diff --git a/cxx/mount_astrom.h b/cxx/mount_astrom.h
index 8e9eac5..f3098e3 100644
--- a/cxx/mount_astrom.h
+++ b/cxx/mount_astrom.h
@@ -55,6 +55,7 @@ template <traits::mcc_real_scalar_or_real_range_c ResT, traits::mcc_time_duratio
 static int mcc_julday(traits::mcc_systime_c auto const& start_time,
                       ResT& mjd,
                       const DT& step = std::chrono::milliseconds(100))
+    requires(!std::is_pointer_v<std::decay_t<ResT>>)
 {
     size_t mjd_size = 0;
     if constexpr (std::ranges::range<ResT>) {
@@ -101,7 +102,7 @@ static int mcc_julday(traits::mcc_systime_c auto const& start_time,
         constexpr size_t reg_size = xsimd::batch<double>::size;
         size_t vec_size = mjd_size - mjd_size % reg_size;
 
-        xsimd::batch<double> res_reg{mjd_float};
+        xsimd::batch<double> res_reg(mjd_float);
         xsimd::batch<double> step_reg = [d_step]<size_t... Is>(std::index_sequence<Is...>) {
             return xsimd::batch<double>{(Is * d_step)...};
         }(std::make_index_sequence<reg_size>{});
@@ -111,7 +112,7 @@ static int mcc_julday(traits::mcc_systime_c auto const& start_time,
         auto ptr = mjd.begin();
 
         // vectorized part
-        for (; i < vec_size; i += vec_size) {
+        for (; i < vec_size; i += reg_size) {
             res_reg += step_reg;
 
             if constexpr (std::ranges::contiguous_range<ResT>) {
@@ -143,6 +144,18 @@ static int mcc_julday(traits::mcc_systime_c auto const& start_time,
     return 0;
 }
 
+template <typename ResT, traits::mcc_time_duration_c DT = std::chrono::milliseconds>
+static int mcc_julday(traits::mcc_systime_c auto const& start_time,
+                      ResT& mjd,
+                      const DT& step = std::chrono::milliseconds(100))
+    requires std::is_pointer_v<std::decay_t<ResT>>
+{
+    auto sp = std::span(mjd);
+    int ret = mcc_julday(start_time, sp, step);
+    return ret;
+}
+
+
 /*
  *  angles are in degrees or sexagimal string form
  *  RA and DEC are apparent!
diff --git a/cxx/tests/astrom_test.cpp b/cxx/tests/astrom_test.cpp
index 53b0c37..ea87971 100644
--- a/cxx/tests/astrom_test.cpp
+++ b/cxx/tests/astrom_test.cpp
@@ -68,12 +68,39 @@ int main(int argc, char* argv[])
     // const double rr = 180.0 / std::numbers::pi * 60.0;
     // std::cout << "A(arcmin) = " << A * rr << "; B(arcmin) = " << B * rr << "\n";
 
+    float alt_lim = 10.0;
+    std::string_view ra_str = "06:30:00.0", dec_str = "00:00:00.0";
+    std::cout << "\n\nTimes to object (RA = " << ra_str << ", DEC = " << dec_str << ") sets to given altitude ("
+              << alt_lim << " degrees):\n";
     using namespace std::chrono_literals;
-    double stm = mcc::astrom::mcc_time_to_alt_limit(10.0, "06:30:00.0", "00:00:00.0", 43.646711, 41.440732,
+    double stm = mcc::astrom::mcc_time_to_alt_limit(alt_lim, ra_str, dec_str, 43.646711, 41.440732,
                                                     std::chrono::system_clock::now(), 0.041s, 32.184s, 37.0s);
 
     // auto stm_d = mcc::astrom::mcc_chrono_radians{stm};
     std::cout << "STM: " << stm * 12.0 / std::numbers::pi * 60.0 << " minutes\n";
 
+
+    std::cout << "\n\n\n";
+    const size_t N = 1000;
+    double mjds[N];
+    now = std::chrono::system_clock::now();
+    st = mcc::astrom::mcc_julday(now, mjds, std::chrono::milliseconds(100));
+    std::cout << std::format("comp time for {} MJDs = {}\n", N, std::chrono::system_clock::now() - now);
+    std::cout << std::format("MIN MJD: {:.16f}; \nMAX MJD: {:.16f}\n", mjds[0], mjds[N - 1]);
+
+    double elong = 43.646711 * std::numbers::pi / 180.0;
+    double phi = 41.440732 * std::numbers::pi / 180.0;
+    double aob, zob, hob, dob, rob, eo;
+
+    now = std::chrono::system_clock::now();
+
+    for (auto& el : mjds) {
+        st = erfa::eraAtco13(1.343523, 0.32352345, 0.0, 0.0, 0.0, 0.0, ERFA_DJM0, el, 0.041, elong, phi, 2100.0, 0.0,
+                             0.0, 700.0, 10.0, 0.8, 0.5, &aob, &zob, &hob, &dob, &rob, &eo);
+    }
+    std::cout << std::format(
+        "comp time for {} coordinate transf = {}\n", N,
+        std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now() - now));
+
     return ecode;
 }