diff --git a/maps/CMakeLists.txt b/maps/CMakeLists.txt
index 7f47cb37..9768653d 100644
--- a/maps/CMakeLists.txt
+++ b/maps/CMakeLists.txt
@@ -6,6 +6,7 @@ add_spt3g_library(maps SHARED
   src/HealpixSkyMap.cxx
   src/FlatSkyProjection.cxx
   src/FlatSkyMap.cxx
+  src/HitsBinner.cxx
   src/MapBinner.cxx
   src/MapMockObserver.cxx
   src/MapTODMasker.cxx
diff --git a/maps/src/HitsBinner.cxx b/maps/src/HitsBinner.cxx
new file mode 100644
index 00000000..b4cf90a7
--- /dev/null
+++ b/maps/src/HitsBinner.cxx
@@ -0,0 +1,267 @@
+#include <pybindings.h>
+#ifdef OPENMP_FOUND
+#include <omp.h>
+#endif
+
+#include <G3Module.h>
+#include <G3Timestream.h>
+#include <G3Quat.h>
+#include <G3Data.h>
+#include <G3Map.h>
+#include <maps/G3SkyMap.h>
+#include <maps/pointing.h>
+#include <calibration/BoloProperties.h>
+
+class HitsBinner : public G3Module {
+public:
+	HitsBinner(std::string output_map_id, const G3SkyMap &stub_map,
+	    std::string pointing, std::string timestreams,
+	    std::string bolo_properties_name, boost::python::object map_per_scan);
+	virtual ~HitsBinner() {}
+
+	void Process(G3FramePtr frame, std::deque<G3FramePtr> &out);
+
+private:
+	void BinHits(const BolometerProperties &bp, const G3VectorQuat &pointing,
+	    G3SkyMapPtr H);
+
+	std::string output_id_;
+	std::string pointing_;
+	std::string timestreams_;
+	std::string boloprops_name_;
+	int map_per_scan_;
+	boost::python::object map_per_scan_callback_;
+
+	G3SkyMapPtr H_;
+	G3Time start_, stop_;
+
+	BolometerPropertiesMapConstPtr boloprops_;
+
+	SET_LOGGER("HitsBinner");
+};
+
+EXPORT_G3MODULE("maps", HitsBinner,
+    (init<std::string, const G3SkyMap &, std::string, std::string, std::string,
+     object>((arg("map_id"), arg("stub_map"), arg("pointing"),
+     arg("timestreams"), arg("bolo_properties_name")="BolometerProperties",
+     arg("map_per_scan")=false))),
+"HitsBinner(map_id, stub_map, pointing, timestreams, bolo_properties_name=\"BolometerProperties\", map_per_scan=False)\n"
+"\n"
+"Bins up pointing for a set of channels into a hits map with properties (projection, etc.) \n"
+"specified by the stub_map argument. \n\n"
+"Parameters\n"
+"----------\n"
+"map_id : string\n"
+"    Will be set as the \"Id\" element of the output frame from this module.\n"
+"stub_map : G3SkyMap\n"
+"    Template of the map in which to accumulate timestream data. All \n"
+"    parameters of the output map (projection, boundaries, pixel size, etc.) \n"
+"    are copied from this map, which is not modified.\n"
+"pointing : string (frame object G3TimestreamQuat)\n"
+"    Name of a frame object containing the boresight pointing quaternion \n"
+"    timestream. Must be present in every Scan frame.\n"
+"timestreams : string (frame object G3TimestreamMap)\n"
+"    Name of a frame object containing the timestreams to be binned into the \n"
+"    output map. Must exist in every Scan frame that is to be binned. \n"
+"    This key is used only to determine the subset of channels to bin into \n"
+"    the hits map.\n"
+"bolo_properties_name : string, optional (frame object BolometerPropertiesMap)\n"
+"    Name of a bolometer properties map containing detector pointing offsets\n"
+"    from boresight. These are usually named \"BolometerProperties\", the \n"
+"    default, and this parameter only need be set if you wish to use \n"
+"    alternative values.\n"
+"map_per_scan: boolean or callable, optional\n"
+"    Defaults to False. If set to True, will make an output map for every \n"
+"    input Scan frame, which can be useful for fine-grained time-domain \n"
+"    maps. Can also be set to a Python callable for complex situations. In \n"
+"    this case, the callable will be called on each Scan frame and passed \n"
+"    the frame as an argument. If it returns True, the map binner will emit \n"
+"    a map frame with the data since the last emitted map frame but *before* \n"
+"    the current Scan; if False, the binner will continue accumulating data.\n"
+"\n"
+"Emits\n"
+"-----\n"
+"Emits a frame of type Map at the end of processing containing the output \n"
+"map:\n\n"
+"Frame (Map) [\n"
+"\"Id\" (spt3g.core.G3String) => \"ra0hdec-57.5-150GHz\"\n"
+"\"H\" (spt3g.maps.FlatSkyMap) => 2700 x 1500 (45 x 25 deg) ZEA centered at (1350, 749.5) = (0, -57.5 deg) in equatorial coordinates  (Tcmb)\n"
+"]\n"
+"\n"
+"See Also\n"
+"--------\n"
+"MapBinner, SingleDetectorMapBinner, SingleDetectorBoresightBinner :\n"
+"    Alternative map binners.\n"
+"FlatSkyMap, HealpixSkyMap :\n"
+"    Possible output types.\n"
+"\n"
+"Examples\n"
+"--------\n"
+".. code-block:: python\n"
+"\n"
+"    pipe.Add(\n"
+"        maps.HitsBinner,\n"
+"        map_id=\"150GHz\",\n"
