diff --git a/src/kbmod/analysis_utils.py b/src/kbmod/analysis_utils.py
index 4f8e05881..66c0106e8 100644
--- a/src/kbmod/analysis_utils.py
+++ b/src/kbmod/analysis_utils.py
@@ -147,12 +147,6 @@ def load_images(
         print(f"Loaded {len(images)} images")
         stack = kb.ImageStack(images)
 
-        # Create a list of visit times and visit times shifted to 0.0.
-        min_time = min(visit_times)
-        zero_shifted = [(t - min_time) for t in visit_times]
-        stack.set_times(zero_shifted)
-        print("Times set", flush=True)
-
         return (stack, wcs_list, visit_times)
 
 
diff --git a/src/kbmod/search/image_stack.cpp b/src/kbmod/search/image_stack.cpp
index 893dd20ae..bcc9e07f0 100644
--- a/src/kbmod/search/image_stack.cpp
+++ b/src/kbmod/search/image_stack.cpp
@@ -7,10 +7,9 @@ namespace py = pybind11;
 namespace search {
   ImageStack::ImageStack(const std::vector<std::string>& filenames, const std::vector<PSF>& psfs) {
     verbose = true;
-    reset_images();
+    images = std::vector<LayeredImage>();
     load_images(filenames, psfs);
-    extract_image_times();
-    set_time_origin();
+
     global_mask = RawImage(get_width(), get_height());
     global_mask.set_all_pix(0.0);
   }
@@ -18,8 +17,7 @@ namespace search {
   ImageStack::ImageStack(const std::vector<LayeredImage>& imgs) {
     verbose = true;
     images = imgs;
-    extract_image_times();
-    set_time_origin();
+
     global_mask = RawImage(get_width(), get_height());
     global_mask.set_all_pix(0.0);
   }
@@ -42,39 +40,32 @@ namespace search {
     if (verbose) std::cout << "\n";
   }
 
-  void ImageStack::extract_image_times() {
-    // Load image times
-    image_times = std::vector<float>();
-    for (auto& i : images) {
-      image_times.push_back(float(i.get_obstime()));
-    }
-  }
-
-  void ImageStack::set_time_origin() {
-    // Set beginning time to 0.0
-    double initial_time = image_times[0];
-    for (auto& t : image_times) t = t - initial_time;
-  }
-
   LayeredImage& ImageStack::get_single_image(int index) {
     if (index < 0 || index > images.size()) throw std::out_of_range("ImageStack index out of bounds.");
     return images[index];
   }
 
-  void ImageStack::set_single_image(int index, LayeredImage& img) {
+  float ImageStack::get_obstime(int index) const {
     if (index < 0 || index > images.size()) throw std::out_of_range("ImageStack index out of bounds.");
-    images[index] = img;
+    return images[index].get_obstime();
   }
 
-  void ImageStack::set_times(const std::vector<float>& times) {
-    if (times.size() != img_count())
-      throw std::runtime_error("List of times provided does not match the number of images!");
-    image_times = times;
-    set_time_origin();
+  float ImageStack::get_zeroed_time(int index) const {
+    if (index < 0 || index > images.size()) throw std::out_of_range("ImageStack index out of bounds.");
+    return images[index].get_obstime() - images[0].get_obstime();
   }
 
