diff --git a/py/desisurvey/ephem.py b/py/desisurvey/ephem.py
index a0a1a9d..0b0a165 100644
--- a/py/desisurvey/ephem.py
+++ b/py/desisurvey/ephem.py
@@ -23,12 +23,10 @@
 import desisurvey.tiles
 
 
-# Date range 2019-2025 for tabulated ephemerides.
-# This range is chosen large enough to cover commissioning,
-# survey validation and the 5-year main survey, so should
-# not normally need to be changed, except for testing.
+# Date range 2019-2029 for tabulated ephemerides.
+# This range is intended to cover out through the DESI extension.
 START_DATE = datetime.date(2019, 1, 1)
-STOP_DATE = datetime.date(2027, 12, 31)
+STOP_DATE = datetime.date(2029, 12, 31)
 
 _ephem = None
 
diff --git a/py/desisurvey/plan.py b/py/desisurvey/plan.py
index ba60250..18234ac 100644
--- a/py/desisurvey/plan.py
+++ b/py/desisurvey/plan.py
@@ -9,6 +9,8 @@
 
 import astropy.table
 import astropy.io.fits
+from astropy.coordinates import SkyCoord
+from astropy import units as u
 
 import desiutil.log
 
@@ -512,6 +514,7 @@ def afternoon_plan(self, night):
             self.add_pending_tile(tileid)
         if self.tiles_lowpass:
             self.prefer_low_passnum()
+        self.require_program_dependencies()
         zeropriority = ((self.tile_status != 'unobs') &
                         (self.tile_available == 0))
         self.tile_priority[zeropriority] = 0
@@ -559,3 +562,24 @@ def prefer_low_passnum(self):
                     # unobserved, overlapping tiles with lower pass numbers.
                     mfree[idx] = 0
         self.tile_available[~mfree] = 0
+
+    def require_program_dependencies(self):
+        depends_on = self.tiles.program_dependencies()
+        config = desisurvey.config.Configuration()
+        tile_diameter = 2 * config.tile_radius()
+
+        for program in depends_on:
+            mprog = self.tiles.program_mask[program]
+            mtodo = ((self.tile_status != 'done') &
+                     (self.tiles.in_desi != 0))
+            otherprog = depends_on[program]
+            # tiles we still intend to do in the underlying program
+            motherprog = self.tiles.program_mask[otherprog] & mtodo
+            cprog = SkyCoord(self.tiles.tileRA[mprog]*u.deg,
+                             self.tiles.tileDEC[mprog]*u.deg)
+            cotherprog = SkyCoord(self.tiles.tileRA[motherprog]*u.deg,
+                                  self.tiles.tileDEC[motherprog]*u.deg)
+            idxo, idxp, _, _ = cprog.search_around_sky(cotherprog, tile_diameter)
+            mblocked = np.zeros(len(mprog), dtype='bool')
+            mblocked[np.flatnonzero(mprog)[idxp]] = True
+            self.tile_available[mblocked] = 0
diff --git a/py/desisurvey/plots.py b/py/desisurvey/plots.py
index 17dd6f5..061ae67 100644
--- a/py/desisurvey/plots.py
+++ b/py/desisurvey/plots.py
@@ -19,7 +19,8 @@
 
 # Color associated with each program in the functions below.
 program_color = {'DARK': 'black', 'GRAY': 'gray', 'BRIGHT': 'orange',
-                 'BACKUP': 'green'}
+                 'BACKUP': 'green', 'DARK1B': 'purple',
+                 'BRIGHT1B': 'red'}
 
 
 def plot_sky_passes(ra, dec, passnum, z, clip_lo=None, clip_hi=None,
diff --git a/py/desisurvey/scheduler.py b/py/desisurvey/scheduler.py
index ab14fa3..d1d73b7 100644
--- a/py/desisurvey/scheduler.py
+++ b/py/desisurvey/scheduler.py
@@ -213,10 +213,10 @@ def conditions_to_program(self, seeing, transparency, skylevel,
                 return 'BRIGHT'
         return 'BACKUP'
 
-    def select_program(self, mjd_now, ETC, verbose=False,
+    def current_conditions(self, mjd_now, ETC, verbose=False,
                        seeing=None, transparency=None, skylevel=None,
                        airmass=None, speed=None):
-        """Select program to observe now.
+        """Return current conditions, based on ephemerides or speed.
         """
         if mjd_now < self.night_changes[0]:
             if verbose:
@@ -248,7 +248,9 @@ def select_program(self, mjd_now, ETC, verbose=False,
             else:
                 mjd_program_end = self.night_changes[-1]
             return program, mjd_program_end
+
         # select program based on ephemerides, not conditions.
+        # we have not actually used this in DESI.
         idx = 0
         while ((idx + 1 < len(self.night_changes)) and
                (mjd_now >= self.night_changes[idx + 1])):
@@ -348,14 +350,15 @@ def next_tile(self, mjd_now, ETC, seeing, transp, skylevel, HA_sigma=15.,
         self.tile_sel = np.ones(self.tiles.ntiles, dtype=bool)
         if program is None:
             # Which program are we in?
-            program, mjd_program_end = self.select_program(
+            conditions, mjd_program_end = self.current_conditions(
                 mjd_now, ETC, verbose=verbose, seeing=seeing,
                 skylevel=skylevel, transparency=transp, speed=speed)
-            self.tile_sel &= self.tiles.allowed_in_conditions(program)
+            self.tile_sel &= self.tiles.allowed_in_conditions(conditions)
             if verbose:
                 self.log.info(
                     'Selecting a tile observable in {} conditions.'.format(
                         program))
+            program = conditions
         else:
             self.tile_sel &= self.tiles.program_mask[program]
             mjd_program_end = self.night_changes[-1]  # end of night?
diff --git a/py/desisurvey/scripts/surveyinit.py b/py/desisurvey/scripts/surveyinit.py
index 9139348..3d7ebfe 100644
--- a/py/desisurvey/scripts/surveyinit.py
+++ b/py/desisurvey/scripts/surveyinit.py
@@ -114,6 +114,9 @@ def parse(options=None):
     parser.add_argument(
         '--start', default=None, type=str,
         help='Use this start date instead of config.')
+    parser.add_argument(
+        '--stop', default=None, type=str,
+        help='Use this stop date instead of config.')
 
