def __calc_equatorialCoordinates(self):
''' calculates position in equatorial coords from ecliptic '''
import math
Jcty = self._TSMgr.time_get_julianCenturiesJ2000()
Lam_deg = self._moonCoordinates["ecl_Lon"] # Lambda
Bet_deg = self._moonCoordinates["ecl_Lat"] # Beta
Eps_deg = MH.eps_deg(Jcty) # Epsilon
sinLam = MH.sin_deg(Lam_deg)
cosLam = MH.cos_deg(Lam_deg)
sinBet = MH.sin_deg(Bet_deg)
cosBet = MH.cos_deg(Bet_deg)
sinEps = MH.sin_deg(Eps_deg)
cosEps = MH.cos_deg(Eps_deg)
# [o. Montenbruck] "Grundlagen der Ephemeridenrechnung" S.14
# cos(del)*cos(alp) = cos(bet)*cos(lam)
# cos(del)*sin(alp) = cos(eps)*cos(bet)*sin(lam) - sin(eps)*sin(bet)
# sin(del) = sin(eps)*cos(bet)*sin(lam) + cos(eps)*sin(bet)
Del_rad = math.asin( sinEps*cosBet*sinLam + cosEps*sinBet )
Del_deg = math.degrees(Del_rad)
cosDel = math.cos(Del_rad)
cosAlp = (cosBet*cosLam) / cosDel
sinAlp = (cosEps*cosBet*sinLam - sinEps*sinBet) / cosDel
Alp_deg = MH.atan2_deg(sinAlp,cosAlp)%360
self._moonCoordinates["equa_Lon"] = Alp_deg # Alpha / RA
self._moonCoordinates["equa_Lat"] = Del_deg # Delta / DE
def _calc_topoc_equator_spherical(self):
''' computes [Position Angles] and [Angular Velocities]
([Right Ascencion] and [Declination])
in [TOPOcentric Equatorial Coordinate System] of the Sat
relavtive to the telescope.
(Center = [surface position],
References: [Earth axis] / [Equatorial plane] and
the direction to the [Vernal equinox].) '''
# Berechnung is aehnlich zu GEOzentrisch spherical,
# JEDOCH ist (x,y,z) der vektor vom telescop zum satelliten
# und fuer (x',y',z') muss x',y' vom teleskop berechnet werden
# -------------
# get cartesian corrdinates
xp, yp, zp = self._topocentr_equator["cartesian"]["vel"]
x, y, z = self._topocentr_equator["cartesian"]["pos"]
r = math_helper.vector_abs((x, y, z))
# -------------
# calc spherical coordinates
# -------------
# ANGULAR POSITION
Ra = math_helper.atan2_deg(y, x)
De = math_helper.asin_deg(z / r)
self._topocentr_equator["spherical"]["pos"]["Ra"] = Ra
self._topocentr_equator["spherical"]["pos"]["De"] = De
self._topocentr_equator["spherical"]["pos"]["R"] = r
# -------------
# ANGULAR VELOCITY
# x,y,z = f(t)
# r = f(t) = sqrt(x^2+y^2+z^2)
# Ra = atan(y/x)
# d( atan(y(t)/x(t)) )/dt = (x*y' - y*x')/(x^2+y^2) in rad/s
Ra_dot = math.degrees((x * yp - y * xp) / (x**2 + y**2))
# De = asin(z/r)
# d( asin(z(t)/r(t)) )/dt =
# z' - z/(r^2) * (x*x'+y*y'+z*z')
# = ------------------------------ in rad/s
# sqrt(r^2 - z^2)
De_dot = math.degrees((zp - z / (r**2) * (x * xp + y * yp + z * zp)) /
math.sqrt(r**2 - z**2))
self._topocentr_equator["spherical"]["vel"]["Ra"] = Ra_dot
self._topocentr_equator["spherical"]["vel"]["De"] = De_dot