diff --git a/CMakeLists.txt b/CMakeLists.txt
index 03270bc..40b0a78 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -284,7 +284,11 @@ if(USE_BSPLINE_PCM)
 endif()
 
 if(USE_EIGEN3)
-    list(APPEND MCC_SRC include/mcc/mcc_pcm_construct.h)
+    list(
+        APPEND MCC_SRC
+        include/mcc/mcc_pcm_construct.h
+        include/mcc/mcc_pcm_fit.h
+    )
 endif()
 
 add_library(${PROJECT_NAME} INTERFACE ${MCC_SRC})
diff --git a/include/mcc/mcc_pcm_fit.h b/include/mcc/mcc_pcm_fit.h
new file mode 100644
index 0000000..b5a894d
--- /dev/null
+++ b/include/mcc/mcc_pcm_fit.h
@@ -0,0 +1,563 @@
+#pragma once
+
+
+/****************************************************************************************
+ *                                                                                      *
+ *                          MOUNT CONTROL COMPONENTS LIBRARY                            *
+ *                                                                                      *
+ *                                                                                      *
+ *                        "POINTING-CORRECTION-MODEL" FITTER                            *
+ *                                                                                      *
+ ****************************************************************************************/
+
+#include <eigen3/Eigen/Dense>
+
+#include "mcc_concepts.h"
+#include "mcc_coordinate.h"
+#include "mcc_pcm.h"
+
+
+namespace mcc::impl
+{
+
+enum class MccPCMFitterErrorCode : int {
+    ERROR_OK,
+    ERROR_INVALID_EPOCH,
+    ERROR_NOT_ENOUGH_DATA,
+    ERROR_INVALID_INDEX,
+#ifdef USE_BSPLINE_PCM
+    ERROR_INVALID_KNOTS_NUMBER,
+    ERROR_BSPLINE_FIT
+#endif
+};
+
+// error category
+
+struct MccPCMFitterErrorCategory : std::error_category {
+    MccPCMFitterErrorCategory() = default;
+
+    const char* name() const noexcept
+    {
+        return "MCC-DEFAULT-PCM-CONSTRUCTOR-ERROR-CATEGORY";
+    }
+
+    std::string message(int ec) const
+    {
+        MccPCMFitterErrorCode err = static_cast<MccPCMFitterErrorCode>(ec);
+
+        switch (err) {
+            case MccPCMFitterErrorCode::ERROR_OK:
+                return "OK";
+            case MccPCMFitterErrorCode::ERROR_INVALID_EPOCH:
+                return "invalid epoch";
+            case MccPCMFitterErrorCode::ERROR_NOT_ENOUGH_DATA:
+                return "not enough data point";
+            case MccPCMFitterErrorCode::ERROR_INVALID_INDEX:
+                return "invalid index of data point";
+#ifdef USE_BSPLINE_PCM
+            case MccPCMFitterErrorCode::ERROR_INVALID_KNOTS_NUMBER:
+                return "invalid number of B-spline knots";
+            case MccPCMFitterErrorCode::ERROR_BSPLINE_FIT:
+                return "B-spline fitting error";
+#endif
+            default:
+                return "UNKNOWN";
+        }
+    }
+
+    static const MccPCMFitterErrorCategory& get()
+    {
+        static const MccPCMFitterErrorCategory constInst;
+        return constInst;
+    }
+};
+
+
+inline std::error_code make_error_code(MccPCMFitterErrorCode ec)
+{
+    return std::error_code(static_cast<int>(ec), MccPCMFitterErrorCategory::get());
+}
+
+}  // namespace mcc::impl
+
+
+namespace std
+{
+
+template <>
+class is_error_code_enum<mcc::impl::MccPCMFitterErrorCode> : public true_type
+{
+};
+
+}  // namespace std
+
+
+
+namespace mcc::impl
+{
+
+template <MccMountType MOUNT_TYPE>
+class MccPCMFitter
+{
+public:
+    using ref_coordpair_t = std::conditional_t<mcc_is_equatorial_mount<MOUNT_TYPE>,
+                                               MccSkyHADEC_OBS,
+                                               std::conditional_t<mcc_is_altaz_mount<MOUNT_TYPE>, MccSkyAZZD, void>>;
+
