vector calculations for apparent().altaz()

Hi Brandon, recently I heavily used the new panda approach for hipparchus catalogue. As I run through your examples they worked fine. Is used the same filter approach like in your documentation.

For getting an AltAz picture of the selected stars I would replace

ra, dec, distance = astrometric.radec()

straight forward with

alt, az, d = astrometric.apparent().altaz()

but this approach throws some errors:

File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/skyfield/positionlib.py", line 413, in apparent
    position_au, gcrs_position)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/skyfield/earthlib.py", line 115, in compute_limb_angle
    coszd = dots(position_au, observer_au) / (disobj * disobs)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/skyfield/functions.py", line 15, in dots
    return (v * u).sum(axis=0)
ValueError: operands could not be broadcast together with shapes (3,93) (3,)

From my point of view that might be related to absence of vector capabilities in apparent and altaz module. If you could confirm that, I would change my code to get a list of Stars out of the datagram like:

bright_stars = list()
for index, row in df.iterrows():
    bright_stars.append(Star.from_dataframe(row)

to get a list, which is appropriate. Any thoughts about my doing ? Many thanks in advance and merry christmas !

Michel

[mworion]

@brandon-rhodes,

Sorry for the late answer, I’m on a business trip, but got a quick test and with 1.14 is works nicely. Thanks for fixing !

Michel

[brandon-rhodes]

Great! I’ll see about getting a release out this week, if things don’t get too busy.