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 North America Nebula: 04-02 (52), 03-30 (51), 04-01 (51), 04-03 (51), 04-04 (51) — by astronomy; check the weather when the night is within four days.

2031-03-09astronomy score per night — click a bar for that night2031-04-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-03-09 Sun	26	—	unknown	04:10–05:10 (good, 1.0 h)	87.2° 10:10	9.28	99%	124.9°
2031-03-10 Mon	27	—	unknown	04:05–05:10 (good, 1.08 h)	87.2° 10:05	9.23	96%	120.6°
2031-03-11 Tue	27	—	unknown	04:05–05:10 (good, 1.08 h)	87.2° 10:00	9.18	91%	114.7°
2031-03-12 Wed	25	—	unknown	04:00–05:05 (good, 1.08 h)	87.2° 10:00	9.14	84%	107.5°
2031-03-13 Thu	25	—	unknown	04:00–05:05 (good, 1.08 h)	87.2° 09:55	9.09	75%	99.5°
2031-03-14 Fri	26	—	unknown	03:55–05:05 (good, 1.17 h)	87.2° 09:50	9.04	65%	91.0°
2031-03-15 Sat	27	—	unknown	03:50–05:00 (good, 1.17 h)	87.2° 09:45	8.99	54%	82.5°
2031-03-16 Sun	30	—	unknown	03:40–05:00 (good, 1.33 h)	87.2° 09:40	8.94	42%	74.2°
2031-03-17 Mon	33	—	unknown	03:35–05:00 (good, 1.42 h)	87.2° 09:40	8.89	31%	66.6°
2031-03-18 Tue	36	—	unknown	03:20–04:55 (good, 1.58 h)	87.2° 09:35	8.84	21%	60.1°
2031-03-19 Wed	41	—	unknown	03:15–04:55 (good, 1.67 h)	87.2° 09:30	8.78	13%	55.3°
2031-03-20 Thu	43	—	unknown	03:10–04:55 (good, 1.75 h)	87.2° 09:25	8.73	6%	52.8°
2031-03-21 Fri	43	—	unknown	03:05–04:50 (good, 1.75 h)	87.2° 09:25	8.68	2%	52.8°
2031-03-22 Sat	44	—	unknown	03:05–04:50 (good, 1.75 h)	87.2° 09:20	8.63	0%	55.3°
2031-03-23 Sun	44	—	unknown	03:00–04:45 (good, 1.75 h)	87.2° 09:15	8.58	1%	59.8°
2031-03-24 Mon	46	—	unknown	02:55–04:45 (good, 1.83 h)	87.2° 09:10	8.52	4%	65.7°
2031-03-25 Tue	47	—	unknown	02:50–04:45 (good, 1.92 h)	87.2° 09:05	8.47	8%	72.5°
2031-03-26 Wed	47	—	unknown	02:50–04:40 (good, 1.83 h)	87.2° 09:05	8.42	15%	79.7°
2031-03-27 Thu	48	—	unknown	02:45–04:40 (good, 1.92 h)	87.2° 09:00	8.36	22%	87.0°
2031-03-28 Fri	49	—	unknown	02:40–04:40 (good, 2.0 h)	87.2° 08:55	8.31	31%	94.4°
2031-03-29 Sat	50	—	unknown	02:35–05:35 (good, 2.0 h)	87.2° 09:50	8.26	40%	101.5°
2031-03-30 Sun	51	—	unknown	03:30–05:35 (good, 2.08 h)	87.2° 09:45	8.2	49%	108.3°
2031-03-31 Mon	50	—	unknown	03:30–05:30 (good, 2.0 h)	87.2° 09:45	8.15	59%	114.5°
2031-04-01 Tue	51	—	unknown	03:30–05:30 (good, 2.0 h)	87.2° 09:40	8.09	68%	119.9°
2031-04-02 Wed	52	—	unknown	03:30–05:30 (good, 2.0 h)	87.2° 09:35	8.04	76%	124.1°
2031-04-03 Thu	51	—	unknown	03:25–05:25 (good, 2.0 h)	87.2° 09:30	7.98	84%	126.8°
2031-04-04 Fri	51	—	unknown	03:25–05:25 (good, 2.0 h)	87.2° 09:25	7.93	91%	127.5°
2031-04-05 Sat	45	—	unknown	03:20–05:20 (good, 2.0 h)	87.2° 09:25	7.87	96%	126.0°
2031-04-06 Sun	46	—	unknown	03:20–05:20 (good, 2.0 h)	87.2° 09:20	7.82	99%	122.4°
2031-04-07 Mon	45	—	unknown	03:15–05:20 (good, 2.08 h)	87.2° 09:15	7.76	100%	116.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-03-09&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.