+    static_assert(!std::is_void_v<ref_coordpair_t>, "UNSUPPORTED MOUNT TYPE!");
+
+    struct compute_result_t {
+        MccDefaultPCMType pcm_type;
+        MccError error{};  // final model computation error
+
+        size_t final_iter{};  // number of final iteration
+
+        std::vector<double> model_colon{}, model_colat{};  // fitting model values
+        std::vector<double> colon_res{}, colat_res{};      // target - model
+        std::vector<double> colon_weight{}, colat_weight;  // Tukey's weights
+
+#ifdef USE_BSPLINE_PCM
+        std::array<int, 4> bspline_fit_err{
+            0, 0, 0, 0};  // bivariate B-spline fitting exit code (see FITPACK)
+                          // 0 - pcmX(X,Y), 1 - pcmY(X,Y), 2 - revPcmX(COLON, COLAT), 3 - revPcmY(COLON, COLAT)
+
+        // quantities below are computed only fo pcm_type == MccDefaultPCMType::PCM_TYPE_BSPLINE
+        std::vector<double> inv_model_colon{}, inv_model_colat{};  // fitted inverse model values
+        std::vector<double> inv_colon_res{}, inv_colat_res{};      // encoder - model
+#endif
+    };
+
+    struct compute_params_t {
+        size_t max_iter{100};      // max number of iterations for robust linear regression method
+        double c{4.685};           // Tukey's parameter for robust linear regression method
+        double tolerance{1.0E-6};  // tolerance value for bivariare B-spline fitting
+    };
+
+
+    size_t numberOfPoints() const
+    {
+        return _targetCOLON.size();
+    }
+
+
+    void deletePoints()
+    {
+        _epoch.clear();
+        _targetCOLON.clear();
+        _targetCOLAT.clear();
+        _colatRES.clear();
+        _colonRES.clear();
+    }
+
+    template <mcc_coord_pair_c TAG_T, mcc_coord_pair_c HW_T>
+    MccError addPoint(TAG_T const& target_coords, HW_T const& hw_counts)
+        requires(TAG_T::pairKind == ref_coordpair_t::pairKind && HW_T::pairKind == MccCoordPairKind::COORDS_KIND_XY)
+    {
+        if (hw_counts.epoch() != target_coords.epoch()) {
+            return MccPCMFitterErrorCode::ERROR_INVALID_EPOCH;
+        }
+
+        _epoch.emplace_back(hw_counts.epoch());
+
+        // to ensure the input celestial coordinates are normalized
+        typename ref_coordpair_t::x_t ang_x{(double)target_coords.x()};
+        typename ref_coordpair_t::y_t ang_y{(double)target_coords.y()};
+
+        _targetCOLON.emplace_back((double)ang_x);
+        _targetCOLAT.emplace_back((double)ang_y);
+
+        // normalize encoder coordinates to the range of corresponding celestial ones
+
+        ang_x = (double)hw_counts.x();
+        ang_y = (double)hw_counts.y();
+        _hwX.emplace_back((double)ang_x);
+        _hwY.emplace_back((double)ang_y);
+
+        _colonRES.emplace_back(_targetCOLON.back() - _hwX.back());
+        _colatRES.emplace_back(_targetCOLAT.back() - _hwY.back());
+
+        return MccPCMFitterErrorCode::ERROR_OK;
+    }
+
+
+    MccError addPoint(mcc_skypoint_c auto const& target_coords, mcc_coord_pair_c auto const& hw_counts)
+        requires(std::decay_t<decltype(hw_counts)>::pairKind == MccCoordPairKind::COORDS_KIND_XY)
+    {
+        ref_coordpair_t cp;
+
+        cp.setEpoch(hw_counts.epoch());
+        auto err = target_coords.to(cp);
+        if (err) {
+            return mcc_deduced_err(err, MccDefaultPCMErrorCode::ERROR_CCTE);
+        }
+
+        return addPoint(cp, hw_counts);
+    }
+
+    template <typename COLON_T, typename COLAT_T>
+    MccError addPoint(COLON_T const& colon, COLAT_T const& colat, mcc_coord_pair_c auto const& hw_counts)
+        requires(std::is_arithmetic_v<COLON_T> && std::is_arithmetic_v<COLAT_T> &&
+                 (std::decay_t<decltype(hw_counts)>::pairKind == MccCoordPairKind::COORDS_KIND_XY))
+    {
