← single night · whole-night plan

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: 06-14 (25), 06-15 (20), 06-16 (16), 06-17 (13), 06-26 (11) — by astronomy; check the weather when the night is within four days.
2040-06-14astronomy score per night — click a bar for that night2040-07-13
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2040-06-14 Thu 25 — unknown 23:10–00:00 (good, 0.83 h) 50.1° 20:20 4.46 22% 44.7°
2040-06-15 Fri 20 — unknown 23:10–23:50 (good, 0.67 h) 50.1° 20:15 4.45 31% 32.7°
2040-06-16 Sat 16 — unknown 23:10–23:35 (good, 0.42 h) 50.1° 20:10 4.44 40% 20.5°
2040-06-17 Sun 13 — unknown 23:10–00:25 (marginal, 1.25 h) 50.1° 20:05 4.43 50% 8.1°
2040-06-18 Mon 10 — unknown 23:10–00:15 (marginal, 1.08 h) 50.1° 20:00 4.43 61% 4.7°
2040-06-19 Tue 8 — unknown 23:10–00:05 (marginal, 0.92 h) 50.1° 20:00 4.42 71% 17.8°
2040-06-20 Wed 6 — unknown 23:15–23:50 (marginal, 0.58 h) 50.1° 19:55 4.42 80% 31.5°
2040-06-21 Thu 6 — unknown 23:15–23:50 (marginal, 0.58 h) 50.1° 19:50 4.42 88% 45.6°
2040-06-22 Fri 6 — unknown 23:15–23:50 (marginal, 0.58 h) 50.1° 19:45 4.43 95% 60.1°
2040-06-23 Sat 7 — unknown 23:15–23:55 (marginal, 0.67 h) 50.1° 19:40 4.43 99% 75.0°
2040-06-24 Sun 9 — unknown 23:15–00:00 (marginal, 0.75 h) 50.1° 19:40 4.44 100% 90.2°
2040-06-25 Mon 10 — unknown 23:15–23:55 (marginal, 0.67 h) 50.1° 19:35 4.45 98% 105.4°
2040-06-26 Tue 11 — unknown 22:20–23:50 (marginal, 1.5 h) 50.1° 19:30 4.46 93% 120.5°
2040-06-27 Wed 11 — unknown 23:15–23:20 (good, 0.08 h) 50.1° 19:25 4.48 86% 135.4°
2040-06-28 Thu 11 — unknown 23:10–23:15 (good, 0.08 h) 50.1° 19:25 4.49 76% 149.9°
2040-06-29 Fri 10 — unknown 22:20–23:40 (marginal, 1.33 h) 50.1° 19:20 4.51 66% 164.0°
2040-06-30 Sat 8 — unknown 22:20–23:05 (marginal, 0.75 h) 50.1° 19:15 4.53 55% 177.7°
2040-07-01 Sun 7 — unknown 22:20–23:05 (marginal, 0.75 h) 50.1° 19:10 4.55 45% 169.0°
2040-07-02 Mon 6 — unknown 22:20–23:00 (marginal, 0.67 h) 50.1° 19:05 4.57 34% 156.1°
2040-07-03 Tue 6 — unknown 22:20–22:55 (marginal, 0.58 h) 50.1° 19:05 4.6 25% 143.5°
2040-07-04 Wed 5 — unknown 22:20–22:50 (marginal, 0.5 h) 50.1° 19:00 4.63 17% 131.2°
2040-07-05 Thu 4 — unknown 22:20–22:45 (marginal, 0.42 h) 50.1° 18:55 4.66 10% 119.0°
2040-07-06 Fri 3 — unknown 22:15–22:45 (marginal, 0.5 h) 50.1° 18:50 4.69 5% 107.0°
2040-07-07 Sat 3 — unknown 22:15–22:40 (marginal, 0.42 h) 50.1° 18:45 4.72 2% 95.0°
2040-07-08 Sun 3 — unknown 22:15–22:35 (marginal, 0.33 h) 50.1° 18:45 4.75 0% 83.2°
2040-07-09 Mon 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.1° 18:40 4.79 0% 71.4°
2040-07-10 Tue 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.1° 18:35 4.82 2% 59.5°
2040-07-11 Wed 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.1° 18:30 4.86 6% 47.7°
2040-07-12 Thu 2 — unknown — 50.1° 18:30 4.9 11% 35.7°
2040-07-13 Fri 1 — unknown — 50.1° 18:25 4.94 18% 23.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-06-14&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.