From e1421a1c2ea43fb304e8249b3159b06c112d56c1 Mon Sep 17 00:00:00 2001
From: "Timur A. Fatkhullin" <timur@sao.ru>
Date: Tue, 29 Apr 2025 18:31:41 +0300
Subject: [PATCH] ...

---
 cxx/mount_astrom.h | 10 +++++-----
 cxx/mount_pz.h     |  8 ++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/cxx/mount_astrom.h b/cxx/mount_astrom.h
index 8a63c77..25cfb97 100644
--- a/cxx/mount_astrom.h
+++ b/cxx/mount_astrom.h
@@ -417,15 +417,15 @@ std::pair<std::chrono::duration<double>, std::chrono::duration<double>> mcc_time
 
     auto C1C3 = C1_2 + C3_2;
     auto D = C2_2 * C3_2 - C1C3 * (C2_2 - C1_2);
-    if (D < 0.0) {
+    if (D < 0.0) {  // object never reach given azimuth
         return {inf_dur, inf_dur};
     }
 
-    auto cos_t1 = -(C2C3 + sqrt(D)) / C1C3;
-    auto cos_t2 = -(C2C3 - sqrt(D)) / C1C3;
+    auto cos_ha1 = -(C2C3 + sqrt(D)) / C1C3;
+    auto cos_ha2 = -(C2C3 - sqrt(D)) / C1C3;
 
-    auto sin_z1 = (C2 + C3 * cos_t1) / cos_az;
-    auto sin_z2 = (C2 + C3 * cos_t2) / cos_az;
+    auto sin_z1 = (C2 + C3 * cos_ha1) / cos_az;
+    auto sin_z2 = (C2 + C3 * cos_ha2) / cos_az;
 
     auto ut1 = now + dut1;
     auto tt = now + tai_utc + tt_tai;
diff --git a/cxx/mount_pz.h b/cxx/mount_pz.h
index 0513067..9dd7bdb 100644
--- a/cxx/mount_pz.h
+++ b/cxx/mount_pz.h
@@ -235,6 +235,14 @@ public:
     bool inZone(const MccAngle& x, const MccAngle& y, const MccProhibitedZone::pzcontext_t& context)
     {
         if (context.coords_kind == MccProhibitedZone::COORDS_KIND_AZALT) {  // trivial case
+            auto xx = x;
+            xx.normalize<MccAngle::NORM_KIND_180_180>();  // to [-180, 180]
+
+            if (std::fabs(xx) <= _deltaAZ) {  // check at the South
+                return true;
+            } else if (std::fabs(xx - std::numbers::pi) <= _deltaAZ) {  // check at the North
+                return true;
+            }
         }
 
         return false;