astroplan_woes.py

import astroplan                                                                
from astroplan import Observer, FixedTarget                                     
from astropy.coordinates import SkyCoord                                        
from astropy.time import Time, TimeDelta                                        
from astroplan.constraints import AtNightConstraint, AirmassConstraint          
import pandas as pd                                                             
import numpy as np                                                              
                                                                                
def mst2utc(time):                                                              
    ''' Converts from MST to UTC '''                                            
    dt = TimeDelta(7*3600, format='sec')                                        
    return time + dt                                                            
                                                                                
def utc2mts(time):                                                              
    ''' Converts from UTC to MST '''                                            
    dt = TimeDelta(7*3600, format='sec')                                        
    return time - dt                                                

# make telescope location                                                      
kpno = Observer.at_site('KPNO', timezone='MST')

# make target coordinates                                                      
coords = SkyCoord(131.1331774, 62.41165761, unit='deg', frame='icrs')

# make all the targets                                                         
target = [FixedTarget(name='test', coord=coords)]                   
                                                                               
# make the observing time - Local time.                                         
start_time_mst = Time('2016-11-11 18:53')                                       
end_time_mst = Time('2016-11-12 05:29')
night_time = end_time_mst - start_time_mst
observable_time_mst = start_time_mst + night_time * np.linspace(0,1,75)         
                                                                                
# convert everything to UTC                                                     
start_time_utc = mst2utc(start_time_mst)                                        
end_time_utc = mst2utc(end_time_mst)                                            
observable_time_utc = mst2utc(observable_time_mst) 

print(kpno.target_is_up(start_time_utc, target))
# expect to print True

# now we try to do all the fancy scheduling                                    
# set our only constraint to be at night                                       
constraint = [AtNightConstraint.twilight_civil(), AirmassConstraint(max=5)]    
print(astroplan.is_observable(constraint, kpno, target[:1],                   
                              time_range=observable_time_utc))  
# expect to print True.