-  void ImageStack::reset_images() { images = std::vector<LayeredImage>(); }
-
+  std::vector<float> ImageStack::build_zeroed_times() const {
+    std::vector<float> zeroed_times = std::vector<float>();
+    if (images.size() > 0) {
+      float t0 = images[0].get_obstime();
+      for (auto& i : images) {
+        zeroed_times.push_back(i.get_obstime() - t0);
+      }
+    }
+    return zeroed_times;
+  }
+    
   void ImageStack::convolve_psf() {
     for (auto& i : images) i.convolve_psf();
   }
@@ -141,9 +132,9 @@ namespace search {
       .def("get_single_image", &is::get_single_image,
            py::return_value_policy::reference_internal,
            pydocs::DOC_ImageStack_get_single_image)
-      .def("set_single_image", &is::set_single_image, pydocs::DOC_ImageStack_set_single_image)
-      .def("get_times", &is::get_times, pydocs::DOC_ImageStack_get_times)
-      .def("set_times", &is::set_times, pydocs::DOC_ImageStack_set_times )
+      .def("get_obstime", &is::get_obstime, pydocs::DOC_ImageStack_get_obstime)
+      .def("get_zeroed_time", &is::get_zeroed_time, pydocs::DOC_ImageStack_get_zeroed_time)
+      .def("build_zeroed_times", &is::build_zeroed_times, pydocs::DOC_ImageStack_build_zeroed_times)
       .def("img_count", &is::img_count, pydocs::DOC_ImageStack_img_count)
       .def("apply_mask_flags", &is::apply_mask_flags, pydocs::DOC_ImageStack_apply_mask_flags)
       .def("apply_mask_threshold", &is::apply_mask_threshold, pydocs::DOC_ImageStack_apply_mask_threshold)
diff --git a/src/kbmod/search/image_stack.h b/src/kbmod/search/image_stack.h
index 12d56affe..f9c5acac1 100644
--- a/src/kbmod/search/image_stack.h
+++ b/src/kbmod/search/image_stack.h
@@ -23,14 +23,12 @@ namespace search {
     unsigned get_height() const { return images.size() > 0 ? images[0].get_height() : 0; }
     unsigned get_npixels() const { return images.size() > 0 ? images[0].get_npixels() : 0; }
     std::vector<LayeredImage>& get_images() { return images; }
-    const std::vector<float>& get_times() const { return image_times; }
-    float* get_timesDataRef() { return image_times.data(); }
     LayeredImage& get_single_image(int index);
 
-    // Simple setters.
-    void set_times(const std::vector<float>& times);
-    void reset_images();
-    void set_single_image(int index, LayeredImage& img);
+    // Functions for getting times.
+    float get_obstime(int index) const;
+    float get_zeroed_time(int index) const;
+    std::vector<float> build_zeroed_times() const;  // Linear cost.
 
     // Apply makes to all the images.
     void apply_global_mask(int flags, int threshold);
@@ -49,12 +47,9 @@ namespace search {
 
   private:
     void load_images(const std::vector<std::string>& filenames, const std::vector<PSF>& psfs);
-    void extract_image_times();
-    void set_time_origin();
     void create_global_mask(int flags, int threshold);
     std::vector<LayeredImage> images;
     RawImage global_mask;
-    std::vector<float> image_times;
     bool verbose;
   };
 
diff --git a/src/kbmod/search/pydocs/image_stack_docs.h b/src/kbmod/search/pydocs/image_stack_docs.h
index ed21bf377..b6593feb0 100644
--- a/src/kbmod/search/pydocs/image_stack_docs.h
+++ b/src/kbmod/search/pydocs/image_stack_docs.h
@@ -5,30 +5,32 @@ namespace pydocs {
   static const auto DOC_ImageStack = R"doc(
   todo
   )doc";
-
+      
   static const auto DOC_ImageStack_get_images = R"doc(
   todo
   )doc";
 
-  static const auto DOC_ImageStack_get_single_image = R"doc(
-  todo
+  static const auto DOC_ImageStack_img_count = R"doc(
+  Returns the number of images in the stack.
   )doc";
 
-  static const auto DOC_ImageStack_set_single_image = R"doc(
-  todo
+  static const auto DOC_ImageStack_get_single_image = R"doc(
+  Returns a single LayeredImage for a given index.
   )doc";
 
-  static const auto DOC_ImageStack_get_times = R"doc(
-  todo
+  static const auto DOC_ImageStack_get_obstime = R"doc(
+  Returns a single image's observation time in MJD.
   )doc";
 
-  static const auto DOC_ImageStack_set_times = R"doc(
-  todo
+  static const auto DOC_ImageStack_get_zeroed_time = R"doc(
+  Returns a single image's observation time relative to that
+  of the first image.
   )doc";
 
-  static const auto DOC_ImageStack_img_count = R"doc(
-  todo
-  )doc";
+  static const auto DOC_ImageStack_build_zeroed_times = R"doc(
+  Construct an array of time differentials between each image
+  in the stack and the first image.
+  ")doc";
 
   static const auto DOC_ImageStack_apply_mask_flags = R"doc(
   todo
diff --git a/src/kbmod/search/stack_search.cpp b/src/kbmod/search/stack_search.cpp
index 6d3d6e4c1..2d1ebd3b0 100644
--- a/src/kbmod/search/stack_search.cpp
+++ b/src/kbmod/search/stack_search.cpp
@@ -110,9 +110,10 @@ namespace search {
     end_timer();
 
