Name

CL_gm_betaEclipse — Eclipse angular semi amplitude wrt beta angle for circular orbits.

Calling Sequence

   [semi_ang_ecl] = CL_gm_betaEclipse(sma,betaa[,er])
   
   

Description

  • Computes the angular semiamplitude of the eclipse (semi_ang_ecl) from the semi major axis sma and beta angle betaa(angle between the satellite's orbital plane and the Sun).

    If there is no eclipse, semi_ang_ecl equals 0

    This function assumes a spherical planet and a spherical orbit.

  • If you want a more precise calculation of eclipse's position on orbit, you can use CL_gm_eclipseCir
  • Last update : 04/05/2007

Parameters

sma:

semi major axis [m] (1xN)

betaa:

beta angle [rad] (1xN)

er:

(optional) earth radius (default is %CL_eqRad) [m]

semi_ang_ecl:

angular semiamplitude of the eclipse [rad] (1xN)

See also

CL_gm_eclipseCir, CL_gm_raan2beta, CL_mod_moonSunG50

Authors

CNES - DCT/SB

Examples

// Example 1
betaa=CL_deg2rad([10;20]);
sma=[%CL_eqRad+350000;%CL_eqRad+400000];
CL_gm_betaEclipse(sma,betaa)

// Example 2
cjd = 20050;
[r_sun,rs] = CL_mod_moonSunG50(cjd,'s');
r_sph = CL_co_car2sph(r_sun);
alpha_sun = r_sph(1);
delta_sun = r_sph(2);
raan = %pi/4;
inc = CL_deg2rad(98.7);
betaa = CL_gm_raan2beta(inc,raan,alpha_sun,delta_sun)

sma = 6978.e3;
semi_ang_ecl = CL_gm_betaEclipse(sma,betaa)
//mean motion J2
xnmoy = CL_op_paramsJ2('mm',sma,0,inc);
tot_duration_minutes = 2*semi_ang_ecl/xnmoy/60.0