diff --git a/src/app/shared/astro/host-star-matching.spec.ts b/src/app/shared/astro/host-star-matching.spec.ts
index 6891d15..177d80c 100644
--- a/src/app/shared/astro/host-star-matching.spec.ts
+++ b/src/app/shared/astro/host-star-matching.spec.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest';
 
-import { ARCHIVE_ID_BASE, archiveStarId, buildStarNameIndex, normalizeStarName, resolveHostStarId } from './host-star-matching';
+import { ARCHIVE_EPOCH, ARCHIVE_ID_BASE, archiveStarId, buildStarNameIndex, CATALOGUE_EPOCH, normalizeStarName, resolveHostStarId } from './host-star-matching';
 import { propagateProperMotion, raDegDecDistanceToXyz } from './coordinates';
 import { StarRecord } from '../models/star.model';
 
@@ -81,13 +81,13 @@ describe('resolveHostStarId', () => {
       expect(id).toBe(80);
     });
 
-    // GJ 15 A's archive row sits at J2016, 46″ along its proper motion from Groombridge 34's
+    // GJ 15 A's archive row sits at J2015.5, 45″ along its proper motion from Groombridge 34's
     // J2000 place — and only 16″ from an unrelated Gaia entry. Nearest-to-the-published-point
-    // picks the interloper; carrying the query back the sixteen years must put the planets on
-    // the star that actually moved there.
+    // picks the interloper; carrying the query back the fifteen and a half years must put the
+    // planets on the star that actually moved there.
     it('picks the star the proper motion says the query is, not the entry nearest the published point', () => {
       const primary = star(90, 'Groombridge 34', 4.595364, 44.022955, 3.562);
-      const published = propagateProperMotion(4.595364, 44.022955, 2891.5, 411.9, 16);
+      const published = propagateProperMotion(4.595364, 44.022955, 2891.5, 411.9, 15.5);
       const interloper = star(91, 'Gaia DR3 385334196532776576', published.raDeg, published.decDeg + 16 / 3600, 3.563);
 
       const id = resolveHostStarId(
@@ -215,6 +215,17 @@ describe('resolveHostStarId', () => {
   });
 });
 
+describe('the archive epoch', () => {
+  it("carries Barnard's star from the archive's position to where Gaia DR3's goes, to a few milliarcseconds", () => {
+    // The archive publishes Gaia DR2's J2015.5 position and motion; DR3's is at J2016.
+    const archive = propagateProperMotion(269.4486144, 4.7379808, -802.803, 10362.5, CATALOGUE_EPOCH - ARCHIVE_EPOCH);
+    const dr3 = propagateProperMotion(269.44850252543836, 4.739420051112412, -801.5509783684709, 10362.394206546573, CATALOGUE_EPOCH - 2016);
+    const [a, b] = [archive, dr3].map(({ raDeg, decDeg }) => raDegDecDistanceToXyz(raDeg, decDeg, 1));
+    const separationArcsec = (Math.acos(Math.min(1, a.x * b.x + a.y * b.y + a.z * b.z)) * 180 * 3600) / Math.PI;
+    expect(separationArcsec).toBeLessThan(0.02);
+  });
+});
+
 describe('archiveStarId', () => {
   it('gives a host the same id whatever else the archive holds, inside the range left for it', () => {
     const kepler186 = archiveStarId('Kepler-186', new Set());
diff --git a/src/app/shared/astro/host-star-matching.ts b/src/app/shared/astro/host-star-matching.ts
index 2ffe684..e5283a0 100644
--- a/src/app/shared/astro/host-star-matching.ts
+++ b/src/app/shared/astro/host-star-matching.ts
@@ -80,15 +80,17 @@ export const HOST_TRANSVERSE_TOLERANCE_PC = 0.01;
 /**
  * The archive does not say which epoch a row's position is for, and they are demonstrably
  * mixed: alf Tau and GJ 273 publish J2000 (the raw position sits under an arcsecond from our
- * star, and carrying it back doubles the error), HD 133131 and TOI-2459 publish Gaia's J2016
- * (the carried-back position lands to 0.1″). So every query is tried at both ends — as
- * published, and carried back sixteen years with the archive's own proper motion — and a star
- * is judged on whichever is closer. Guessing one epoch picks companions: assume J2016 and
- * Aldebaran's planet lands on Gl 171.1B, assume J2000 and GJ 15 A's land on a Gaia entry
- * 15.9″ out.
+ * star, and carrying it back doubles the error), HD 133131 and TOI-2459 publish Gaia DR2's J2015.5
+ * (the carried-back position lands to 0.1″). DR2's, not DR3's J2016, although the archive names
+ * the DR3 source: Barnard's star, Teegarden's Star, TRAPPIST-1 and 66 of the 67 archive-placed
+ * stars moving over 100 mas a year equal their DR2 position to a milliarcsecond and none their
+ * DR3 one. So every query is tried at both ends — as published, and carried back fifteen and a
+ * half years with the archive's own proper motion — and a star is judged on whichever is closer.
+ * Guessing one epoch picks companions: assume the later one and Aldebaran's planet lands on Gl
+ * 171.1B, assume J2000 and GJ 15 A's land on a Gaia entry 15.9″ out.
  */
-const CATALOGUE_EPOCH = 2000.0;
-const ARCHIVE_LATEST_EPOCH = 2016.0;
+export const CATALOGUE_EPOCH = 2000.0;
+export const ARCHIVE_EPOCH = 2015.5;
 