     // Create a data stucture for the per-image data.
+    std::vector<float> image_times = stack.build_zeroed_times();
     PerImageData img_data;
     img_data.num_images = stack.img_count();
-    img_data.image_times = stack.get_timesDataRef();
+    img_data.image_times = image_times.data();
     if (params.use_corr) img_data.bary_corrs = &bary_corrs[0];
 
     // Compute the encoding parameters for psi and phi if needed.
@@ -428,9 +429,10 @@ namespace search {
     const int height = stack.get_height();
 
     // Create a data stucture for the per-image data.
+    std::vector<float> image_times = stack.build_zeroed_times();
     PerImageData img_data;
     img_data.num_images = num_images;
-    img_data.image_times = stack.get_timesDataRef();
+    img_data.image_times = image_times.data();
 
     // Allocate space for the results.
     const int num_trajectories = t_array.size();
@@ -479,7 +481,7 @@ namespace search {
   }
 
   PixelPos StackSearch::get_trajectory_position(const Trajectory& t, int i) const {
-    float time = stack.get_times()[i];
+    float time = stack.get_zeroed_time(i);
     if (use_corr) {
       return {t.x + time * t.vx + bary_corrs[i].dx + t.x * bary_corrs[i].dxdx + t.y * bary_corrs[i].dxdy,
         t.y + time * t.vy + bary_corrs[i].dy + t.x * bary_corrs[i].dydx +
@@ -513,7 +515,7 @@ namespace search {
     int img_size = imgs.size();
     std::vector<float> lightcurve;
     lightcurve.reserve(img_size);
-    const std::vector<float>& times = stack.get_times();
+    std::vector<float> times = stack.build_zeroed_times();
     for (int i = 0; i < img_size; ++i) {
       /* Do not use get_pixel_interp(), because results from create_curves must
        * be able to recover the same likelihoods as the ones reported by the
diff --git a/tests/test_analysis_utils.py b/tests/test_analysis_utils.py
index 78679dbde..17215184f 100644
--- a/tests/test_analysis_utils.py
+++ b/tests/test_analysis_utils.py
@@ -201,8 +201,8 @@ def test_apply_stamp_filter(self):
             int(self.img_count / 2),
         )
 
-        mjds = np.array(stack.get_times())
-        kb_post_process = PostProcess(self.config, mjds)
+        zeroed_times = np.array(stack.build_zeroed_times())
+        kb_post_process = PostProcess(self.config, zeroed_times)
 
         keep = kb_post_process.load_and_filter_results(
             search,
@@ -302,7 +302,7 @@ def test_clustering(self):
         cluster_params["y_size"] = self.dim_y
         cluster_params["vel_lims"] = [self.min_vel, self.max_vel]
         cluster_params["ang_lims"] = [self.min_angle, self.max_angle]
-        cluster_params["mjd"] = np.array(self.stack.get_times())
+        cluster_params["mjd"] = np.array(self.stack.build_zeroed_times())
 
         trjs = [
             self._make_trajectory(10, 11, 1, 2, 100.0),
diff --git a/tests/test_image_stack.py b/tests/test_image_stack.py
index 52e4327ab..d921d8d32 100644
--- a/tests/test_image_stack.py
+++ b/tests/test_image_stack.py
@@ -19,7 +19,7 @@ def setUp(self):
                 60,  # dim_y = 60 pixels,
                 2.0,  # noise_level
                 4.0,  # variance
-                2.0 * i,  # time
+                2.0 * i + 1.0,  # time
                 self.p[i],
             )
 
@@ -38,7 +38,7 @@ def test_create(self):
     def test_access(self):
         # Test we can access an individual image.
         img = self.im_stack.get_single_image(1)
-        self.assertEqual(img.get_obstime(), 2.0)
+        self.assertEqual(img.get_obstime(), 3.0)
         self.assertEqual(img.get_name(), "layered_test_1")
 
