diff --git a/cxx/CMakeLists.txt b/cxx/CMakeLists.txt
index 6771a1c..d83ec2d 100644
--- a/cxx/CMakeLists.txt
+++ b/cxx/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.14)
 
 # set(CMAKE_BUILD_TYPE Release)
 
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake")
@@ -122,7 +122,8 @@ add_library(${CNTR_PROTO_LIB} STATIC ${CNTR_PROTO_LIB_SRC})
 set(MOUNT_SERVER_APP_SRC mount.h mount_state.h mount_server.cpp comm_server.h comm_server_endpoint.h comm_server_configfile.h mount_astrom.h
     mount_astrom_default.h)
 set(MOUNT_SERVER_APP mount_server)
-add_executable(${MOUNT_SERVER_APP} ${MOUNT_SERVER_APP_SRC})
+add_executable(${MOUNT_SERVER_APP} ${MOUNT_SERVER_APP_SRC}
+    mcc_coord.h)
 # target_include_directories(${MOUNT_SERVER_APP} PUBLIC ${ERFA_INCLUDE_DIR})
 target_link_libraries(${MOUNT_SERVER_APP} ${CNTR_PROTO_LIB} spdlog::spdlog_header_only ERFA_LIB)
 
diff --git a/cxx/mcc_coord.h b/cxx/mcc_coord.h
new file mode 100644
index 0000000..6e4a895
--- /dev/null
+++ b/cxx/mcc_coord.h
@@ -0,0 +1,189 @@
+#pragma once
+
+#include "mcc_traits.h"
+#include "utils.h"
+
+namespace mcc
+{
+
+/*  MCC-LIBRARY COORDINATES REPRESENTATION DEFINITIONS AND CLASS   */
+
+constexpr double operator""_rads(long double val)  // angle in radians (no conversion)
+{
+    return val;
+}
+
+constexpr double operator""_degs(long double val)  // angle in degrees
+{
+    return val * std::numbers::pi / 180.0;
+}
+
+constexpr double operator""_dms(const char* s, size_t size)  // as a string "DEGREES:MINUTES:SECONDS"
+{
+    auto res = utils::parsAngleString(std::span{s, size});
+    if (res.has_value()) {
+        return res.value() * std::numbers::pi / 180.0;
+    } else {
+        throw std::invalid_argument("invalid sexagesimal representation");
+    }
+}
+
+constexpr double operator""_hms(const char* s, size_t size)  // as a string "HOURS:MINUTES:SECONDS"
+{
+    auto res = utils::parsAngleString(std::span{s, size}, true);
+    if (res.has_value()) {
+        return res.value() * std::numbers::pi / 180.0;
+    } else {
+        throw std::invalid_argument("invalid sexagesimal representation");
+    }
+}
+
+
+// tags for MccCoordinate class construction
+
+struct MccRadianTag {
+};
+struct MccDegreeTag {
+};
+static constexpr MccDegreeTag mcc_degrees{};
+struct MccHMSTag {
+};
+static constexpr MccHMSTag mcc_hms{};
+
+
+// coordinate representation class
+
+class MccCoordinate
+{
+    double _angleInRads{0.0};
+    int _precision{2};
+
+public:
+    MccCoordinate() = default;
+
+    // by default angle is in radians
+    MccCoordinate(std::convertible_to<double> auto const& val, const MccRadianTag tag = MccRadianTag{})
+        : _angleInRads(val)
+    {
+    }
+
+    // construct angle in degrees, e.g.:
+    //     auto ang = MccCoordinate{180.0, mcc_degrees};
+    MccCoordinate(std::convertible_to<double> auto const& val, const MccDegreeTag tag)
+    {
+        _angleInRads = val * std::numbers::pi / 180.0;
+    }
+
+    // constuct angle from sexagesimal representation, e.g.:
+    //     auto ang = MccCoordinate{"-12:34:56.789"}; // from degrees:minutes:seconds
+    MccCoordinate(traits::mcc_input_char_range auto const& val)
+    {
+        auto res = utils::parsAngleString(val);
+        if (res.has_value()) {
+            _angleInRads = res.value() * std::numbers::pi / 180.0;
+        } else {
+            throw std::invalid_argument("invalid sexagesimal representation");
+        }
+    }
+
+    // construct angle from sexagesimal representation, e.g.:
+    //     auto ang = MccCoordinate{"01:23:45.6789", mcc_hms}; // from hours:minutes:seconds
+    MccCoordinate(traits::mcc_input_char_range auto const& val, const MccHMSTag)
+    {
+        auto res = utils::parsAngleString(val, true);
+        if (res.has_value()) {
+            _angleInRads = res.value() * std::numbers::pi / 180.0;
+        } else {
+            throw std::invalid_argument("invalid sexagesimal representation");
+        }
+    }
+
+    operator double() const
+    {
+        return _angleInRads;
+    }
+
+    template <typename T>
+    T degrees() const
+    {
+        return _angleInRads * 180.0 / std::numbers::pi;
+    }
+
+    double degrees() const
+    {
+        return degrees<double>();
+    }
+
+    template <traits::mcc_output_char_range T>
+    T sexagesimal(bool hms, int prec = 2) const
+    {
+        return utils::rad2sxg(_angleInRads, hms, prec >= 0 ? prec : _precision);
+    }
+
+    std::string sexagesimal(bool hms, int prec = 2) const
+    {
+        return sexagesimal<std::string>(hms, prec);
+    }
+
+    friend MccCoordinate operator+(const MccCoordinate& left, const MccCoordinate& right)
+    {
+        return left._angleInRads + right._angleInRads;
+    }
+
+    friend MccCoordinate operator-(const MccCoordinate& left, const MccCoordinate& right)
+    {
+        return left._angleInRads + right._angleInRads;
+    }
+
+    template <typename T>
+    MccCoordinate operator*(T&& scalar)
+        requires std::is_arithmetic_v<std::remove_cvref_t<T>>
+    {
+        return _angleInRads * scalar;
+    }
+
+    template <typename T>
+    MccCoordinate operator/(T&& scalar)
+        requires std::is_arithmetic_v<std::remove_cvref_t<T>>
+    {
+        return _angleInRads / scalar;
+    }
+
+    template <typename T>
+    MccCoordinate operator-()  // unary '-'
+        requires std::is_arithmetic_v<std::remove_cvref_t<T>>
+    {
+        return -_angleInRads;
+    }
+
+    MccCoordinate& operator+=(const MccCoordinate& v)
+    {
+        _angleInRads += v._angleInRads;
+        return *this;
+    }
+
+    MccCoordinate& operator-=(const MccCoordinate& v)
+    {
+        _angleInRads += v._angleInRads;
+        return *this;
+    }
+
+    template <typename T>
+    MccCoordinate& operator*=(T&& scalar)
+        requires std::is_arithmetic_v<std::remove_cvref_t<T>>
+    {
+        _angleInRads *= scalar;
+        return *this;
+    }
+
+    template <typename T>
+    MccCoordinate& operator/=(T&& scalar)
+        requires std::is_arithmetic_v<std::remove_cvref_t<T>>
+    {
+        _angleInRads /= scalar;
+        return *this;
+    }
+};
+
+
+}  // namespace mcc
diff --git a/cxx/mount.h b/cxx/mount.h
index 44ca65a..1459422 100644
--- a/cxx/mount.h
+++ b/cxx/mount.h
@@ -10,6 +10,7 @@
 #include <string_view>
 #include "spdlog/sinks/null_sink.h"
 
