{
  "site": {
    "horizonProfile": {
      "observerElevM": 1389,
      "profile": {
        "N": 0,
        "NNE": 0,
        "NE": 0,
        "ENE": 0,
        "E": 0.4,
        "ESE": 1,
        "SE": 0.5,
        "SSE": 0,
        "S": 0,
        "SSW": 0,
        "SW": 0,
        "WSW": 0,
        "W": 0,
        "WNW": 0.6,
        "NW": 0.4,
        "NNW": 1.3
      },
      "south": {
        "worst": 0.5,
        "mean": 0.1,
        "dueSouth": 0
      },
      "core": {
        "coreAltitudeDeg": 16.4,
        "terrainDeg": 0.5,
        "marginDeg": 15.9,
        "verdict": "clear"
      },
      "computed": "2026-08-24",
      "parts": null
    },
    "id": "devils-tower",
    "name": "Devils Tower National Monument",
    "region": "Crook County, WY",
    "timezone": "America/Denver",
    "darkSkyPark": false,
    "kind": "area",
    "kindNote": "Every figure on this page is computed at Joyner Ridge, which is the spot inside the monument the park itself points stargazers to. The monument is small, so the sky over the rest of it is much the same, but the horizon and the terrain are the ridge.",
    "insideNote": "Go to Joyner Ridge. It is the spot the Park Service itself points stargazers to, it is a short drive from the entrance station, and the directions are in the access notes below.",
    "mergedFrom": null,
    "bortle": null,
    "skyBrightness": null,
    "skyBrightnessFrom": null,
    "darknessNote": "Not measured. Nobody has published a sky-brightness reading for the monument that this site can point at. What is objective is that the nearest town of any size is 80 miles away.",
    "lat": 44.5902,
    "lng": -104.7146,
    "ground": {
      "roads": "The road surface is pretty good. Wildlife roams, so be careful.",
      "gate": "Nobody is on duty at the gate.",
      "parking": "A vehicle can sit overnight only in a registered campsite at the Belle Fourche River Campground. Overnight parking is not permitted in the visitor center or trailhead lots.",
      "cell": "It works, but it is very weak."
    },
    "groundBy": "Daniel Milks, My XO Adventures.",
    "horizon": "Joyner Ridge, which the Park Service names as the best place to stargaze in the monument: wide open, little light pollution, and the Tower in view. This is the Park Service's assessment and not a visit by anyone from this site.",
    "access": "Joyner Ridge is reached from the entrance station by taking the park road about 2 miles, turning left onto the signed gravel road, following it about 0.3 miles, then turning right into a small gravel parking area. The parking area is unpaved but fairly level. RVs and motorcycles are not recommended on the gravel road. Visiting at night to hike or stargaze is permitted, but parking or camping overnight at Joyner Ridge is not. The Joyner Ridge Trail is a 1.5-mile loop, is not maintained in winter, and commonly holds packed snow and ice from December through April.",
    "accessUnknown": [],
    "contact": null,
    "sources": [
      {
        "label": "NPS, Stargaze at Joyner Ridge",
        "url": "https://www.nps.gov/thingstodo/stargaze-joyner-ridge.htm"
      },
      {
        "label": "NPS, Hike Joyner Ridge Trail",
        "url": "https://www.nps.gov/thingstodo/hike-joyner-ridge-trail.htm"
      },
      {
        "label": "NPS, Devils Tower night sky viewing",
        "url": "https://www.nps.gov/deto/planyourvisit/night-sky-viewing.htm"
      }
    ],
    "verified": "2026-08-24",
    "notes": "Iconic foreground for astrophotography.",
    "lightSource": null
  },
  "days": 14,
  "generatedAt": "2026-09-18T01:55:25.228Z",
  "weather": {
    "source": "Open-Meteo",
    "error": null,
    "nightsCovered": 14,
    "nightsTotal": 14,
    "note": "Cloud forecast covers every night shown"
  },
  "headline": "Nothing outstanding in the next 14 nights. Monday September 21 is the least compromised.",
  "best": {
    "site": "devils-tower",
    "siteName": "Devils Tower National Monument",
    "region": "Crook County, WY",
    "date": "2026-09-21",
    "score": 65,
    "verdict": "Fair",
    "headline": "Workable. Moon down after 2:19am, clear skies.",
    "headlineLead": "Workable",
    "headlineDetail": "moon down after 2:19am, clear skies",
    "milkyWay": {
      "visible": true,
      "maxAltitudeDeg": 11.6,
      "hoursUseful": 0.33,
      "bestAt": "8:39pm",
      "note": "Milky Way core up to 11.6°, high enough to be worth it for 0h20m"
    },
    "window": {
      "darkFrom": "8:39pm",
      "darkTo": "5:08am",
      "hours": 8.5,
      "bestFrom": "2:19am",
      "bestTo": "5:08am"
    },
    "factors": [
      {
        "key": "cloud",
        "name": "Cloud",
        "score": 83,
        "weight": 32,
