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CL_gm_betaEclipse

Eclipse interval for circular or elliptical orbits.

Calling Sequence

[half_span, mid_pos] = CL_gm_betaEclipse(sma, betaa [[, ecc, argsp, er]])

Description

Parameters

sma:

Semi major axis [m] (1xN or 1x1)

betaa:

Sun beta angle (can be positive or negative) [rad] (1xN or 1x1)

ecc:

(optional) Eccentricity. Default value is 0. (1xN or 1x1)

argsp:

(optional) Angle between the Sun direction and the periapsis in the orbit plane. Same sign convention as for the argument of periapsis. Default value is 0. (1xN or 1x1)

er:

(optional) Planet radius (default is %CL_eqRad) [m] (1xN or 1x1)

half_span:

Eclipse interval half-length (in true anomaly) [rad] (1xN)

mid_pos:

Angle from the Sun direction in the orbit plane defining the middle of the eclipse interval [rad] (1xN)

See also

Authors

Examples

// Example 1
betaa = CL_deg2rad([10, 20]);
sma = 7.e6;
CL_gm_betaEclipse(sma, betaa)
CL_gm_betaEclipse(sma, betaa, 0) // same

// Example 2
cjd = 20050;
// orbital elements (sma, ecc, inc, arg of perigee, RAAN)
sma = 10000.e3;
ecc = 0.01;
inc = CL_deg2rad(98.7);
argp = %pi/2;
raan = %pi/4;
// Sun right ascension and declination
// => beta angle, orbital noon and argsp (= Sun -> perigee)
pos_sun_sph = CL_co_car2sph(CL_eph_sun(cjd));
alpha_sun = pos_sun_sph(1);
delta_sun = pos_sun_sph(2);
betaa = CL_gm_raan2beta(inc, raan, alpha_sun, delta_sun);
pso_noon = CL_gm_orbitalNoon(inc, raan, alpha_sun, delta_sun);
argsp = argp - pso_noon;
// Results (true anomaly of start/end of eclipse)
[half_span, mid_pos] = CL_gm_betaEclipse(sma, betaa, ecc, argsp);
anv_start = mid_pos - argsp - half_span
anv_end = mid_pos - argsp + half_span

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