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 HD 189733: 04-01 (46), 04-02 (46), 04-04 (46), 03-30 (45), 03-31 (45) — by astronomy; check the weather when the night is within four days.

2031-03-11astronomy score per night — click a bar for that night2031-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-03-11 Tue	19	—	unknown	04:25–05:10 (good, 0.75 h)	71.1° 09:05	9.18	91%	102.0°
2031-03-12 Wed	18	—	unknown	04:25–05:05 (good, 0.67 h)	71.1° 09:00	9.14	84%	91.1°
2031-03-13 Thu	18	—	unknown	04:20–05:05 (good, 0.75 h)	71.1° 08:55	9.09	75%	80.1°
2031-03-14 Fri	18	—	unknown	04:15–05:05 (good, 0.83 h)	71.1° 08:50	9.04	65%	69.3°
2031-03-15 Sat	19	—	unknown	04:10–05:00 (good, 0.83 h)	71.1° 08:50	8.99	54%	59.0°
2031-03-16 Sun	22	—	unknown	04:00–05:00 (good, 1.0 h)	71.1° 08:45	8.94	42%	49.6°
2031-03-17 Mon	26	—	unknown	03:50–05:00 (good, 1.17 h)	71.1° 08:40	8.89	31%	42.2°
2031-03-18 Tue	29	—	unknown	03:35–04:55 (good, 1.33 h)	71.1° 08:35	8.84	21%	38.0°
2031-03-19 Wed	34	—	unknown	03:30–04:55 (good, 1.42 h)	71.1° 08:35	8.78	13%	38.0°
2031-03-20 Thu	37	—	unknown	03:30–04:55 (good, 1.42 h)	71.1° 08:30	8.73	6%	42.3°
2031-03-21 Fri	37	—	unknown	03:25–04:50 (good, 1.42 h)	71.1° 08:25	8.68	2%	49.6°
2031-03-22 Sat	38	—	unknown	03:20–04:50 (good, 1.5 h)	71.1° 08:20	8.63	0%	58.6°
2031-03-23 Sun	38	—	unknown	03:15–04:45 (good, 1.5 h)	71.1° 08:15	8.58	1%	68.4°
2031-03-24 Mon	40	—	unknown	03:10–04:45 (good, 1.58 h)	71.1° 08:15	8.52	4%	78.6°
2031-03-25 Tue	41	—	unknown	03:10–04:45 (good, 1.58 h)	71.1° 08:10	8.47	8%	88.7°
2031-03-26 Wed	41	—	unknown	03:05–04:40 (good, 1.58 h)	71.1° 08:05	8.42	15%	98.7°
2031-03-27 Thu	42	—	unknown	03:00–04:40 (good, 1.67 h)	71.1° 08:00	8.36	22%	108.2°
2031-03-28 Fri	43	—	unknown	02:55–04:40 (good, 1.75 h)	71.1° 07:55	8.31	31%	117.3°
2031-03-29 Sat	44	—	unknown	02:50–05:35 (good, 1.75 h)	71.1° 08:55	8.26	40%	125.6°
2031-03-30 Sun	45	—	unknown	03:50–05:35 (good, 1.75 h)	71.1° 08:50	8.2	49%	132.9°
2031-03-31 Mon	45	—	unknown	03:45–05:30 (good, 1.75 h)	71.1° 08:45	8.15	59%	138.7°
2031-04-01 Tue	46	—	unknown	03:45–05:30 (good, 1.75 h)	71.1° 08:40	8.09	68%	142.1°
2031-04-02 Wed	46	—	unknown	03:40–05:30 (good, 1.83 h)	71.1° 08:40	8.04	76%	142.4°
2031-04-03 Thu	45	—	unknown	03:40–05:25 (good, 1.75 h)	71.1° 08:35	7.98	84%	139.4°
2031-04-04 Fri	46	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:30	7.93	91%	133.5°
2031-04-05 Sat	41	—	unknown	03:35–05:20 (good, 1.75 h)	71.1° 08:25	7.87	96%	125.4°
2031-04-06 Sun	39	—	unknown	03:35–05:20 (good, 1.75 h)	71.1° 08:20	7.82	99%	116.0°
2031-04-07 Mon	35	—	unknown	03:35–05:20 (good, 1.75 h)	71.1° 08:20	7.76	100%	105.5°
2031-04-08 Tue	31	—	unknown	03:40–05:15 (good, 1.58 h)	71.1° 08:15	7.7	98%	94.5°
2031-04-09 Wed	28	—	unknown	04:10–05:15 (good, 1.08 h)	71.1° 08:10	7.65	94%	83.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-03-11&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.