        "note": "14% cloud, essentially clear"
      },
      {
        "key": "moon",
        "name": "Moon",
        "score": 66,
        "weight": 26,
        "note": "waxing gibbous at 80%, sets 2:19am, dark after that"
      },
      {
        "key": "darkness",
        "name": "Darkness",
        "score": 94,
        "weight": 16,
        "note": "8h30m of astronomical darkness, 8:39pm–5:08am"
      },
      {
        "key": "transparency",
        "name": "Transparency",
        "score": 5,
        "weight": 10,
        "note": "Dewpoint spread 2.5°C, some haze possible"
      },
      {
        "key": "targets",
        "name": "Targets",
        "score": 39,
        "weight": 16,
        "note": "Milky Way core up to 11.6°, high enough to be worth it for 0h20m"
      }
    ],
    "weatherBacked": true,
    "confidence": "full",
    "dataSources": {
      "astronomy": "SunCalc (local computation)",
      "weather": "Open-Meteo"
    },
    "weekday": "Monday",
    "isWeekend": false
  },
  "bestWeekend": {
    "site": "devils-tower",
    "siteName": "Devils Tower National Monument",
    "region": "Crook County, WY",
    "date": "2026-09-18",
    "score": 47,
    "verdict": "Poor",
    "headline": "Poor conditions. Moon down after 11:10pm, 100% cloud.",
    "headlineLead": "Poor conditions",
    "headlineDetail": "moon down after 11:10pm, 100% cloud",
    "milkyWay": {
      "visible": true,
      "maxAltitudeDeg": 12,
      "hoursUseful": 0.49,
      "bestAt": "8:45pm",
      "note": "Milky Way core up to 12°, high enough to be worth it for 0h29m"
    },
    "window": {
      "darkFrom": "8:45pm",
      "darkTo": "5:04am",
      "hours": 8.32,
      "bestFrom": "11:10pm",
      "bestTo": "5:04am"
    },
    "factors": [
      {
        "key": "cloud",
        "name": "Cloud",
        "score": 0,
        "weight": 32,
        "note": "100% cloud, mostly high cirrus, thin to the eye but ruinous for photography"
      },
      {
        "key": "moon",
        "name": "Moon",
        "score": 96,
        "weight": 26,
        "note": "first quarter at 54%, sets 11:10pm, dark after that"
      },
      {
        "key": "darkness",
        "name": "Darkness",
        "score": 92,
        "weight": 16,
        "note": "8h19m of astronomical darkness, 8:45pm–5:04am"
      },
      {
        "key": "transparency",
        "name": "Transparency",
        "score": 3,
        "weight": 10,
        "note": "Dewpoint spread 2.3°C, some haze possible"
      },
      {
        "key": "targets",
        "name": "Targets",
        "score": 43,
        "weight": 16,
        "note": "Milky Way core up to 12°, high enough to be worth it for 0h29m"
      }
    ],
    "weatherBacked": true,
    "confidence": "full",
    "dataSources": {
      "astronomy": "SunCalc (local computation)",
      "weather": "Open-Meteo"
    },
    "weekday": "Friday",
    "isWeekend": true
  },
  "nights": [
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-17",
      "score": 51,
      "verdict": "Fair",
      "headline": "Workable. Moon down after 10:17pm, 85% cloud.",
      "headlineLead": "Workable",
      "headlineDetail": "moon down after 10:17pm, 85% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 12.2,
        "hoursUseful": 0.49,
        "bestAt": "8:47pm",
        "note": "Milky Way core up to 12.2°, high enough to be worth it for 0h29m"
      },
      "window": {
        "darkFrom": "8:47pm",
        "darkTo": "5:03am",
        "hours": 8.27,
        "bestFrom": "10:17pm",
        "bestTo": "5:03am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 12,
          "weight": 32,
          "note": "85% cloud, overcast"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 98,
          "weight": 26,
          "note": "first quarter at 45%, sets 10:17pm, dark after that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 92,
          "weight": 16,
          "note": "8h16m of astronomical darkness, 8:47pm–5:03am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 0,
          "weight": 10,
          "note": "Dewpoint spread 1.1°C, fog or heavy haze likely"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 43,
          "weight": 16,
          "note": "Milky Way core up to 12.2°, high enough to be worth it for 0h29m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Thursday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-18",
      "score": 47,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon down after 11:10pm, 100% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon down after 11:10pm, 100% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 12,
        "hoursUseful": 0.49,
        "bestAt": "8:45pm",
        "note": "Milky Way core up to 12°, high enough to be worth it for 0h29m"