 function knownMotion(masPerYear: number | undefined): number {
   return Number.isFinite(masPerYear) ? (masPerYear as number) : 0;
@@ -140,7 +142,7 @@ export function resolveHostStarId(
     // star would pass the direction test and the last one in array order would win.
     knownMotion(query.pmRaMasPerYear),
     knownMotion(query.pmDecMasPerYear),
-    CATALOGUE_EPOCH - ARCHIVE_LATEST_EPOCH
+    CATALOGUE_EPOCH - ARCHIVE_EPOCH
   );
   const carried = raDegDecDistanceToXyz(carriedBack.raDeg, carriedBack.decDeg, 1);
 
diff --git a/src/assets/data/stars.bin b/src/assets/data/stars.bin
index a28de6d..7dad89d 100644
Binary files a/src/assets/data/stars.bin and b/src/assets/data/stars.bin differ
diff --git a/tools/etl/fetchExoplanets.ts b/tools/etl/fetchExoplanets.ts
index 7b91288..7d1f1c0 100644
--- a/tools/etl/fetchExoplanets.ts
+++ b/tools/etl/fetchExoplanets.ts
@@ -2,7 +2,7 @@ import { createHash } from 'node:crypto';
 import { writeFileSync } from 'node:fs';
 
 import { propagateProperMotion, raDegDecDistanceToXyz } from '../../src/app/shared/astro/coordinates';
-import { archiveStarId, buildStarNameIndex, resolveHostStarId } from '../../src/app/shared/astro/host-star-matching';
+import { ARCHIVE_EPOCH, archiveStarId, buildStarNameIndex, CATALOGUE_EPOCH, resolveHostStarId } from '../../src/app/shared/astro/host-star-matching';
 import { temperatureToColorIndex } from '../../src/app/shared/astro/spectral';
 import { ExoplanetRecord } from '../../src/app/shared/models/exoplanet.model';
 import { isDesignation } from '../../src/app/shared/models/star-catalog';
@@ -87,12 +87,12 @@ const DISTANCE_ERRORS_CACHE_FILE = `exoplanet-archive-disterr-${createHash('sha1
 
 const ARCHIVE_SOURCE = 'exoplanet-archive';
 /**
- * The archive's positions are at Gaia's epoch, J2016, not the catalogue's J2000: of the 746
- * matched hosts moving over 100 mas a year, 741 sit nearer their star once carried back sixteen
- * years (a median 0.11″ from it, against 3.47″ as published). The matcher tries both epochs; a
- * star placed from the archive has to pick one.
+ * The archive's positions are at Gaia DR2's epoch, J2015.5, not the catalogue's J2000 (see
+ * `ARCHIVE_EPOCH`): of the 746 matched hosts moving over 100 mas a year, 741 sit nearer their star
+ * once carried back (a median 0.11″ from it, against 3.47″ as published). The matcher tries both
+ * epochs; a star placed from the archive has to pick one.
  */
-const ARCHIVE_TO_CATALOGUE_YEARS = 2000 - 2016;
+const ARCHIVE_TO_CATALOGUE_YEARS = CATALOGUE_EPOCH - ARCHIVE_EPOCH;
 /** As in `fetchStars`: faint, for a host the archive gives neither a V nor a G magnitude. */
 const UNKNOWN_MAGNITUDE = 15;