{
 "slug": "friedrich-megalith-1802-03-19",
 "object": {
  "artist": "Caspar David Friedrich",
  "title": "Tree Study with Two Views of the Megalithic Tomb near Gützkow",
  "holder": "Wallraf-Richartz-Museum & Fondation Corboud, Cologne",
  "accession": "1934/10 verso",
  "catalogue": "Grummt 296 verso",
  "medium": "Pencil",
  "date_basis": "Published scholarly date, indexed excerpt; original date inscription not inspected",
  "date_inscription": null,
  "date_inscription_reason": "Date not visible in the available detail; full-sheet scan and Grummt entry unavailable",
  "measurement_notes": [
   "16 Fuß",
   "11 Fuß"
  ],
  "measurement_notes_status": "Numbers visible in the inspected detail; expanded German unit follows the published transcription linked below, not a diplomatic transcription of the handwriting",
  "conflicting_date": "1801 in the joint museum chronicle"
 },
 "window": {
  "start": "1802-03-19",
  "end": "1802-03-19",
  "days": 1,
  "basis": "Verwiebe (2024), pp. 83–84, fig. 27; same day requested in the brief",
  "interpretation": "Date of the field study as reported in scholarship; not a date for later painted skies"
 },
 "place": {
  "name": "Gützkow",
  "lat": 53.9378689,
  "lon": 13.4100305,
  "precision": "Town reference point; exact destroyed tomb site not established"
 },
 "station": {
  "name": "Berlin inner city",
  "id": "PANGAEA.869767 / Berlin_inner_City",
  "lat": 52.506,
  "lon": 13.39744,
  "km_to_guetzkow": 159,
  "position_caveat": "Reference point for a changing inner-city series, not a verified 1802 instrument position",
  "variable": "Published daily mean air temperature, °C",
  "coverage_start": "1766-01-01",
  "coverage_end": "1934-12-31"
 },
 "series": [
  {
   "date": "1802-03-19",
   "mean_c": 8.0
  }
 ],
 "candidates": {
  "stockholm": {
   "date": "1802-03-19",
   "raw_mean_c": 7.0,
   "homogenized_mean_c": 7.0,
   "adjusted_mean_c": 7.0,
   "source_id": 1,
   "lat": 59.365893,
   "lon": 18.058259,
   "km_to_guetzkow": 667,
   "first_date": "1756-01-01",
   "last_date": "2026-10-06",
   "decision": "Day confirmed; too distant to identify Gützkow weather"
  },
  "uppsala": {
   "date": "1802-03-19",
   "observed_series_mean_c": 6.5,
   "corrected_mean_c": 5.8,
   "source_id": 1,
   "decision": "Day confirmed; retained as a distant candidate, not used on the page"
  },
  "lund": {
   "target_month": null,
   "reason": "1802-03 absent in parsed monthly download; not evidence of no manuscript"
  },
  "greifswald": {
   "dwd_id": "01757",
   "first_date": "1898-03-01",
   "target_day": null,
   "reason": "DWD daily archive starts after target; earlier university register not obtained"
  },
  "copenhagen": {
   "target_day": null,
   "reason": "Historical compilation reports many missing March 1802 observations; exact day not verified"
  }
 },
 "quotes": {
  "date": {
   "text": "19. März 1802",
   "source": "date-literature",
   "type": "published_date"
  },
  "witness": {
   "text": "lag ich oben auf dem Decksteine und rauchte ein Pfeifchen",
   "source": "witness",
   "type": "Quistorp recollection reported by Schildener in 1828; modern institutional republication"
  }
 },
 "unresolved": {
  "local_temperature": null,
  "local_rain": null,
  "local_cloud": null,
  "local_wind": null,
  "local_snow_cover": null,
  "sketch_hour": null,
  "climate_rank": null,
  "reason": "No authenticated local weather record for the sketching day; no weather inferred from the image or reclining pose"
 },
 "receipts": {
  "museum": {
   "file": "friedrich-megalith-1802-03-19/museum-chronicle.html",
   "url": "https://cdfriedrich.de/en/chronicle/huenengrab-im-herbst/",
   "title": "Holger Birkholz, joint museum chronicle, Megalithic Tomb in Autumn, note 5",
   "license": "Joint museum chronicle; brief quotation/paraphrase; no image reuse",