+        ref_coordpair_t cp{typename ref_coordpair_t::x_t{colon}, typename ref_coordpair_t::y_t{colat},
+                           hw_counts.epoch()};
+
+        return addPoint(cp, hw_counts);
+    }
+
+
+    // something like:
+    //    auto [tag, hw, err] = getPoint(7);
+    template <mcc_coord_pair_c TAG_T, mcc_coord_pair_c HW_T>
+    std::tuple<TAG_T, HW_T, MccError> getPoint(size_t idx)
+        requires(std::same_as<typename TAG_T::x_t, typename ref_coordpair_t::x_t> &&
+                 std::same_as<typename TAG_T::y_t, typename ref_coordpair_t::y_t> &&
+                 HW_T::pairKind == MccCoordPairKind::COORDS_KIND_XY)
+    {
+        std::tuple<TAG_T, HW_T, MccError> point;
+
+        if (idx > numberOfPoints()) {
+            std::get<2>(point) = MccPCMFitterErrorCode::ERROR_INVALID_INDEX;
+        } else {
+            std::get<2>(point) = MccPCMFitterErrorCode::ERROR_OK;
+
+            std::get<0>(point).setX(_targetCOLON[idx]);
+            std::get<0>(point).setY(_targetCOLAT[idx]);
+            std::get<0>(point).setEpoch(_epoch[idx]);
+
+            std::get<1>(point).setX(_hwX[idx]);
+            std::get<1>(point).setY(_hwY[idx]);
+            std::get<1>(point).setEpoch(_epoch[idx]);
+        }
+
+        return point;
+    }
+
+protected:
+    // store coordinates in radians
+    std::vector<double> _targetCOLON{}, _targetCOLAT{}, _hwX, _hwY;
+    std::vector<double> _colonRES{}, _colatRES{};  // target - hw
+    std::vector<MccCelestialCoordEpoch> _epoch{};
+
+
+    void computeModelResi(compute_result_t& result)
+    {
+        result.colon_res.resize(numberOfPoints());
+        result.colat_res.resize(numberOfPoints());
+
+        for (size_t i = 0; i < numberOfPoints(); ++i) {
+            result.colon_res[i] = _colonRES[i] - result.model_colon[i];  // = target - model
+            result.colat_res[i] = _colatRES[i] - result.model_colat[i];  // = target - model
+        }
+
+#ifdef USE_BSPLINE_PCM
+        if (result.pcm_type == MccDefaultPCMType::PCM_TYPE_BSPLINE) {
+            result.inv_colon_res.resize(numberOfPoints());
+            result.inv_colat_res.resize(numberOfPoints());
+            for (size_t i = 0; i < numberOfPoints(); ++i) {
+                result.inv_colon_res[i] = _colonRES[i] - result.inv_model_colon[i];  // = hw - model
+                result.inv_colat_res[i] = _colatRES[i] - result.inv_model_colat[i];  // = hw - model
+            }
+        }
+#endif
+    }
+
+
+    compute_result_t bsplineFitting(MccDefaultPCM<MOUNT_TYPE>::pcm_data_t& pcm_data)
+    {
+        compute_result_t result{.pcm_type = pcm_data.type, .error = MccPCMFitterErrorCode::ERROR_OK};
+
+        // at least border knots must be given ([t_min, t_max])
+        if (pcm_data.bspline.knotsX.size() < 2 || pcm_data.bspline.knotsY.size() < 2) {
+            result.error = MccPCMFitterErrorCode::ERROR_INVALID_KNOTS_NUMBER;
+
+            return result;
+        }
+
+        double resi2x, resi2y;  // sum of fitting residuals squares
+
+        // full knot vectors: [t_min, t_min, t_min, t_min, ..., t_1, t_2, ..., t_max, t_max, t_max, t_max]
+        std::vector<double> tx(pcm_data.bspline.knotsX.size() + 6), ty(pcm_data.bspline.knotsY.size() + 6);
+
+        std::vector<double>&theta_hw = _hwY, theta_tag = _targetCOLAT, phi_hw = _hwX, phi_tag = _targetCOLON;
+        std::vector<double> theta, phi;
+
+        /*
+            WARNING:
+                FITPACK B-spline on sphere: in the fitting routines the first angle argument is THETA - co-latitude
+                coordinate and the second one is PHI - co-longitude!!!
+
+                In the fitting routines the first angle argument THETA must be in the range of [0.0, PI]
+                (while celestial declination is in the range of [-PI/2, PI/2])!!!
