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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 3C 273: 06-22 (18), 06-23 (16), 06-24 (15), 06-25 (14), 06-26 (12) — by astronomy; check the weather when the night is within four days.
2036-06-22astronomy score per night — click a bar for that night2036-07-21
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2036-06-22 Sun 18 — unknown 23:15–23:40 (good, 0.42 h) 50.2° 19:45 4.43 2% 110.7°
2036-06-23 Mon 16 — unknown 23:15–23:35 (good, 0.33 h) 50.2° 19:40 4.43 0% 95.9°
2036-06-24 Tue 15 — unknown 23:15–23:30 (good, 0.25 h) 50.2° 19:40 4.44 1% 81.0°
2036-06-25 Wed 14 — unknown 23:15–23:25 (good, 0.17 h) 50.2° 19:35 4.45 5% 65.9°
2036-06-26 Thu 12 — unknown 23:15–23:20 (good, 0.08 h) 50.2° 19:30 4.46 11% 51.0°
2036-06-27 Fri 9 — unknown 22:20–23:10 (marginal, 0.83 h) 50.2° 19:25 4.48 20% 36.2°
2036-06-28 Sat 8 — unknown 23:10–23:45 (marginal, 0.58 h) 50.2° 19:25 4.49 30% 21.8°
2036-06-29 Sun 6 — unknown 23:10–23:40 (marginal, 0.5 h) 50.2° 19:20 4.51 41% 7.8°
2036-06-30 Mon 4 — unknown 23:10–23:30 (marginal, 0.33 h) 50.2° 19:15 4.53 52% 6.0°
2036-07-01 Tue 3 — unknown 23:10–23:20 (marginal, 0.17 h) 50.2° 19:10 4.55 63% 19.3°
2036-07-02 Wed 2 — unknown — 50.2° 19:05 4.57 72% 32.4°
2036-07-03 Thu 2 — unknown — 50.2° 19:05 4.6 81% 45.1°
2036-07-04 Fri 2 — unknown — 50.2° 19:00 4.63 88% 57.7°
2036-07-05 Sat 2 — unknown — 50.2° 18:55 4.65 94% 70.1°
2036-07-06 Sun 2 — unknown — 50.2° 18:50 4.69 98% 82.3°
2036-07-07 Mon 2 — unknown — 50.2° 18:45 4.72 100% 94.3°
2036-07-08 Tue 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.2° 18:45 4.75 100% 106.3°
2036-07-09 Wed 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.2° 18:40 4.79 98% 118.1°
2036-07-10 Thu 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.2° 18:35 4.82 95% 130.0°
2036-07-11 Fri 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.2° 18:30 4.86 90% 141.8°
2036-07-12 Sat 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.2° 18:30 4.9 83% 153.7°
2036-07-13 Sun 2 — unknown — 50.2° 18:25 4.94 75% 165.7°
2036-07-14 Mon 1 — unknown — 50.2° 18:20 4.98 66% 177.7°
2036-07-15 Tue 1 — unknown — 50.2° 18:15 5.02 57% 169.8°
2036-07-16 Wed 1 — unknown — 50.2° 18:10 5.07 47% 157.1°
2036-07-17 Thu 1 — unknown — 50.2° 18:10 5.11 36% 144.1°
2036-07-18 Fri 1 — unknown — 50.2° 18:05 5.16 26% 130.7°
2036-07-19 Sat 1 — unknown — 50.2° 18:00 5.2 17% 116.7°
2036-07-20 Sun 1 — unknown — 50.2° 17:55 5.25 9% 102.3°
2036-07-21 Mon 0 — unknown — 50.2° 17:50 5.3 3% 87.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-06-22&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.