         # Test an out of bounds access.
@@ -46,19 +46,16 @@ def test_access(self):
             img = self.im_stack.get_single_image(self.num_images + 1)
 
     def test_times(self):
-        times = self.im_stack.get_times()
+        # Check that we can access specific times.
+        self.assertEqual(self.im_stack.get_obstime(1), 3.0)
+        self.assertEqual(self.im_stack.get_zeroed_time(1), 2.0)
+
+        # Check that we can build the full zeroed times list.
+        times = self.im_stack.build_zeroed_times()
         self.assertEqual(len(times), self.num_images)
         for i in range(self.num_images):
             self.assertEqual(times[i], 2.0 * i)
 
-        new_times = [3.0 * i for i in range(self.num_images)]
-        self.im_stack.set_times(new_times)
-
-        times2 = self.im_stack.get_times()
-        self.assertEqual(len(times2), self.num_images)
-        for i in range(self.num_images):
-            self.assertEqual(times2[i], 3.0 * i)
-
     def test_apply_mask(self):
         # Nothing is initially masked.
         for i in range(self.num_images):
diff --git a/tests/test_search.py b/tests/test_search.py
index cf0c906b8..925db4a79 100644
--- a/tests/test_search.py
+++ b/tests/test_search.py
@@ -254,7 +254,7 @@ def test_sci_viz_stamps(self):
         sci_stamps = self.search.get_stamps(self.trj, 2)
         self.assertEqual(len(sci_stamps), self.imCount)
 
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         for i in range(self.imCount):
             self.assertEqual(sci_stamps[i].get_width(), 5)
             self.assertEqual(sci_stamps[i].get_height(), 5)
@@ -278,7 +278,7 @@ def test_stacked_sci(self):
         self.assertEqual(sci.get_height(), 5)
 
         # Compute the true stacked pixel for the middle of the track.
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         sum_middle = 0.0
         for i in range(self.imCount):
             t = times[i]
@@ -309,7 +309,7 @@ def test_median_stamps_trj(self):
         self.assertEqual(medianStamps1.get_height(), 5)
 
         # Compute the true median pixel for the middle of the track.
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         pix_values0 = []
         pix_values1 = []
         for i in range(self.imCount):
@@ -368,7 +368,7 @@ def test_mean_stamps_trj(self):
         self.assertEqual(meanStamp1.get_height(), 5)
 
         # Compute the true median pixel for the middle of the track.
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         pix_sum0 = 0.0
         pix_sum1 = 0.0
         pix_count0 = 0.0
@@ -605,7 +605,7 @@ def test_coadd_cpu(self):
         self.assertEqual(medianStamps[0].get_height(), 2 * params.radius + 1)
 
         # Compute the true summed and mean pixels for all of the pixels in the stamp.
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         for stamp_x in range(2 * params.radius + 1):
             for stamp_y in range(2 * params.radius + 1):
                 x_offset = stamp_x - params.radius
@@ -656,7 +656,7 @@ def test_coadd_gpu(self):
         self.assertEqual(medianStamps[0].get_height(), 2 * params.radius + 1)
 
         # Compute the true summed and mean pixels for all of the pixels in the stamp.
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         for stamp_x in range(2 * params.radius + 1):
             for stamp_y in range(2 * params.radius + 1):
                 x_offset = stamp_x - params.radius
@@ -702,7 +702,7 @@ def test_coadd_cpu_use_inds(self):
         meanStamps = self.search.get_coadded_stamps([self.trj, self.trj], inds, params, False)
 
         # Compute the true summed and mean pixels for all of the pixels in the stamp.
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         for stamp_x in range(2 * params.radius + 1):
             for stamp_y in range(2 * params.radius + 1):
                 x_offset = stamp_x - params.radius
@@ -751,7 +751,7 @@ def test_coadd_gpu_use_inds(self):
         meanStamps = self.search.get_coadded_stamps([self.trj, self.trj], inds, params, True)
 
         # Compute the true summed and mean pixels for all of the pixels in the stamp.
-        times = self.stack.get_times()
+        times = self.stack.build_zeroed_times()
         for stamp_x in range(2 * params.radius + 1):
             for stamp_y in range(2 * params.radius + 1):
                 x_offset = stamp_x - params.radius