+#include "mcc_coord.h"
 #include "mcc_spdlog.h"
 #include "mcc_traits.h"
 #include "mount_astrom.h"
@@ -45,6 +46,7 @@ concept mcc_mount_state_c = requires(T t, const T t_const) {
 }  // namespace traits
 
 
+
 /*   SOME BASIC DATA STRUCTURES DEFINITIONS  */
 
 // meteo parameters (e.g. to compute refraction)
@@ -195,32 +197,48 @@ public:
         _geoLocation.store(geoloc);
     }
 
-    void setSiteLatitude(auto const& lat)
+    void setSiteLatitude(const MccCoordinate& lat)
     {
-        auto v = utils::parsAngleString(lat);
-        if (v.has_value()) {
-            auto st = _geoLocation.load();
-            st.latitude = v.value() * utils::deg2radCoeff;  // to radians
-            logInfo("Set current site latitude to {} radians", st.latitude);
-            _geoLocation.store(st);
-        } else {
-            logError("Invalid user latitude value! Do not change the current value!");
-        }
+        auto st = _geoLocation.load();
+        st.latitude = lat;
+        logInfo("Set current site latitude to {} radians", st.latitude);
+        _geoLocation.store(st);
     }
 
-    void setSiteLongitude(auto const& lon)
+    void setSiteLongitude(const MccCoordinate& lon)
     {
-        auto v = utils::parsAngleString(lon);
-        if (v.has_value()) {
-            auto st = _geoLocation.load();
-            st.longitude = v.value() * utils::deg2radCoeff;  // to radians
-            logInfo("Set current site longitude to {} radians", st.longitude);
-            _geoLocation.store(st);
-        } else {
-            logError("Invalid user longitude value! Do not change the current value!");
-        }
+        auto st = _geoLocation.load();
+        st.longitude = lon;
+        logInfo("Set current site longitude to {} radians", st.longitude);
+        _geoLocation.store(st);
     }
 