      },
      "window": {
        "darkFrom": "8:45pm",
        "darkTo": "5:04am",
        "hours": 8.32,
        "bestFrom": "11:10pm",
        "bestTo": "5:04am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 0,
          "weight": 32,
          "note": "100% cloud, mostly high cirrus, thin to the eye but ruinous for photography"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 96,
          "weight": 26,
          "note": "first quarter at 54%, sets 11:10pm, dark after that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 92,
          "weight": 16,
          "note": "8h19m of astronomical darkness, 8:45pm–5:04am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 3,
          "weight": 10,
          "note": "Dewpoint spread 2.3°C, some haze possible"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 43,
          "weight": 16,
          "note": "Milky Way core up to 12°, high enough to be worth it for 0h29m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Friday",
      "isWeekend": true
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-19",
      "score": 45,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon down after 12:08am, 100% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon down after 12:08am, 100% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 11.9,
        "hoursUseful": 0.48,
        "bestAt": "8:43pm",
        "note": "Milky Way core up to 11.9°, high enough to be worth it for 0h29m"
      },
      "window": {
        "darkFrom": "8:43pm",
        "darkTo": "5:06am",
        "hours": 8.38,
        "bestFrom": "12:08am",
        "bestTo": "5:06am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 0,
          "weight": 32,
          "note": "100% cloud, mostly high cirrus, thin to the eye but ruinous for photography"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 90,
          "weight": 26,
          "note": "first quarter at 64%, sets 12:08am, dark after that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 93,
          "weight": 16,
          "note": "8h23m of astronomical darkness, 8:43pm–5:06am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 0,
          "weight": 10,
          "note": "Dewpoint spread 1.4°C, fog or heavy haze likely"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 42,
          "weight": 16,
          "note": "Milky Way core up to 11.9°, high enough to be worth it for 0h29m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Saturday",
      "isWeekend": true
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-20",
      "score": 43,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon down after 1:11am, 100% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon down after 1:11am, 100% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 11.7,
        "hoursUseful": 0.49,
        "bestAt": "8:41pm",
        "note": "Milky Way core up to 11.7°, high enough to be worth it for 0h29m"
      },
      "window": {
        "darkFrom": "8:41pm",
        "darkTo": "5:07am",
        "hours": 8.44,
        "bestFrom": "1:11am",
        "bestTo": "5:07am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 0,
          "weight": 32,
          "note": "100% cloud, mostly high cirrus, thin to the eye but ruinous for photography"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 81,
          "weight": 26,
          "note": "waxing gibbous at 72%, sets 1:11am, dark after that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 94,
          "weight": 16,
          "note": "8h26m of astronomical darkness, 8:41pm–5:07am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 0,
          "weight": 10,
          "note": "Dewpoint spread 1.9°C, fog or heavy haze likely"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 42,
          "weight": 16,
          "note": "Milky Way core up to 11.7°, high enough to be worth it for 0h29m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Sunday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-21",
      "score": 65,
      "verdict": "Fair",
      "headline": "Workable. Moon down after 2:19am, clear skies.",
      "headlineLead": "Workable",
      "headlineDetail": "moon down after 2:19am, clear skies",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 11.6,
        "hoursUseful": 0.33,
        "bestAt": "8:39pm",
        "note": "Milky Way core up to 11.6°, high enough to be worth it for 0h20m"
      },
      "window": {
        "darkFrom": "8:39pm",
        "darkTo": "5:08am",
        "hours": 8.5,
        "bestFrom": "2:19am",
        "bestTo": "5:08am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 83,
          "weight": 32,
