Filling in Degrees in a Circle (Astronomy)

W. eWatson notvalid2 at sbcglobal.net
Fri Aug 22 19:12:48 EDT 2008


The other night I surveyed a site for astronomical use by measuring the 
altitude (0-90 degrees above the horizon) and az (azimuth, 0 degrees north 
clockwise around the site to 360 degrees, almost north again) of obstacles, 
trees. My purpose was to feed this profile of obstacles (trees) to an 
astronomy program that would then account for not sighting objects below the 
trees.

When I got around to entering them into the program by a file, I found it 
required the alt at 360 azimuth points in order from 0 to 360 (same as 0). 
Instead I have about 25 points, and expected the program to be able to do 
simple linear interpolation between those.

Is there some simple operational device in Python that would allow me to 
create an array (vector) of 360 points from my data by interpolating between 
azimuth points when necessary? All my data I rounded to the nearest integer. 
Maybe there's an interpolation operator?

As an example, supposed I had made 3 observations: (0,0) (180,45) and 
(360,0). I would want some thing like (note the slope of the line from 0 to 
179 is 45/180 or 0.25):
alt: 0, 0.25, 0.50, 0.75, ... 44.75, 45.0
az : 0, 1,    2,    3,              180

Of course, I don't need the az.

-- 
            Wayne Watson (Watson Adventures, Prop., Nevada City, CA)

              (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
               Obz Site:  39° 15' 7" N, 121° 2' 32" W, 2700 feet

                     Web Page: <www.speckledwithstars.net/>



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