diff --git a/python/activator/middleware_interface.py b/python/activator/middleware_interface.py
index b97be87f..b204508c 100644
--- a/python/activator/middleware_interface.py
+++ b/python/activator/middleware_interface.py
@@ -430,6 +430,7 @@ def _export_refcats(self, center, radius):
         # with another solution ASAP.
         possible_refcats = ["gaia", "panstarrs", "gaia_dr2_20200414", "ps1_pv3_3pi_20170110",
                             "atlas_refcat2_20220201", "gaia_dr3_20230707"]
+        _log.debug("Searching for refcats in %s...", shard_ids)
         refcats = set(_filter_datasets(
                       self.central_butler, self.butler,
                       possible_refcats,
@@ -481,6 +482,7 @@ def _export_skymap_and_templates(self, center, detector, wcs, filter):
         # specified as a class kwarg, so that we only load one here?
         # TODO: alternately, we need to extract it from the pipeline? (best?)
         try:
+            _log.debug("Searching for templates in tract %d, patches %s...", tract.tract_id, patches_str)
             templates = set(_filter_datasets(
                 self.central_butler, self.butler,
                 "*Coadd",
diff --git a/python/activator/visit.py b/python/activator/visit.py
index 7d981346..d42dc8f6 100644
--- a/python/activator/visit.py
+++ b/python/activator/visit.py
@@ -54,9 +54,12 @@ class Dome(enum.IntEnum):
         OPEN = 2
         EITHER = 3
 
-    salIndex: int               # this maps to an instrument
+    # script queue that generated the event. One queue usually runs one telescope, but they can switch
+    salIndex: int
     scriptSalIndex: int
-    groupId: str                # observatory-specific ID; not the same as visit number
+    # Observatory-specific ID. Same as Butler's group_name, not the same as
+    # Butler's group_id or visit number
+    groupId: str
     coordinateSystem: CoordSys  # coordinate system of position
     # (ra, dec) or (az, alt) in degrees. Use compare=False to exclude from hash.
     position: list[float] = field(compare=False)
@@ -104,11 +107,11 @@ def get_bare_visit(self):
 @dataclass(frozen=True, kw_only=True)
 class SummitVisit(BareVisit):
     # Extra fields are in the NextVisit messages from the summit
-    private_efdStamp: float = 0.0
+    private_efdStamp: float = 0.0  # time of visit publication; UTC in unix seconds
     private_kafkaStamp: float = 0.0
     private_identity: str = "ScriptQueue"
     private_revCode: str = "c9aab3df"
     private_origin: int = 0
-    private_seqNum: int = 0
+    private_seqNum: int = 0        # counts script calls since queue start. Not the same as Butler seq_num
     private_rcvStamp: float = 0.0
-    private_sndStamp: float = 0.0
+    private_sndStamp: float = 0.0  # time of visit publication; TAI in unix seconds