diff --git a/cxx/mcc_mount_astrom.h b/cxx/mcc_mount_astrom.h
index 610aa18..dba829e 100644
--- a/cxx/mcc_mount_astrom.h
+++ b/cxx/mcc_mount_astrom.h
@@ -40,7 +40,7 @@ concept mcc_astrom_engine_c = requires(T t, const T t_const) {
 
     /*    coordinates conversional methods    */
 
-    // ICRS RA and DEC to observed place: icrs2obs(ra, dec, jd, ra_app, dec_app, ha, az, alt, eo)
+    // ICRS RA and DEC to observed place: icrs2obs(ra, dec, pra, pdec, plx, jd, ra_app, dec_app, ha, az, alt, eo)
     {
         t.icrs2obs(std::declval<typename T::coord_t>(), std::declval<typename T::coord_t>(),
                    std::declval<typename T::prop_motion_t>(), std::declval<typename T::prop_motion_t>(),
diff --git a/cxx/mcc_mount_config.h b/cxx/mcc_mount_config.h
index 358fb14..1d67ebb 100644
--- a/cxx/mcc_mount_config.h
+++ b/cxx/mcc_mount_config.h
@@ -2,12 +2,26 @@
 
 /*  MOUNT CONTROL COMPONENTS LIBRARY  */
 
+#include "mcc_mount_astrom.h"
 #include "mcc_mount_coord.h"
-#include "mount_astrom.h"
+#include "mcc_mount_hardware.h"
 
 namespace mcc
 {
 
+
+namespace traits
+{
+
+template <typename T>
+concept mcc_mount_config_c = requires(T t) {
+    { t.astromEngine() } -> traits::mcc_astrom_engine_c;
+    { t.hardware() } -> traits::mcc_mount_hardware_c;
+};
+
+}  // namespace traits
+
+
 // meteo parameters (e.g. to compute refraction)
 struct MccMountMeteo {
     typedef double temp_t;
@@ -45,15 +59,14 @@ static constexpr std::string_view MccMountTypeStr = TYPE == MccMountType::GERMAN
                                                                                            : "UNKNOWN";
 
 // mount configuration
-template <MccMountType MOUNT_TYPE>
+template <MccMountType MOUNT_TYPE,
+          traits::mcc_astrom_engine_c ASTROM_ENGINE_TYPE,
+          traits::mcc_mount_hardware_c HARDWARE_TYPE>
 struct MccMountConfig {
     static constexpr MccMountType mountType = MOUNT_TYPE;
 
     virtual ~MccMountConfig() = default;
 
-    astrom::MccLeapSeconds leapSeconds;
-    astrom::MccIersBulletinA iersBulletinA;
-
     MccMountSiteInfo siteInfo{.latitude = 0.0, .longitude = 0.0, .elevation = 0.0, .name{"ALL-ZERO"}};
 
     MccMountMeteo ambientMeteo{.temperature = 0.0, .humidity = 0.5, .pressure = 1010.0};
diff --git a/cxx/mcc_mount_hardware.h b/cxx/mcc_mount_hardware.h
index 91f398f..486ecb7 100644
--- a/cxx/mcc_mount_hardware.h
+++ b/cxx/mcc_mount_hardware.h
@@ -80,11 +80,11 @@ concept mcc_tuple_motor_ref_c = mcc_tuple_c<T> && requires(T t) {
 
 
 template <typename T>
-concept mcc_hw_enc_lref_c = std::is_lvalue_reference_v<T> && mcc_hw_encoder_c<std::remove_cvref_t<T>>;
+concept mcc_hw_enc_lref_c = std::is_lvalue_reference_v<T> && mcc_hw_encoder_c<std::remove_reference_t<T>>;
 
 
 template <typename T>
-concept mcc_hw_motor_lref_c = std::is_lvalue_reference_v<T> && mcc_hw_motor_c<std::remove_cvref_t<T>>;
+concept mcc_hw_motor_lref_c = std::is_lvalue_reference_v<T> && mcc_hw_motor_c<std::remove_reference_t<T>>;
 
 }  // namespace details
 
diff --git a/cxx/mcc_traits.h b/cxx/mcc_traits.h
index a3804d4..21ec782 100644
--- a/cxx/mcc_traits.h
+++ b/cxx/mcc_traits.h
@@ -158,6 +158,10 @@ concept mcc_tuple_c = requires {
     };
 };
 
+
+template <typename T>
+concept mcc_nonconst_ref = std::is_lvalue_reference_v<T> && !std::is_const_v<std::remove_reference_t<T>>;
+
 namespace details
 {