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 Great Orion Nebula: 11-16 (89), 11-17 (89), 11-18 (89), 11-19 (89), 11-20 (89) — by astronomy; check the weather when the night is within four days.

2028-11-16astronomy score per night — click a bar for that night2028-12-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-11-16 Thu	89	—	unknown	22:55–05:30 (good, 6.58 h)	42.9° 02:10	11.0	0%	140.9°
2028-11-17 Fri	89	—	unknown	22:55–05:25 (good, 6.5 h)	42.9° 02:05	11.03	2%	147.6°
2028-11-18 Sat	89	—	unknown	22:50–05:25 (good, 6.58 h)	42.9° 02:05	11.06	7%	149.4°
2028-11-19 Sun	89	—	unknown	22:45–05:20 (good, 6.58 h)	42.9° 02:00	11.08	14%	146.1°
2028-11-20 Mon	89	—	unknown	22:40–05:15 (good, 6.58 h)	42.9° 01:55	11.11	21%	139.2°
2028-11-21 Tue	89	—	unknown	22:40–05:10 (good, 6.5 h)	42.9° 01:50	11.13	30%	130.4°
2028-11-22 Wed	89	—	unknown	22:35–05:05 (good, 6.5 h)	42.9° 01:50	11.16	40%	120.8°
2028-11-23 Thu	89	—	unknown	22:35–05:05 (good, 6.5 h)	42.9° 01:45	11.18	49%	110.9°
2028-11-24 Fri	89	—	unknown	22:40–05:00 (good, 6.33 h)	42.9° 01:40	11.2	59%	100.8°
2028-11-25 Sat	89	—	unknown	22:45–04:55 (good, 6.17 h)	42.9° 01:35	11.22	68%	90.6°
2028-11-26 Sun	87	—	unknown	23:15–04:50 (good, 5.58 h)	42.9° 01:30	11.25	76%	80.4°
2028-11-27 Mon	82	—	unknown	01:00–04:45 (good, 3.75 h)	42.9° 01:30	11.27	84%	70.3°
2028-11-28 Tue	52	—	unknown	22:10–05:15 (marginal, 7.08 h)	42.9° 01:25	11.29	90%	60.3°
2028-11-29 Wed	34	—	unknown	22:30–05:00 (marginal, 6.5 h)	42.9° 01:20	11.3	95%	50.6°
2028-11-30 Thu	21	—	unknown	01:00–04:40 (marginal, 3.67 h)	42.9° 01:15	11.32	98%	41.8°
2028-12-01 Fri	13	—	unknown	—	42.9° 01:10	11.34	100%	34.6°
2028-12-02 Sat	9	—	unknown	—	42.9° 01:10	11.36	99%	30.7°
2028-12-03 Sun	13	—	unknown	—	42.9° 01:05	11.37	96%	31.6°
2028-12-04 Mon	22	—	unknown	21:45–02:05 (marginal, 4.33 h)	42.9° 01:00	11.39	91%	37.1°
2028-12-05 Tue	38	—	unknown	21:20–04:05 (marginal, 6.75 h)	42.9° 00:55	11.4	84%	45.7°
2028-12-06 Wed	58	—	unknown	21:10–04:25 (marginal, 7.25 h)	42.9° 00:55	11.41	75%	56.1°
2028-12-07 Thu	83	—	unknown	21:35–02:45 (good, 5.17 h)	42.9° 00:50	11.43	65%	67.5°
2028-12-08 Fri	88	—	unknown	21:30–03:40 (good, 6.17 h)	42.9° 00:45	11.44	54%	79.4°
2028-12-09 Sat	89	—	unknown	21:25–03:50 (good, 6.42 h)	42.9° 00:40	11.45	42%	91.5°
2028-12-10 Sun	89	—	unknown	21:25–03:50 (good, 6.42 h)	42.9° 00:35	11.46	31%	103.7°
2028-12-11 Mon	89	—	unknown	21:20–03:50 (good, 6.5 h)	42.9° 00:35	11.47	21%	115.7°
2028-12-12 Tue	89	—	unknown	21:15–03:50 (good, 6.58 h)	42.9° 00:30	11.48	12%	127.2°
2028-12-13 Wed	89	—	unknown	21:10–03:45 (good, 6.58 h)	42.9° 00:25	11.48	6%	137.4°
2028-12-14 Thu	89	—	unknown	21:05–03:40 (good, 6.58 h)	42.9° 00:20	11.49	2%	145.4°
2028-12-15 Fri	89	—	unknown	21:05–03:35 (good, 6.5 h)	42.9° 00:15	11.49	0%	149.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-11-16&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.