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: 11-10 (89), 11-11 (89), 11-12 (89), 11-13 (89), 11-14 (89) — by astronomy; check the weather when the night is within four days.

2045-11-10astronomy score per night — click a bar for that night2045-12-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-11-10 Fri	89	—	unknown	23:20–05:30 (good, 6.17 h)	42.9° 02:35	10.82	5%	145.8°
2045-11-11 Sat	89	—	unknown	23:20–05:35 (good, 6.25 h)	42.9° 02:30	10.85	10%	147.2°
2045-11-12 Sun	89	—	unknown	23:15–05:35 (good, 6.33 h)	42.9° 02:30	10.88	17%	144.4°
2045-11-13 Mon	89	—	unknown	23:10–05:35 (good, 6.42 h)	42.9° 02:25	10.91	25%	138.4°
2045-11-14 Tue	89	—	unknown	23:05–05:35 (good, 6.5 h)	42.9° 02:20	10.94	34%	130.5°
2045-11-15 Wed	89	—	unknown	23:00–05:35 (good, 6.58 h)	42.9° 02:15	10.97	43%	121.7°
2045-11-16 Thu	89	—	unknown	23:05–05:30 (good, 6.42 h)	42.9° 02:15	11.0	53%	112.3°
2045-11-17 Fri	89	—	unknown	23:05–05:30 (good, 6.42 h)	42.9° 02:10	11.03	62%	102.5°
2045-11-18 Sat	89	—	unknown	23:15–05:25 (good, 6.17 h)	42.9° 02:05	11.05	71%	92.5°
2045-11-19 Sun	88	—	unknown	23:35–05:20 (good, 5.75 h)	42.9° 02:00	11.08	79%	82.4°
2045-11-20 Mon	84	—	unknown	01:20–05:15 (good, 3.92 h)	42.9° 01:55	11.1	86%	72.1°
2045-11-21 Tue	58	—	unknown	05:05–05:10 (good, 0.08 h)	42.9° 01:55	11.13	93%	61.9°
2045-11-22 Wed	35	—	unknown	23:00–05:30 (marginal, 6.5 h)	42.9° 01:50	11.15	97%	52.1°
2045-11-23 Thu	22	—	unknown	01:20–05:05 (marginal, 3.75 h)	42.9° 01:45	11.18	99%	43.1°
2045-11-24 Fri	14	—	unknown	—	42.9° 01:40	11.2	100%	36.1°
2045-11-25 Sat	11	—	unknown	—	42.9° 01:35	11.22	97%	32.8°
2045-11-26 Sun	16	—	unknown	22:45–23:50 (marginal, 1.08 h)	42.9° 01:35	11.24	93%	34.4°
2045-11-27 Mon	28	—	unknown	22:05–04:25 (marginal, 6.33 h)	42.9° 01:30	11.26	86%	40.5°
2045-11-28 Tue	46	—	unknown	21:45–04:45 (marginal, 7.0 h)	42.9° 01:25	11.28	77%	49.6°
2045-11-29 Wed	64	—	unknown	22:35–02:00 (good, 3.42 h)	42.9° 01:20	11.3	67%	60.2°
2045-11-30 Thu	84	—	unknown	22:05–04:05 (good, 6.0 h)	42.9° 01:20	11.32	56%	71.6°
2045-12-01 Fri	88	—	unknown	22:00–04:15 (good, 6.25 h)	42.9° 01:15	11.34	44%	83.4°
2045-12-02 Sat	89	—	unknown	21:55–04:20 (good, 6.42 h)	42.9° 01:10	11.35	33%	95.2°
2045-12-03 Sun	89	—	unknown	21:50–04:20 (good, 6.5 h)	42.9° 01:05	11.37	23%	106.8°
2045-12-04 Mon	89	—	unknown	21:50–04:20 (good, 6.5 h)	42.9° 01:00	11.39	14%	118.0°
2045-12-05 Tue	89	—	unknown	21:45–04:15 (good, 6.5 h)	42.9° 01:00	11.4	8%	128.5°
2045-12-06 Wed	89	—	unknown	21:40–04:15 (good, 6.58 h)	42.9° 00:55	11.41	3%	137.5°
2045-12-07 Thu	89	—	unknown	21:35–04:10 (good, 6.58 h)	42.9° 00:50	11.43	0%	144.2°
2045-12-08 Fri	89	—	unknown	21:30–04:05 (good, 6.58 h)	42.9° 00:45	11.44	0%	147.3°
2045-12-09 Sat	89	—	unknown	21:30–04:00 (good, 6.5 h)	42.9° 00:40	11.45	2%	146.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-11-10&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.