+"        stub_map=map_params,\n"
+"        timestreams=\"DeflaggedTimestreams150GHz\",\n"
+"        pointing=\"OfflineRaDecRotation\",\n"
+"    )\n"
+);
+
+
+HitsBinner::HitsBinner(std::string output_map_id, const G3SkyMap &stub_map,
+    std::string pointing, std::string timestreams, std::string bolo_properties_name,
+    boost::python::object map_per_scan) :
+  output_id_(output_map_id), pointing_(pointing), timestreams_(timestreams),
+  boloprops_name_(bolo_properties_name)
+{
+	H_ = stub_map.Clone(false);
+	H_->pol_type = G3SkyMap::None;
+	H_->SetPolConv(G3SkyMap::ConvNone);
+	H_->units = G3Timestream::None;
+
+	if (PyCallable_Check(map_per_scan.ptr())) {
+		map_per_scan_callback_ = map_per_scan;
+		map_per_scan_ = -1;
+	} else {
+		map_per_scan_ = boost::python::extract<bool>(map_per_scan)();
+	}
+}
+
+void
+HitsBinner::Process(G3FramePtr frame, std::deque<G3FramePtr> &out)
+{
+	if (frame->Has(boloprops_name_))
+		boloprops_ = frame->Get<BolometerPropertiesMap>(
+		    boloprops_name_);
+
+	bool emit_map_now = false;
+	if (frame->type == G3Frame::EndProcessing)
+		emit_map_now = true;
+	else if (frame->type == G3Frame::Scan) {
+		if (start_.time != 0) { // Data exist
+			if (map_per_scan_ >= 0)
+				emit_map_now = map_per_scan_;
+			else
+				emit_map_now = map_per_scan_callback_(frame);
+		}
+	}
+	
+	if (emit_map_now) {
+		G3FramePtr out_frame(new G3Frame(G3Frame::Map));
+		out_frame->Put("Id", G3StringPtr(new G3String(output_id_)));
+		out_frame->Put("H", boost::dynamic_pointer_cast<G3FrameObject>(H_));
+		H_ = H_->Clone(false);
+
+		out_frame->Put("StartTime", G3TimePtr(new G3Time(start_)));
+		out_frame->Put("StopTime", G3TimePtr(new G3Time(stop_)));
+		start_.time = stop_.time = 0;
+
+		out.push_back(out_frame);
+	}
+
+	if (frame->type != G3Frame::Scan) {
+		out.push_back(frame);
+		return;
+	}
+
+	if (!boloprops_)
+		log_fatal("Need bolometer properties before detector data "
+		    "can be processed.");
+
+	// NB: First error (wrong type) is regarded as more severe
+	// than the pointing simply being absent, since it is a
+	// configuration error rather than a data error, so it is
+	// guaranteed nothing will ever work.
+	if (!frame->Has<G3TimestreamQuat>(pointing_) &&
+	    frame->Has<G3VectorQuat>(pointing_))
+		log_fatal("Pointing %s is a G3VectorQuat, but must "
+		    "contain timing information for simulation. "
+		    "Please turn it into a G3TimestreamQuat before "
+		    "running this module, for example by adding the "
+		    "shim module maps.AddTimingToPointingQuats.",
+		    pointing_.c_str());
+
+	G3TimestreamQuatConstPtr pointing =
+	    frame->Get<G3TimestreamQuat>(pointing_, false);
+	if (!pointing) {
+		log_error("Missing pointing %s", pointing_.c_str());
+		out.push_back(frame);
+		return;
+	}
+
+	G3TimestreamMapConstPtr timestreams =
+	    frame->Get<G3TimestreamMap>(timestreams_, false);
+	if (!timestreams) {
+		log_error("Missing timestreams %s", timestreams_.c_str());
+		out.push_back(frame);
+		return;
+	}
+
+	// Update start and stop times for map
+	if (start_.time == 0 || start_ > pointing->start)
+		start_ = pointing->start;
+	if (stop_ < pointing->stop)
+		stop_ = pointing->stop;
+
+#ifdef OPENMP_FOUND
+	if (omp_get_num_threads() > 1) {
+		// G3SkyMap is not thread-safe when sparse. Avoid the cost of locks
+		// by making one set of sparse maps per thread per scan (which use
+		// essentially zero memory) and then co-adding them at the end of
+		// the scan.
+
+		// Create a list of detectors to satisfy OpenMP's need for scalar
+		// iteration
+		std::vector<std::string> dets;
+		for (auto i : *timestreams)
+			dets.push_back(i.first);
+
+		// Clamp num_threads to prevent memory balloon?
+		#pragma omp parallel
+		{
+			G3SkyMapPtr scanH;
+
+			scanH = H_->Clone(false);
+
+			#pragma omp for
+			for (size_t i = 0; i < dets.size(); i++) {
+				BinHits(boloprops_->at(dets[i]), *pointing, scanH);
+			}
+
+			#pragma omp critical
+			{
+				// One thread at a time here
+				(*H_) += *scanH;
+			}
+		}
+
+	} else {
+#endif
+		for (auto ts : *timestreams) {
+			BinHits(boloprops_->at(ts.first), *pointing, H_);
+		}
+#ifdef OPENMP_FOUND
+	}
+#endif
+
+	out.push_back(frame);
+}
+
+void
+HitsBinner::BinHits(const BolometerProperties &bp, const G3VectorQuat &pointing,
+    G3SkyMapPtr H)
+    // Do shared pointers add too much overhead here? Probably not...
+{
+	// Get per-detector pointing timestream
+
+	std::vector<double> alpha, delta;
+	get_detector_pointing(bp.x_offset, bp.y_offset, pointing, H->coord_ref,
+	    alpha, delta);
+
+	auto detpointing = H->AnglesToPixels(alpha, delta);
+
+	for (size_t i = 0; i < detpointing.size(); i++) {
+		(*H)[detpointing[i]] += 1.0;
+	}
+}