← 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: 06-23 (16), 06-24 (15), 06-25 (13), 06-26 (10), 06-27 (8) — by astronomy; check the weather when the night is within four days.
2028-06-23astronomy score per night — click a bar for that night2028-07-22
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2028-06-23 Fri 16 — unknown 23:15–23:35 (good, 0.33 h) 50.2° 19:40 4.43 2% 77.6°
2028-06-24 Sat 15 — unknown 23:15–23:30 (good, 0.25 h) 50.2° 19:40 4.44 6% 63.5°
2028-06-25 Sun 13 — unknown 23:15–23:25 (good, 0.17 h) 50.2° 19:35 4.45 13% 49.3°
2028-06-26 Mon 10 — unknown 22:20–23:50 (marginal, 1.5 h) 50.2° 19:30 4.46 22% 35.3°
2028-06-27 Tue 8 — unknown 22:20–23:05 (marginal, 0.75 h) 50.2° 19:25 4.47 32% 21.9°
2028-06-28 Wed 7 — unknown 23:10–23:45 (marginal, 0.58 h) 50.2° 19:20 4.49 43% 11.2°
2028-06-29 Thu 5 — unknown 23:10–23:40 (marginal, 0.5 h) 50.2° 19:20 4.51 55% 13.0°
2028-06-30 Fri 3 — unknown 23:10–23:25 (marginal, 0.25 h) 50.2° 19:15 4.53 66% 24.5°
2028-07-01 Sat 3 — unknown 23:10–23:20 (marginal, 0.17 h) 50.2° 19:10 4.55 76% 37.4°
2028-07-02 Sun 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.2° 19:05 4.57 85% 50.5°
2028-07-03 Mon 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.2° 19:05 4.6 92% 63.5°
2028-07-04 Tue 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.2° 19:00 4.62 96% 76.4°
2028-07-05 Wed 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.2° 18:55 4.65 99% 89.1°
2028-07-06 Thu 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.2° 18:50 4.68 100% 101.5°
2028-07-07 Fri 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.2° 18:45 4.71 99% 113.8°
2028-07-08 Sat 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.2° 18:45 4.75 95% 125.8°
2028-07-09 Sun 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.2° 18:40 4.78 90% 137.5°
2028-07-10 Mon 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.2° 18:35 4.82 84% 149.0°
2028-07-11 Tue 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.2° 18:30 4.86 77% 159.8°
2028-07-12 Wed 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.2° 18:25 4.9 68% 168.6°
2028-07-13 Thu 2 — unknown — 50.2° 18:25 4.94 59% 168.5°
2028-07-14 Fri 1 — unknown — 50.2° 18:20 4.98 49% 159.6°
2028-07-15 Sat 1 — unknown — 50.2° 18:15 5.02 40% 148.3°
2028-07-16 Sun 1 — unknown — 50.2° 18:10 5.06 30% 136.3°
2028-07-17 Mon 1 — unknown — 50.2° 18:10 5.11 21% 123.8°
2028-07-18 Tue 1 — unknown — 50.2° 18:05 5.15 13% 110.7°
2028-07-19 Wed 1 — unknown — 50.2° 18:00 5.2 6% 97.2°
2028-07-20 Thu 1 — unknown — 50.2° 17:55 5.25 2% 83.2°
2028-07-21 Fri 0 — unknown — 50.2° 17:50 5.3 0% 68.9°
2028-07-22 Sat 0 — unknown — 50.2° 17:50 5.35 1% 54.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-06-23&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.