+                The second angle argument is the PHI and its valid range is [0, 2*PI]
+                (while celestial hour angle is assumed to be in the range of [-PI, PI])
+        */
+
+        if constexpr (std::same_as<ref_coordpair_t, MccSkyHADEC_OBS>) {
+            theta.resize(numberOfPoints());
+            phi.resize(numberOfPoints());
+            theta_hw = theta;
+            phi_hw = phi;
+
+            for (size_t i = 0; i < numberOfPoints(); ++i) {
+                theta_hw[i] = _hwY[i] + MCC_HALF_PI;
+                phi_hw[i] = _hwX[i] + std::numbers::pi;
+            }
+        }
+
+        tx[0] = tx[1] = tx[2] = pcm_data.bspline.knotsX[0];
+        tx[tx.size() - 1] = tx[tx.size() - 2] = tx[tx.size() - 3] =
+            pcm_data.bspline.knotsX[pcm_data.bspline.knotsX.size() - 1];
+
+        ty[0] = ty[1] = ty[2] = pcm_data.bspline.knotsY[0] + MCC_HALF_PI;
+        ty[ty.size() - 1] = ty[ty.size() - 2] = ty[ty.size() - 3] =
+            pcm_data.bspline.knotsY[pcm_data.bspline.knotsY.size() - 1] + MCC_HALF_PI;
+
+        for (size_t i = 0; i < pcm_data.bspline.knotsX.size(); ++i) {
+            tx[3 + i] = pcm_data.bspline.knotsX[i];
+        }
+        for (size_t i = 0; i < pcm_data.bspline.knotsY.size(); ++i) {
+            ty[3 + i] = pcm_data.bspline.knotsY[i] + MCC_HALF_PI;
+        }
+
+        size_t Ncoeffs = (tx.size() - 4) * (ty.size() - 4);
+
+        pcm_data.bspline.coeffsX.resize(Ncoeffs);
+        pcm_data.bspline.coeffsY.resize(Ncoeffs);
+
+
+        // direct (celestial = encoder + pcm)
+        result.bspline_fit_err[0] =
+            bsplines::fitpack_sphere_fit(theta_hw, phi_hw, _colonRES, 1.0, ty, tx, pcm_data.bspline.coeffsX, resi2x);
+        if (result.bspline_fit_err[0] > 0) {
+            result.error = MccPCMFitterErrorCode::ERROR_BSPLINE_FIT;
+            return result;
+        }
+
+        result.bspline_fit_err[1] =
+            bsplines::fitpack_sphere_fit(theta_hw, phi_hw, _colatRES, 1.0, ty, tx, pcm_data.bspline.coeffsY, resi2y);
+        if (result.bspline_fit_err[1] > 0) {
+            result.error = MccPCMFitterErrorCode::ERROR_BSPLINE_FIT;
+            return result;
+        }
+
+
+        bsplines::fitpack_eval_spl2d(ty, tx, pcm_data.bspline.coeffsX, theta_hw, phi_hw,
+                                     result.model_colon);  // get fitted residuals!!!
+
+        bsplines::fitpack_eval_spl2d(ty, tx, pcm_data.bspline.coeffsY, theta_hw, phi_hw,
+                                     result.model_colat);  // get fitted residuals!!!
+
+
+        if (pcm_data.type == MccDefaultPCMType::PCM_TYPE_BSPLINE) {
+            // here both direct and inverse coefficients will be calculated
+            pcm_data.inverseBspline.coeffsX.resize(Ncoeffs);
+            pcm_data.inverseBspline.coeffsY.resize(Ncoeffs);
+
+            std::vector<double> theta_tag(numberOfPoints());
+
+            // inverse (encoder = celestial + pcm)
+
+            std::vector<double> colon_res = _colonRES;
+            std::vector<double> colat_res = _colatRES;
+            if constexpr (std::same_as<ref_coordpair_t, MccSkyHADEC_OBS>) {
+                theta_tag = theta;
+                phi_tag = phi;
+            }
+
+            for (size_t i = 0; i < colat_res.size(); ++i) {
+                colon_res[i] = -colon_res[i];
+                colat_res[i] = -colat_res[i];
+
+                if constexpr (std::same_as<ref_coordpair_t, MccSkyHADEC_OBS>) {
+                    theta_tag[i] = _targetCOLAT[i] + MCC_HALF_PI;
+                    phi_tag[i] = _targetCOLON[i] + std::numbers::pi;
+                }
+            }
+
+            result.bspline_fit_err[2] = bsplines::fitpack_sphere_fit(theta_tag, phi_tag, colon_res, 1.0, ty, tx,
+                                                                     pcm_data.bspline.inverseCoeffsX, resi2x);
+            if (result.bspline_fit_err[2] > 0) {
+                result.error = MccPCMFitterErrorCode::ERROR_BSPLINE_FIT;
+                return result;
+            }
+
+            result.bspline_fit_err[3] = bsplines::fitpack_sphere_fit(theta_tag, phi_tag, colat_res, 1.0, ty, tx,
+                                                                     pcm_data.bspline.inverseCoeffsY, resi2y);
+            if (result.bspline_fit_err[3] > 0) {
+                result.error = MccPCMFitterErrorCode::ERROR_BSPLINE_FIT;
+                return result;
+            }
+
+            bsplines::fitpack_eval_spl2d(ty, tx, pcm_data.bspline.inverseCoeffsX, theta_tag, phi_tag,
+                                         result.inv_model_colon);  // get fitted residuals!!!
