diff --git a/src/Projection.cxx b/src/Projection.cxx
index f83b771..47d7e90 100644
--- a/src/Projection.cxx
+++ b/src/Projection.cxx
@@ -1387,9 +1387,11 @@ void to_map_single_thread(Pointer<C> &pointer,
     int n_det = pointer.DetCount();
     for (int i_det = 0; i_det < n_det; ++i_det) {
         FSIGNAL det_wt = 1.;
-        if (_det_weights->obj != NULL)
+        if (_det_weights->obj != NULL){
             det_wt = *(FSIGNAL*)((char*)_det_weights->buf +
                                  _det_weights->strides[0]*i_det);
+            if (det_wt == 0.) continue;
+        }
         double dofs[4];
         double coords[4];
         FSIGNAL pf[S::comp_count];
@@ -1423,9 +1425,11 @@ void to_weight_map_single_thread(Pointer<C> &pointer,
     int n_det = pointer.DetCount();
     for (int i_det = 0; i_det < n_det; ++i_det) {
         FSIGNAL det_wt = 1.;
-        if (_det_weights->obj != NULL)
+        if (_det_weights->obj != NULL){
             det_wt = *(FSIGNAL*)((char*)_det_weights->buf +
                                  _det_weights->strides[0]*i_det);
+            if (det_wt == 0.) continue;
+        }
         double dofs[4];
         double coords[4];
         FSIGNAL pf[S::comp_count];
@@ -1694,9 +1698,10 @@ void precomp_to_map_single_thread(Pixelizor2_Flat<TilingSys> &tiling,
 
     for (int i_det = 0; i_det < n_det; ++i_det) {
         FSIGNAL det_wt = 1.;
-        if (_det_weights->obj != NULL)
+        if (_det_weights->obj != NULL){
             det_wt = *(FSIGNAL*)((char*)_det_weights->buf + _det_weights->strides[0]*i_det);
-
+            if (det_wt == 0.) continue;
+        }
         for (auto const &rng: ivals[i_det].segments) {
             for (int i_time = rng.first; i_time < rng.second; ++i_time) {
                 const int *pixel_offset = pixel_buf_man.data_ptr[i_det] +
@@ -1728,9 +1733,10 @@ void precomp_to_weight_map_single_thread(Pixelizor2_Flat<TilingSys> &tiling,
     assert(spin_proj_man.steps[1] == 1); // assumed below
     for (int i_det = 0; i_det < n_det; ++i_det) {
         FSIGNAL det_wt = 1.;
-        if (_det_weights->obj != NULL)
+        if (_det_weights->obj != NULL){
             det_wt = *(FSIGNAL*)((char*)_det_weights->buf + _det_weights->strides[0]*i_det);
-
+            if (det_wt == 0.) continue;
+        }
         for (auto const &rng: ivals[i_det].segments) {
             for (int i_time = rng.first; i_time < rng.second; ++i_time) {
                 const int *pixel_offset = pixel_buf_man.data_ptr[i_det] +