizon = -6 ):
if isinstance( location, str ):
location = getLocation( location )
if not isinstance( location, RPNLocation ) or not isinstance( date, RPNDateTime ):
raise ValueError( 'expected locaton and date-time arguments' )
old_horizon = location.observer.horizon
location.observer.date = date.to( 'utc' ).format( )
location.observer.horizon = str( horizon )
result = RPNDateTime.convertFromEphemDate(
location.observer.next_setting( ephem.Sun( ), use_center=True ) ).getLocalTime( )
location.observer.horizon = old_horizon
return result