+
+            bsplines::fitpack_eval_spl2d(ty, tx, pcm_data.bspline.inverseCoeffsY, theta_tag, phi_tag,
+                                         result.inv_model_colat);  // get fitted residuals!!!
+        }
+
+        computeModelResi(result);
+
+        return result;
+    }
+
+
+    compute_result_t robustLinearRegress(MccDefaultPCM<MOUNT_TYPE>::pcm_data_t& pcm_data,
+                                         compute_params_t const& comp_params)
+    {
+        auto tukey_weight = [](Eigen::VectorXd const& resi, double tukey_c, Eigen::VectorXd& tukey_weight) {
+            Eigen::ArrayXd u = (resi / tukey_c).cwiseAbs();
+            auto mask = (u < 1.0);
+
+            Eigen::VectorXd r = mask.select(1.0 - u * u, 0.0);
+
+            tukey_weight = r.array() * r.array();
+        };
+
+        auto gastwirth_est = [](Eigen::VectorXd const& r) {
+            // auto gastwirth_est = [](Eigen::VectorXd const& resi) {
+            auto resi = r;
+            std::nth_element(resi.begin(), resi.begin() + resi.size() / 2, resi.end());
+            double md = resi(resi.size() / 2);
+            resi = resi.array() - md;
+
+            // Gastwirth’s estimation: 0.3*Q(1/3) + 0.4*Q(1/2) + 0.3*Q(2/3)
+
+            Eigen::ArrayXd arr = resi.cwiseAbs();
+
+            std::nth_element(arr.begin(), arr.begin() + 2 * arr.size() / 3, arr.end());
+
+            // add 1.0E-8 to avoid 0.0
+            return (0.3 * arr(arr.size() / 3) + 0.4 * arr(arr.size() / 2) + 0.3 * arr(2 * arr.size() / 3)) / 0.6745 +
+                   1.0E-8;
+
+            // std::nth_element(arr.begin(), arr.begin() + arr.size() / 2, arr.end());
+
+            // return arr(arr.size() / 2) / 0.6745 + 1.0E-8;
+        };
+
+        compute_result_t result{.pcm_type = pcm_data.type, .error = MccPCMFitterErrorCode::ERROR_OK};
+
+        const size_t n_coeffs = MOUNT_TYPE == MccMountType::FORK_TYPE ? 9 : 8;
+
+        Eigen::MatrixXd X(2 * numberOfPoints(), n_coeffs);
+        Eigen::VectorXd y(2 * numberOfPoints()), beta = Eigen::VectorXd::Zero(n_coeffs), new_beta(n_coeffs);
+        Eigen::VectorXd model;
+
+        Eigen::RowVectorXd row(n_coeffs);
+        double tgY, sinY, cosY, rcosY, cosX, sinX, cosPhi = std::cos(pcm_data.siteLatitude),
+                                                   sinPhi = std::sin(pcm_data.siteLatitude);
+
+        // system matrix and right-hand vector
+        for (size_t i = 0; i < numberOfPoints(); ++i) {
+            cosY = std::cos(_targetCOLAT[i]);
+            sinY = std::sin(_targetCOLAT[i]);
+            rcosY = 1.0 / cosY;
+            tgY = std::tan(_targetCOLAT[i]);
+            cosX = std::cos(_targetCOLON[i]);
+            sinX = std::sin(_targetCOLON[i]);
+
+
+            // [X0, Y0, collim, nonperp, misal1, misal2, tubefl, DECaxfl, forkfl] or
+            // [X0, Y0, collim, nonperp, misal1, misal2, tubefl, DECaxfl]
+            if constexpr (MOUNT_TYPE == MccMountType::FORK_TYPE) {
+                if (utils::isEqual(cosY, 0.0)) {
+                    row << 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0;
+                } else {
+                    row << 1.0, 0.0, rcosY, tgY, -cosX * tgY, sinX * tgY, cosPhi * sinX * rcosY,
+                        -(cosPhi * cosX + sinPhi * tgY), 0.0;
+                }
+            } else {
+                if (utils::isEqual(cosY, 0.0)) {
+                    row << 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0;