   "sha256": "3f1868b7a4f4ba8fde730cdedb45154e4d93ed91b3a553b96fa23c8726641779",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "witness": {
   "file": "friedrich-megalith-1802-03-19/archaeology.html",
   "url": "https://www.kulturwerte-mv.de/Landesarchaeologie/Fund-des-Monats/Bisherige-Beitr%C3%A4ge/2026-01-huenengrab-im-schnee/",
   "title": "Landesamt für Kultur und Denkmalpflege Mecklenburg-Vorpommern, January 2026: Schildener’s report of Quistorp",
   "license": "Public state archaeology account; short attributed quotation; no image reuse",
   "sha256": "4c5e45638f97bb1ac0113dabd882e2c4d14f3796174aa7e727ec7348febacaf0",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "image-rights": {
   "file": "friedrich-megalith-1802-03-19/image-rights.html",
   "url": "https://commons.wikimedia.org/wiki/File:SigridHinz269.jpg",
   "title": "Wikimedia Commons, SigridHinz269.jpg, rights and scope",
   "license": "Commons metadata CC BY-SA; inspect image-specific PD declaration before downloading image",
   "sha256": "a1dee4e8f947b1d26a5a1d4b840b2904f23f21481cb940b1f60ede7995303188",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "image": {
   "file": "friedrich-megalith-1802-03-19/drawing.jpg",
   "url": "https://upload.wikimedia.org/wikipedia/commons/1/12/SigridHinz269.jpg",
   "title": "Friedrich, Gützkow tomb with Quistorp (detail), via Wikimedia Commons",
   "license": "Public domain, Public Domain Mark 1.0 in cached Commons file page; faithful scan; Friedrich died 1840",
   "sha256": "7fef6bb1ff3a02978a4bacc0f2a08c80d352f29909f2eff11fed770ab0581291",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "place": {
   "file": "friedrich-megalith-1802-03-19/guetzkow-place.json",
   "url": "https://nominatim.openstreetmap.org/search?q=G%C3%BCtzkow&format=json&limit=1",
   "title": "OpenStreetMap, Gützkow town reference point",
   "license": "ODbL 1.0 OpenStreetMap contributors; town reference point only",
   "sha256": "dde09e2f2fee9ee7d662a1937484a03b66618f2c9ca9f8a79810b1717155a628",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "stockholm": {
   "file": "friedrich-megalith-1802-03-19/stockholm-daily.csv",
   "url": "https://bolin.su.se/data/data/stockholm_daily_mean_temperature.csv",
   "title": "Bolin Centre, Stockholm daily mean temperatures, Anders Moberg",
   "license": "ODC-By, Anders Moberg, Bolin Centre Database",
   "sha256": "c240ae8d6f0a8888b909e3618bd004a818df90980392a086de83a5a61039c422",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "stockholm-meta": {
   "file": "friedrich-megalith-1802-03-19/stockholm-metadata.html",
   "url": "https://bolin.su.se/data/stockholm-historical-daily-temperature-2",
   "title": "Bolin Centre, documentation for Stockholm daily temperatures",
   "license": "ODC-By dataset metadata",
   "sha256": "5d44d4925722d82b41310a490ccb3f794c487b12fd1e61b5c637d3969cd65cee",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "uppsala": {
   "file": "friedrich-megalith-1802-03-19/uppsala.zip",
   "url": "https://www.smhi.se/download/18.53cdce23194f389da053a4e/1740398333056/uppsala_tm_1722-2022.zip",
   "title": "SMHI / Hans Bergström, Uppsala daily series 1722–2022",
   "license": "SMHI open data, Hans Bergström Uppsala University; CC BY 4.0",
   "sha256": "de4e7891c1a71257ca6f5dc3d1ae03326b766621f2eb169d4c3aa1d7b274726d",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "uppsala-meta": {
   "file": "friedrich-megalith-1802-03-19/uppsala-metadata.html",
   "url": "https://www.smhi.se/data/temperatur-och-vind/temperatur/uppsalas-temperaturserie",
   "title": "SMHI, Uppsala series documentation",
   "license": "SMHI open data documentation; CC BY 4.0",
   "sha256": "f4831d045035f6ecf9d98591d94d01003c6a80c3e195eea3743a949fce7c8415",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "copenhagen": {
   "file": "friedrich-megalith-1802-03-19/copenhagen-history.html",
   "url": "https://user-9y8ca5x.cld.bz/MeteorologiskeObservationerKobenhavn",
