Editing HackASat2020 (section)

=Challenges=
==Astronomy, Astrophysics, Astrometry, Astrodynamics, AAAA==
===I Like to Watch===
====Challenge Info====
<pre>
We've captured data from a satellite that shows a flag located at the base of the Washington Monument.
The image was taken on March 26th, 2020, at 21:54:29
The satellite we used was:

REDACT
1 13337U 98067A   20087.38052801 -.00000452  00000-0  00000+0 0  9995
2 13337  51.6460  33.2488 0005270  61.9928  83.3154 15.48919755219337

Use a Google Earth Pro KML file to 'Link' to http://18.191.77.141:6723/cgi-bin/HSCKML.py
and 'LookAt' that spot from where the satellite when it took the photo and get us that flag!</pre>
====Notes====
* TLE Coordinates
* Need [https://static.2020.hackasat.com/a5c679be9509cfdf096add229e84422124804d3a/example.zip this file]
* Need to use Skyfield for Python 
* Washington Monument is at -77.03527 Longitude and 38.88948 Latitude

====Scripts====
* Get Satellite Location at Time
<pre>
from skyfield.api import EarthSatellite, load

ts = load.timescale()
line1 = "1 13337U 98067A   20087.38052801 -.00000452  00000-0  00000+0 0  9995"
line2 = "2 13337  51.6460  33.2488 0005270  61.9928  83.3154 15.48919755219337"
satellite = EarthSatellite(line1, line2, 'REDACT', ts)

t = ts.utc(2020, 3, 26, 21, 54, 29)
geocentric = satellite.at(t)
print(geocentric.position.km)

subpoint = geocentric.subpoint()
print('Latitude:', subpoint.latitude)
print('Longitude:', subpoint.longitude)
print('Elevation (m):', int(subpoint.elevation.m))
</pre>
* Something
<pre>
from skyfield.api import EarthSatellite, Topos, load

ts = load.timescale()
t = ts.utc(2020, 3, 26, 21, 54, 29)

line1 = "1 13337U 98067A   20087.38052801 -.00000452  00000-0  00000+0 0  9995"
line2 = "2 13337  51.6460  33.2488 0005270  61.9928  83.3154 15.48919755219337"

monument = Topos(latitude='38.8894 N', longitude='77.0352 W')
satellite = EarthSatellite(line1, line2, name='REDACT')

geometry = satellite.at(t)

subpoint = geometry.subpoint()
latitude = subpoint.latitude
longitude = subpoint.longitude
elevation = subpoint.elevation

difference = satellite - monument
geometry = difference.at(t)

print(difference)
print('--------------')

alt, az, distance = geometry.altaz()
print('alt: ', alt)
print('az: ', az)
print(int(distance.m), 'm')
</pre>
====References====
* https://developers.google.com/kml/documentation/cameras
* https://rhodesmill.org/skyfield/earth-satellites.html
* https://rhodesmill.org/skyfield/positions.html