          "note": "14% cloud, essentially clear"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 66,
          "weight": 26,
          "note": "waxing gibbous at 80%, sets 2:19am, dark after that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 94,
          "weight": 16,
          "note": "8h30m of astronomical darkness, 8:39pm–5:08am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 5,
          "weight": 10,
          "note": "Dewpoint spread 2.5°C, some haze possible"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 39,
          "weight": 16,
          "note": "Milky Way core up to 11.6°, high enough to be worth it for 0h20m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Monday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-22",
      "score": 35,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon down after 3:26am, 85% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon down after 3:26am, 85% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 11.5,
        "hoursUseful": 0.32,
        "bestAt": "8:36pm",
        "note": "Milky Way core up to 11.5°, high enough to be worth it for 0h19m"
      },
      "window": {
        "darkFrom": "8:36pm",
        "darkTo": "5:10am",
        "hours": 8.55,
        "bestFrom": "3:26am",
        "bestTo": "5:10am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 0,
          "weight": 32,
          "note": "85% cloud, mostly high cirrus, thin to the eye but ruinous for photography"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 47,
          "weight": 26,
          "note": "waxing gibbous at 88%, sets 3:26am, dark after that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 95,
          "weight": 16,
          "note": "8h33m of astronomical darkness, 8:36pm–5:10am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 9,
          "weight": 10,
          "note": "Dewpoint spread 2.9°C, some haze possible"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 39,
          "weight": 16,
          "note": "Milky Way core up to 11.5°, high enough to be worth it for 0h19m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Tuesday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-23",
      "score": 62,
      "verdict": "Fair",
      "headline": "Workable. Moon down after 4:34am, clear skies.",
      "headlineLead": "Workable",
      "headlineDetail": "moon down after 4:34am, clear skies",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 11.3,
        "hoursUseful": 0.32,
        "bestAt": "8:34pm",
        "note": "Milky Way core up to 11.3°, high enough to be worth it for 0h19m"
      },
      "window": {
        "darkFrom": "8:34pm",
        "darkTo": "5:11am",
        "hours": 8.61,
        "bestFrom": "4:34am",
        "bestTo": "5:11am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 93,
          "weight": 32,
          "note": "5% cloud, essentially clear"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 23,
          "weight": 26,
          "note": "waxing gibbous at 93%, sets 4:34am, dark after that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 96,
          "weight": 16,
          "note": "8h37m of astronomical darkness, 8:34pm–5:11am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 47,
          "weight": 10,
          "note": "Dewpoint spread 6.7°C, some haze possible"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 38,
          "weight": 16,
          "note": "Milky Way core up to 11.3°, high enough to be worth it for 0h19m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Wednesday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-24",
      "score": 60,
      "verdict": "Fair",
      "headline": "Workable. Moon up all night, clear skies.",
      "headlineLead": "Workable",
      "headlineDetail": "moon up all night, clear skies",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 11.2,
        "hoursUseful": 0.32,
        "bestAt": "8:32pm",
        "note": "Milky Way core up to 11.2°, high enough to be worth it for 0h19m"
      },
      "window": {
        "darkFrom": "8:32pm",
        "darkTo": "5:12am",
        "hours": 8.67,
        "bestFrom": "8:32pm",
        "bestTo": "5:12am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 95,
          "weight": 32,
          "note": "4% cloud, essentially clear"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 0,
          "weight": 26,
          "note": "full moon at 98%, up the whole window, washing out faint targets"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 96,
          "weight": 16,
          "note": "8h40m of astronomical darkness, 8:32pm–5:12am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 84,
          "weight": 10,
