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Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Triangulum Pinwheel: 01-21 (100), 01-22 (93), 01-23 (83), 02-04 (81), 02-03 (80) — by astronomy; check the weather when the night is within four days.
2026-01-21astronomy score per night — click a bar for that night2026-02-19
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-01-21 Wed 100 0 0 — 79.1° 17:50 11.08 10% 57.0°
2026-01-22 Thu 93 0 0 — 79.1° 17:50 11.06 17% 44.6°
2026-01-23 Fri 83 53 44 19:05–21:00 (good, 1.92 h) 79.1° 17:45 11.03 26% 32.4°
2026-01-24 Sat 65 9 6 — 79.1° 17:40 11.0 36% 21.4°
2026-01-25 Sun 49 0 0 — 79.1° 17:35 10.97 47% 15.2°
2026-01-26 Mon 34 0 0 — 79.1° 17:35 10.94 58% 19.6°
2026-01-27 Tue 22 16 4 — 79.1° 17:30 10.91 69% 30.5°
2026-01-28 Wed 21 0 0 — 79.1° 17:25 10.88 80% 43.5°
2026-01-29 Thu 24 0 0 — 79.1° 17:20 10.85 88% 57.1°
2026-01-30 Fri 31 0 0 — 79.1° 17:15 10.82 95% 71.0°
2026-01-31 Sat 41 0 0 — 79.1° 17:15 10.79 99% 84.9°
2026-02-01 Sun 54 0 0 — 79.1° 17:10 10.76 100% 98.7°
2026-02-02 Mon 66 0 0 — 79.1° 17:05 10.72 99% 112.2°
2026-02-03 Tue 80 10 8 18:45–19:00 (marginal, 0.25 h) 79.1° 17:00 10.69 95% 125.2°
2026-02-04 Wed 81 0 0 — 79.1° 16:55 10.66 89% 137.7°
2026-02-05 Thu 80 0 0 — 79.1° 16:55 10.62 82% 149.2°
2026-02-06 Fri 79 0 0 — 79.1° 16:50 10.59 74% 159.1°
2026-02-07 Sat 76 90 69 19:20–22:10 (good, 2.83 h) 79.1° 16:45 10.55 65% 164.7°
2026-02-08 Sun 74 38 28 19:20–20:00 (good, 0.67 h) 79.1° 16:40 10.51 56% 162.1°
2026-02-09 Mon 71 0 0 — 79.1° 16:40 10.48 46% 153.9°
2026-02-10 Tue 69 0 0 — 79.1° 16:35 10.44 37% 143.8°
2026-02-11 Wed 66 0 0 — 79.1° 16:30 10.4 28% 132.9°
2026-02-12 Thu 64 0 0 — 79.1° 16:25 10.36 20% 121.6°
2026-02-13 Fri 62 0 0 — 79.1° 16:20 10.32 13% 110.0°
2026-02-14 Sat 60 2 1 — 79.1° 16:20 10.29 7% 98.0°
2026-02-15 Sun 57 0 0 — 79.1° 16:15 10.25 3% 85.8°
2026-02-16 Mon 55 21 12 19:30–19:40 (good, 0.17 h) 79.1° 16:10 10.21 0% 73.4°
2026-02-17 Tue 53 0 0 — 79.1° 16:05 10.17 0% 60.7°
2026-02-18 Wed 51 96 49 19:35–21:25 (good, 1.83 h) 79.1° 16:00 10.12 2% 48.0°
2026-02-19 Thu 47 0 0 — 79.1° 16:00 10.08 7% 35.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-01-21&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.