[AstroPy] problems with astroplan

Steven Boada boada at physics.rutgers.edu
Mon Nov 7 14:22:56 EST 2016

Hi list,

I'm headed to KPNO and I'm trying out astroplan for the first time. But 
I'm getting some confusing output. Here's an example.

from astroplan import Observer, FixedTarget
from astropy.coordinates import SkyCoord

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

# 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
start_time = Time('2016-11-11 01:54:00')
end_time = Time('2016-11-11 12:30:00')
time_delta = end_time - start_time
observable_time = start_time + time_delta * np.linspace(0,1,75)

print(kpno.target_is_up(start_time, target))
# should print True

# now we try to do all the fancy scheduling
# set our only constraint to be at night
constraint = AtNightConstraint.twilight_civil()

print(astroplan.is_observable(constraint, kpno, targets[:1], 
# should print false.

Looking up the airmass etc. on the web, the target is certainly visible 
from KPNO. I'm obviously missing something, but I can't seem to figure 
out what it is.

Thanks for your help.



Steven Boada

Postdoctoral Researcher
Rutgers University
boada at physics.rutgers.edu

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