          "note": "Dewpoint spread 10.4°C, dry and steady air"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 38,
          "weight": 16,
          "note": "Milky Way core up to 11.2°, high enough to be worth it for 0h19m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Thursday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-25",
      "score": 45,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon up all night, 22% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon up all night, 22% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 11,
        "hoursUseful": 0.32,
        "bestAt": "8:30pm",
        "note": "Milky Way core up to 11°, high enough to be worth it for 0h19m"
      },
      "window": {
        "darkFrom": "8:30pm",
        "darkTo": "5:14am",
        "hours": 8.72,
        "bestFrom": "8:30pm",
        "bestTo": "5:14am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 72,
          "weight": 32,
          "note": "22% cloud cover, 21% of it high"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 0,
          "weight": 26,
          "note": "full moon at 100%, up the whole window, washing out faint targets"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 97,
          "weight": 16,
          "note": "8h43m of astronomical darkness, 8:30pm–5:14am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 6,
          "weight": 10,
          "note": "Dewpoint spread 2.6°C, some haze possible"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 38,
          "weight": 16,
          "note": "Milky Way core up to 11°, high enough to be worth it for 0h19m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Friday",
      "isWeekend": true
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-26",
      "score": 46,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon up all night, 46% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon up all night, 46% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 10.8,
        "hoursUseful": 0.16,
        "bestAt": "8:28pm",
        "note": "Milky Way core up to 10.8°, high enough to be worth it for 0h10m"
      },
      "window": {
        "darkFrom": "8:28pm",
        "darkTo": "5:15am",
        "hours": 8.78,
        "bestFrom": "8:28pm",
        "bestTo": "5:15am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 48,
          "weight": 32,
          "note": "46% cloud cover, 19% of it high"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 0,
          "weight": 26,
          "note": "full moon at 100%, up the whole window, washing out faint targets"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 98,
          "weight": 16,
          "note": "8h47m of astronomical darkness, 8:28pm–5:15am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 93,
          "weight": 10,
          "note": "Dewpoint spread 11.3°C, dry and steady air"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 35,
          "weight": 16,
          "note": "Milky Way core up to 10.8°, high enough to be worth it for 0h10m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Saturday",
      "isWeekend": true
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-27",
      "score": 42,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon up all night, 53% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon up all night, 53% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 10.7,
        "hoursUseful": 0.16,
        "bestAt": "8:26pm",
        "note": "Milky Way core up to 10.7°, high enough to be worth it for 0h10m"
      },
      "window": {
        "darkFrom": "8:26pm",
        "darkTo": "5:16am",
        "hours": 8.83,
        "bestFrom": "8:26pm",
        "bestTo": "5:16am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 38,
          "weight": 32,
          "note": "53% cloud cover, 28% of it high"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 0,
          "weight": 26,
          "note": "full moon at 97%, up the whole window, washing out faint targets"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 98,
          "weight": 16,
          "note": "8h50m of astronomical darkness, 8:26pm–5:16am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 88,
          "weight": 10,
          "note": "Dewpoint spread 10.8°C, dry and steady air"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 35,
          "weight": 16,
          "note": "Milky Way core up to 10.7°, high enough to be worth it for 0h10m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Sunday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-28",
      "score": 41,
      "verdict": "Poor",
      "headline": "Poor conditions. Moon up all night, 34% cloud.",
      "headlineLead": "Poor conditions",
