diff options
Diffstat (limited to 'iss/predictions.py')
| -rw-r--r-- | iss/predictions.py | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/iss/predictions.py b/iss/predictions.py index 7febe62..3c05ef2 100644 --- a/iss/predictions.py +++ b/iss/predictions.py @@ -1,24 +1,30 @@ from skyfield.api import Topos, load +from .utils import chunks + class Predictions(object): ISS = "ISS (ZARYA)" - def __init__(self, lat, lng, altitude=30.0, tz="UTC", satellite=ISS): + def __init__( + self, lat, lng, altitude=30.0, tz="UTC", satellite=ISS, start=None, days=10 + ): self.lat = lat self.lng = lng self.altitude = altitude self.tz = tz self.satellite = satellite + self.start = start + self.days = days def init_stations(self): stations_url = "http://celestrak.com/NORAD/elements/stations.txt" return load.tle_file(stations_url) - def get_next_days(self, days=10): + def get_next_days(self): ts = load.timescale() - t0 = ts.now() - t1 = ts.ut1_jd(t0.ut1 + days) + t0 = ts.now() if not self.start else ts.ut1_jd(self.start) + t1 = ts.ut1_jd(t0.ut1 + self.days) return t0, t1 def get_location(self): @@ -31,13 +37,17 @@ class Predictions(object): def get_predictions(self): satellite = self.get_satellite() - t0, t1 = self.get_next_days(days=10) + t0, t1 = self.get_next_days() location = self.get_location() - t, events = satellite.find_events( + ts, _events = satellite.find_events( location, t0, t1, altitude_degrees=self.altitude ) - for ti, event in zip(t, events): - name = ("rise above 30°", "culminate", "set below 30°")[event] - print(ti.utc_strftime("%Y %b %d %H:%M:%S"), name) + # events are returned as 3-tuples of (rise, culminate, set) + # where rise/set are relative to given altitude + # docs mention the possibilibity of several culminations + # https://rhodesmill.org/skyfield/earth-satellites.html#finding-when-a-satellite-rises-and-sets + # but this doesn't seem to happen in our case + preds = chunks(ts, 3) + return [[t.utc_iso() for t in p] for p in preds] |