     if options is None:
         args = parser.parse_args()
@@ -163,7 +166,10 @@ def calculate_initial_plan(args):
         start = config.first_day()
     else:
         start = desisurvey.utils.get_date(args.start)
-    stop = config.last_day()
+    if args.stop is None:
+        stop = config.last_day()
+    else:
+        stop = desisurvey.utils.get_date(args.stop)
     assert start >= first and stop <= last
     hdr['START'] = start.isoformat()
     hdr['STOP'] = stop.isoformat()
diff --git a/py/desisurvey/scripts/surveymovie.py b/py/desisurvey/scripts/surveymovie.py
index df12787..d236a31 100644
--- a/py/desisurvey/scripts/surveymovie.py
+++ b/py/desisurvey/scripts/surveymovie.py
@@ -145,7 +145,7 @@ def __init__(self, exposures_path, start, stop, label, show_scores):
         self.tileid = self.tiles.tileID
         self.prognames = [p for p in self.tiles.programs]
         # if DARK and BRIGHT are names, put them first
-        for pname in ['BRIGHT', 'DARK']:
+        for pname in ['BRIGHT1B', 'DARK1B', 'BRIGHT', 'DARK']:
             if pname in self.prognames:
                 self.prognames.remove(pname)
                 self.prognames = [pname] + self.prognames
@@ -200,7 +200,7 @@ def init_figure(self, nightly, width=1920, height=1080, dpi=32):
         self.figure = plt.figure(
             frameon=False,figsize=(width / self.dpi, height / self.dpi),
             dpi=self.dpi)
-        grid = matplotlib.gridspec.GridSpec(2, 2)
+        grid = matplotlib.gridspec.GridSpec(3, 2)
         grid.update(left=0, right=1, bottom=0, top=0.97, hspace=0, wspace=0)
         axes = []
         self.labels = []
@@ -222,7 +222,7 @@ def init_figure(self, nightly, width=1920, height=1080, dpi=32):
         self.nowcolor = np.array([0., 0.7, 0., 1.])
         pcolors = desisurvey.plots.program_color
         progidx = 0
-        for row in range(2):
+        for row in range(3):
             for col in range(2):
                 # Create the axes for this program.
                 ax = plt.subplot(grid[row, col], facecolor=bgcolor)
@@ -230,7 +230,7 @@ def init_figure(self, nightly, width=1920, height=1080, dpi=32):
                 ax.set_yticks([])
                 axes.append(ax)
                 # Bottom-right corner is reserved for integrated progress plots.
-                if row == 1 and col == 1:
+                if row == 2 and col == 1:
                     ax.set_xlim(0, self.survey_weeks)
                     ax.set_ylim(0, 1)
                     ax.plot([0, self.survey_weeks], [0., 1.], 'w-')
@@ -249,7 +249,7 @@ def init_figure(self, nightly, width=1920, height=1080, dpi=32):
                     # e.g., for no-gray mode, where we have only two programs.
                     continue
                 ax.set_xlim(-55, 293)
-                ax.set_ylim(-20, 77)
+                ax.set_ylim(-30, 77)
                 # Draw label for this plot.
                 pname = self.prognames[progidx]
                 pc = pcolors[pname]
@@ -553,7 +553,8 @@ def update(iframe):
         animation = matplotlib.animation.FuncAnimation(
             animator.figure, update, init_func=init, blit=True, frames=nframes)
         writer = matplotlib.animation.writers['ffmpeg'](
-            bitrate=2400, fps=args.fps, metadata=dict(artist='surveymovie'))
+            bitrate=2400, fps=args.fps, codec='vp9',
+            metadata=dict(artist='surveymovie'))
         save_name = args.save + '.mp4'
         animation.save(save_name, writer=writer, dpi=animator.dpi)
         log.info('Saved {0}.'.format(save_name))
diff --git a/py/desisurvey/tiles.py b/py/desisurvey/tiles.py
index d101f30..6800f5e 100644
--- a/py/desisurvey/tiles.py
+++ b/py/desisurvey/tiles.py
@@ -242,6 +242,17 @@ def allowed_in_conditions(self, cond):
             res = res | (self.tileobsconditions == 'BRIGHT')
         return res
 
+    def program_dependencies(self):
+        depends_on = dict()
+        config = desisurvey.config.Configuration()
+        for program in config.programs.keys:
+            prognode = getattr(config.programs, program)
+            dependencies = getattr(prognode, 'depends_on', None)
+            if dependencies is not None:
+                depends_on[program] = dependencies()
+        return depends_on
+
+
     @property
     def overlapping(self):
         """Dictionary of tile overlap matrices.
@@ -350,11 +361,6 @@ def _calculate_neighbors(self):
                     # ignore self matches
                     continue
                 self._neighbors[rownum[ind1]].append(rownum[ind2])
-
-            for passnum in np.unique(self.tilepass[mprogram]):
-                m = (mprogram & (self.tilepass == passnum) &
-                     (self.in_desi != 0))
-                rownum = np.flatnonzero(m)
                 # self._neighbors: list of lists, giving tiles neighboring each
                 # tile