      "headlineDetail": "moon up all night, 34% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 10.5,
        "hoursUseful": 0.16,
        "bestAt": "8:24pm",
        "note": "Milky Way core up to 10.5°, high enough to be worth it for 0h10m"
      },
      "window": {
        "darkFrom": "8:24pm",
        "darkTo": "5:18am",
        "hours": 8.89,
        "bestFrom": "8:24pm",
        "bestTo": "5:18am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 64,
          "weight": 32,
          "note": "34% cloud cover, 9% of it high"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 0,
          "weight": 26,
          "note": "waning gibbous at 92%, up the whole window, washing out faint targets"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 99,
          "weight": 16,
          "note": "8h53m of astronomical darkness, 8:24pm–5:18am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 0,
          "weight": 10,
          "note": "Dewpoint spread 1.9°C, fog or heavy haze likely"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 34,
          "weight": 16,
          "note": "Milky Way core up to 10.5°, high enough to be worth it for 0h10m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Monday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-29",
      "score": 53,
      "verdict": "Fair",
      "headline": "Workable. Moon up all night, clear skies.",
      "headlineLead": "Workable",
      "headlineDetail": "moon up all night, clear skies",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 10.3,
        "hoursUseful": 0.16,
        "bestAt": "8:22pm",
        "note": "Milky Way core up to 10.3°, high enough to be worth it for 0h10m"
      },
      "window": {
        "darkFrom": "8:22pm",
        "darkTo": "5:19am",
        "hours": 8.94,
        "bestFrom": "8:22pm",
        "bestTo": "5:19am"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 99,
          "weight": 32,
          "note": "1% cloud, essentially clear"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 0,
          "weight": 26,
          "note": "waning gibbous at 85%, up the whole window, washing out faint targets"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 99,
          "weight": 16,
          "note": "8h57m of astronomical darkness, 8:22pm–5:19am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 6,
          "weight": 10,
          "note": "Dewpoint spread 2.6°C, some haze possible"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 33,
          "weight": 16,
          "note": "Milky Way core up to 10.3°, high enough to be worth it for 0h10m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Tuesday",
      "isWeekend": false
    },
    {
      "site": "devils-tower",
      "siteName": "Devils Tower National Monument",
      "region": "Crook County, WY",
      "date": "2026-09-30",
      "score": 27,
      "verdict": "Not worth the drive",
      "headline": "Not worth the drive. Moon up after 8:30pm, 99% cloud.",
      "headlineLead": "Not worth the drive",
      "headlineDetail": "moon up after 8:30pm, 99% cloud",
      "milkyWay": {
        "visible": true,
        "maxAltitudeDeg": 10.2,
        "hoursUseful": 0.16,
        "bestAt": "8:20pm",
        "note": "Milky Way core up to 10.2°, high enough to be worth it for 0h10m"
      },
      "window": {
        "darkFrom": "8:20pm",
        "darkTo": "5:20am",
        "hours": 9,
        "bestFrom": "8:20pm",
        "bestTo": "8:30pm"
      },
      "factors": [
        {
          "key": "cloud",
          "name": "Cloud",
          "score": 0,
          "weight": 32,
          "note": "99% cloud, mostly high cirrus, thin to the eye but ruinous for photography"
        },
        {
          "key": "moon",
          "name": "Moon",
          "score": 1,
          "weight": 26,
          "note": "waning gibbous at 76%, rises 8:30pm, dark before that"
        },
        {
          "key": "darkness",
          "name": "Darkness",
          "score": 100,
          "weight": 16,
          "note": "8h60m of astronomical darkness, 8:20pm–5:20am"
        },
        {
          "key": "transparency",
          "name": "Transparency",
          "score": 57,
          "weight": 10,
          "note": "Dewpoint spread 7.7°C, some haze possible"
        },
        {
          "key": "targets",
          "name": "Targets",
          "score": 33,
          "weight": 16,
          "note": "Milky Way core up to 10.2°, high enough to be worth it for 0h10m"
        }
      ],
      "weatherBacked": true,
      "confidence": "full",
      "dataSources": {
        "astronomy": "SunCalc (local computation)",
        "weather": "Open-Meteo"
      },
      "weekday": "Wednesday",
      "isWeekend": false
    }
  ]
}