   "title": "V. Willaume-Jantzen, Meteorologiske Observationer i Kjøbenhavn (1896), p. 6",
   "license": "Public-domain historical meteorological report, 1896",
   "sha256": "0df690b5e8eeb30d8a098f2325dd51d736e0e6eb93c685a66a058eec0f8489e8",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "local-search": {
   "file": "friedrich-megalith-1802-03-19/greifswald-observers.html",
   "url": "https://share.greifswald.de/de/urlaub-kultur/sehenswuerdigkeiten/backsteingotik/fangenturm/",
   "title": "City of Greifswald, Fangenturm and the university observatory",
   "license": "City of Greifswald institutional history, research cache",
   "sha256": "fc0c907defda4337d20dab856eb157a54df5e6c33c97261b905188dcb884db4f",
   "retrieved_at": "2026-10-08",
   "kind": "download"
  },
  "berlin": {
   "file": "friedrich-megalith-1802-03-19/berlin-daily.tab",
   "url": "https://doi.pangaea.de/10.1594/PANGAEA.869767?format=textfile",
   "title": "Kadow, Wentzel, Jaekel, Bahlo and Cubasch (2016), Berlin Climate Record: daily mean temperature, 1766–1934",
   "license": "CC BY-SA 3.0; PANGAEA. Berlin-derived data and chart shared under the same licence",
   "sha256": "c58698c3da82e2dfc370474f466009bd68a649ed936873b15b9f25e6d725d269",
   "retrieved_at": "2026-10-08",
   "kind": "reused_download",
   "note": "Reused identical bytes from T93 cache; original retrieval 8 October 2026 UTC."
  },
  "dwd": {
   "file": "friedrich-megalith-1802-03-19/dwd-daily-stations.txt",
   "url": "https://opendata.dwd.de/climate_environment/CDC/observations_germany/climate/daily/kl/historical/KL_Tageswerte_Beschreibung_Stationen.txt",
   "title": "Deutscher Wetterdienst, daily climate station inventory (coverage check)",
   "license": "CC BY 4.0, Deutscher Wetterdienst; cached terms dated May 2024",
   "sha256": "dcfd7322e4ae3ddb9cef2619f2034b57945315a81ae64e3913daf8096bc81c7b",
   "retrieved_at": "2026-10-08",
   "kind": "reused_download",
   "note": "Reused identical bytes from T93 cache; original retrieval 8 October 2026 UTC."
  },
  "lund": {
   "file": "friedrich-megalith-1802-03-19/lund-monthly.csv",
   "url": "https://opendata-download-metobs.smhi.se/api/version/latest/parameter/22/station/53430/period/corrected-archive/data.csv",
   "title": "SMHI, Lund 53430, monthly mean air temperature, corrected archive (coverage check)",
   "license": "SMHI open data; CC BY 4.0, attribution SMHI",
   "sha256": "a3efc3fe42bb13d06841bef8b49cb6ca30db5c6c38763ddc03f376f5aef93108",
   "retrieved_at": "2026-10-08",
   "kind": "reused_download",
   "note": "Reused identical bytes from T93 cache; original retrieval 8 October 2026 UTC."
  },
  "date-literature": {
   "file": "friedrich-megalith-1802-03-19/verwiebe-date-search.json",
   "url": "https://ahnp.ub.uni-heidelberg.de/journals/jbm/issue/download/7454/1370",
   "title": "Birgit Verwiebe, An der Grenze der Sichtbarkeit, Jahrbuch der Berliner Museen 65 (2024), pp. 83–84",
   "license": "Copyright scholarly text; short quotation and attributed paraphrase only",
   "sha256": "c14eda1e46f403a07da8dfe1471aedfd902dca3e2446060e9622df99dcd8d5f7",
   "retrieved_at": "2026-10-08",
   "kind": "indexed_excerpt",
   "note": "Saved search-service excerpt of the indexed article. Full PDF returned an access challenge; neither scan nor date handwriting was inspected."
  },
  "inscription-review": {
   "file": "friedrich-megalith-1802-03-19/inscription-review.json",
   "url": "https://commons.wikimedia.org/wiki/File:SigridHinz269.jpg",
   "title": "Nephos inspection of the available image detail",
   "license": "Nephos research record, CC BY 4.0",
   "sha256": "e28b18024c4539b67693611d63a7918e4200947d3ae92212823596fbf7000473",
   "retrieved_at": "2026-10-08",
   "kind": "local_review",
   "note": "Measurement notes normalized; date inscription remains null. Committed copy in window-engine/evidence/friedrich-megalith-1802-03-19/."
  }
 }
}