+                } else {
+                    row << 1.0, 0.0, rcosY, tgY, -cosX * tgY, sinX * tgY, cosPhi * sinX * rcosY,
+                        -(cosPhi * cosX + sinPhi * tgY);
+                }
+            }
+
+            X.row(i) = row;
+
+            if constexpr (MOUNT_TYPE == MccMountType::FORK_TYPE) {
+                if (utils::isEqual(cosX, 0.0)) {
+                    row << 0.0, 1.0, 0.0, 0.0, sinX, cosX, cosPhi * cosX * sinY - sinPhi * cosY, 0.0, 0.0;
+                } else {
+                    row << 0.0, 1.0, 0.0, 0.0, sinX, cosX, cosPhi * cosX * sinY - sinPhi * cosY, 0.0, 1.0 / cosX;
+                }
+            } else {
+                row << 0.0, 1.0, 0.0, 0.0, sinX, cosX, cosPhi * cosX * sinY - sinPhi * cosY, 0.0;
+            }
+
+            X.row(i + numberOfPoints()) = row;
+
+            y(i) = _colonRES[i];
+            y(i + numberOfPoints()) = _colatRES[i];
+        }
+
+        Eigen::VectorXd resi = y;
+        Eigen::VectorXd weights(2 * numberOfPoints());
+
+        double scale;
+
+        Eigen::MatrixXd WX;
+        Eigen::VectorXd Wy;
+
+        // initial parameters estimation (least squares)
+        beta = X.bdcSvd(Eigen::ComputeThinU | Eigen::ComputeThinV).solve(y);
+        model = X * beta;
+        resi = y - model;
+
+        // resi = y;
+
+        for (result.final_iter = 1; result.final_iter <= comp_params.max_iter; ++result.final_iter) {
+            scale = gastwirth_est(resi);
+
+            tukey_weight(resi / scale, comp_params.c, weights);
+
+            // Eigen::MatrixXd XtW = X.transpose() * weights.asDiagonal();
+            // Eigen::MatrixXd XtWX = XtW * X;
+            // Eigen::VectorXd XtWy = XtW * y;
+
+            // new_beta = XtWX.ldlt().solve(XtWy);
+
+            WX = weights.asDiagonal() * X;
+            Wy = weights.asDiagonal() * y;
+            new_beta = WX.bdcSvd(Eigen::ComputeThinU | Eigen::ComputeThinV).solve(Wy);
+
+            if ((new_beta - beta).norm() < comp_params.tolerance) {
+                break;
+            }
+
+            beta = new_beta;
+
+            model = X * beta;
+            resi = y - model;
+        }
+
+        pcm_data.geomCoefficients.zeroPointX = new_beta(0);
+        pcm_data.geomCoefficients.zeroPointY = new_beta(1);
+        pcm_data.geomCoefficients.collimationErr = new_beta(2);
+        pcm_data.geomCoefficients.nonperpendErr = new_beta(3);
+        pcm_data.geomCoefficients.misalignErr1 = new_beta(4);
+        pcm_data.geomCoefficients.misalignErr2 = new_beta(5);
+        pcm_data.geomCoefficients.tubeFlexure = new_beta(6);
+        pcm_data.geomCoefficients.DECaxisFlexure = new_beta(7);
+        if constexpr (MOUNT_TYPE == MccMountType::FORK_TYPE) {
+            pcm_data.geomCoefficients.forkFlexure = new_beta(8);
+        }
+
+        result.model_colon = {model.begin(), model.begin() + numberOfPoints()};
+        result.model_colat = {model.begin() + numberOfPoints(), model.end()};
+        result.colon_res.resize(numberOfPoints());
+        result.colat_res.resize(numberOfPoints());
+
+        result.colon_weight = {weights.begin(), weights.begin() + numberOfPoints()};
+        result.colat_weight = {weights.begin() + numberOfPoints(), weights.end()};
+
+        computeModelResi(result);
+
+        return result;
+    }
+};
+
+}  // namespace mcc::impl
\ No newline at end of file