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This commit is contained in:
Timur A. Fatkhullin 2025-04-29 00:11:51 +03:00
parent fd105277b9
commit 18628aff28
2 changed files with 79 additions and 2 deletions
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6
cxx/mcc_coord.h
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@ -260,7 +260,8 @@ public:
auto operator==(const MccAngle& other) const
{
return _angleInRads == other._angleInRads;
return utils::isEqual(_angleInRads, other._angleInRads);
// return _angleInRads == other._angleInRads;
}
auto operator<=>(double other) const
@ -270,7 +271,8 @@ public:
auto operator==(double other) const
{
return _angleInRads == other;
return utils::isEqual(_angleInRads, other);
// return _angleInRads == other;
}
};

75
cxx/mount_astrom.h
View File

@ -167,6 +167,9 @@ static int mcc_julday(traits::mcc_systime_c auto const& start_time,
* the function returns a std::pair:
* .first = time duration to reach given altitude BEFORE object upper culmination
* .second = time duration to reach given altitude AFTER object upper culmination
*
*
* input RA and DEC are apparent!
*/
std::pair<std::chrono::duration<double>, std::chrono::duration<double>> mcc_time_to_alt(
const MccAngle& alt,
@ -370,6 +373,78 @@ double mcc_time_to_alt_limit(traits::mcc_real_or_char_range auto const& alt_limi
*/
/*
* Computes a time duration to reach given azimuth
*
* the function returns a std::pair:
* .first = time duration to reach given altitude BEFORE object upper culmination
* .second = time duration to reach given altitude AFTER object upper culmination
*
*
* input RA and DEC are apparent!
* input azimuth is assumed to be started from the South through the West
* (the South is az = 0, the West is az = pi/2 ...)
*/
std::pair<std::chrono::duration<double>, std::chrono::duration<double>> mcc_time_to_az(
const MccAngle& az,
const MccAngle& ra,
const MccAngle& dec,
const MccAngle& lat,
const MccAngle& lon,
traits::mcc_systime_c auto const& now,
traits::mcc_time_duration_c auto const& dut1, // UT1-UTC
traits::mcc_time_duration_c auto const& tt_tai, // TT-TAI
// TAI-UTC (leap seconds)
traits::mcc_time_duration_c auto const& tai_utc)
{
auto nan_dur = std::chrono::duration<double>(std::numeric_limits<double>::quiet_NaN());
auto inf_dur = std::chrono::duration<double>(std::numeric_limits<double>::infinity());
auto cs_d = cos(dec);
auto cos_az = cos(az);
auto C1 = cs_d / tan(az);
auto C2 = -sin(dec) * cos(lat);
auto C3 = cs_d * sin(lat);
auto C2C3 = C2 * C3;
auto C1_2 = C1 * C1;
auto C2_2 = C2 * C2;
auto C3_2 = C2 * C3;
auto C1C3 = C1_2 + C3_2;
auto D = C2_2 * C3_2 - C1C3 * (C2_2 - C1_2);
if (D < 0.0) {
return {inf_dur, inf_dur};
}
auto cos_t1 = -(C2C3 + sqrt(D)) / C1C3;
auto cos_t2 = -(C2C3 - sqrt(D)) / C1C3;
auto sin_z1 = (C2 + C3 * cos_t1) / cos_az;
auto sin_z2 = (C2 + C3 * cos_t2) / cos_az;
auto ut1 = now + dut1;
auto tt = now + tai_utc + tt_tai;
double ut1_mjd, tt_mjd;
int ret = mcc_julday(ut1, ut1_mjd);
if (ret) {
return {nan_dur, nan_dur};
}
ret = mcc_julday(tt, tt_mjd);
if (ret) {
return {nan_dur, nan_dur};
}
double lst_now = erfa::eraGst06a(ERFA_DJM0, ut1_mjd, ERFA_DJM0, tt_mjd);
lst_now += lon;
}
/* Classes to represent IERS bulletins
*
* BULLETIN A: https://datacenter.iers.org/data/latestVersion/bulletinA.txt