+    // void setSiteLatitude(auto const& lat)
+    // {
+    //     auto v = utils::parsAngleString(lat);
+    //     if (v.has_value()) {
+    //         auto st = _geoLocation.load();
+    //         st.latitude = v.value() * utils::deg2radCoeff;  // to radians
+    //         logInfo("Set current site latitude to {} radians", st.latitude);
+    //         _geoLocation.store(st);
+    //     } else {
+    //         logError("Invalid user latitude value! Do not change the current value!");
+    //     }
+    // }
+
+    // void setSiteLongitude(auto const& lon)
+    // {
+    //     auto v = utils::parsAngleString(lon);
+    //     if (v.has_value()) {
+    //         auto st = _geoLocation.load();
+    //         st.longitude = v.value() * utils::deg2radCoeff;  // to radians
+    //         logInfo("Set current site longitude to {} radians", st.longitude);
+    //         _geoLocation.store(st);
+    //     } else {
+    //         logError("Invalid user longitude value! Do not change the current value!");
+    //     }
+    // }
+
     void setSiteElevation(MccMountSiteInfo::mnt_site_elev_t elev)
     {
         auto st = _geoLocation.load();
@@ -249,22 +267,34 @@ public:
     }
 
 
-    // prohibited zone related methods
+    /* prohibited zone related methods */
 
-    bool pzCheck(traits::mcc_real_or_char_range auto const& xcoord, traits::mcc_real_or_char_range auto const& ycoord)
+    // returns a time to reach the prohibited area:
+    //     0 - already in the zone
+    //     std::chrono::sys_time<>::max() - never reach the zone
+    // the kind of cordinates (e.g. IRCS or apparent, equatorial or horizontal) is a subject of implementation
+    auto pzTimeTo(const MccCoordinate& xcoord,
+                  const MccCoordinate& ycoord,
+                  traits::mcc_systime_c auto const& utc = std::chrono::system_clock::now())
     {
-        return true;
-    }
-
-    auto pzPredict(traits::mcc_systime_c auto const& time_point,
-                   traits::mcc_real_or_char_range auto const& xcoord,
-                   traits::mcc_real_or_char_range auto const& ycoord)
-    {
-        using d_t = std::remove_cvref_t<decltype(time_point)>::duration;
+        using d_t = std::remove_cvref_t<decltype(utc)>::duration;
 
         return d_t::max();
     }
 
+    // returns a time to exit the prohibited area:
+    //     0 - already out of the zone
+    //     std::chrono::sys_time<>::max() - the zone itself
+    // the kind of cordinates (e.g. IRCS or apparent, equatorial or horizontal) is a subject of implementation
+    auto pzTimeFrom(const MccCoordinate& xcoord,
+                    const MccCoordinate& ycoord,
+                    traits::mcc_systime_c auto const& utc = std::chrono::system_clock::now())
+    {
+        using d_t = std::remove_cvref_t<decltype(utc)>::duration;
+
+        return d_t{0};
+    }
+
 
     // IERS databases updater
 
diff --git a/cxx/mount_state.h b/cxx/mount_state.h
index 2effc3b..3c356b8 100644
--- a/cxx/mount_state.h
+++ b/cxx/mount_state.h
@@ -16,7 +16,7 @@ namespace mcc
 
 class MccMountAbstractState
 {
-    std::function<void()> _getMountStateFunc{[]() {}};
+    std::function<void()> _getMountDataFunc{[]() {}};
 
 public:
     typedef std::error_code mount_state_error_t;
@@ -34,7 +34,7 @@ public:
                           std::convertible_to<exit_callback_t> auto&& exit_callback,
                           std::convertible_to<error_callback_t> auto&& error_callback)
     {
-        _getMountStateFunc = [&mount_ptr, this]() { auto mstate = mount_ptr->getMountData(); };
+        _getMountDataFunc = [&mount_ptr, this]() { auto mstate = mount_ptr->getMountData(); };
     }
 
 
@@ -43,7 +43,7 @@ public:
 
     std::string_view ident() const
     {
-        return "MCC-ABSTRACT-MOUNT-STATE";
+        return "MCC-MOUNT-ABSTRACT-STATE";
     }
 
 
@@ -51,6 +51,12 @@ public:
 
     void exit() {}
 
+    // #ifdef __cpp_explicit_this_parameter
+    // #if __cpp_explicit_this_parameter >= 202110L
+    //     void aaa() {}
+    // #endif
+    // #endif
+
 protected:
     enter_callback_t _enterCallback{[](const mount_state_error_t&) {}};
     exit_callback_t _exitCallback{[](const mount_state_error_t&) {}};
diff --git a/cxx/utils.h b/cxx/utils.h
index 9076f4e..7ca2839 100644
--- a/cxx/utils.h
+++ b/cxx/utils.h
@@ -2,6 +2,7 @@
 
 #include <charconv>
 #include <cmath>
+#include <cstring>
 #include <format>
 #include <numbers>
 #include <ranges>
@@ -147,6 +148,11 @@ static std::optional<double> parsAngleString(R&& r, bool hms = false)
     return std::nullopt;
 }
 
+static std::optional<double> parsAngleString(const char* s, bool hms = false)
+{
+    return parsAngleString(std::span{s, std::strlen(s)}, hms);
+}
+
 
 static constexpr auto deg2radCoeff = std::numbers::pi / 180.0;