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: 11-18 (89), 11-19 (89), 11-20 (89), 11-21 (89), 11-22 (89) — by astronomy; check the weather when the night is within four days.

2047-11-18astronomy score per night — click a bar for that night2047-12-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-11-18 Mon	89	—	unknown	22:55–05:25 (good, 6.5 h)	42.9° 02:05	11.04	3%	148.7°
2047-11-19 Tue	89	—	unknown	22:50–05:20 (good, 6.5 h)	42.9° 02:05	11.07	8%	149.7°
2047-11-20 Wed	89	—	unknown	22:45–05:20 (good, 6.58 h)	42.9° 02:00	11.09	16%	144.7°
2047-11-21 Thu	89	—	unknown	22:40–05:15 (good, 6.58 h)	42.9° 01:55	11.12	25%	136.1°
2047-11-22 Fri	89	—	unknown	22:35–05:10 (good, 6.58 h)	42.9° 01:50	11.14	35%	125.9°
2047-11-23 Sat	89	—	unknown	22:40–05:05 (good, 6.42 h)	42.9° 01:45	11.17	46%	115.2°
2047-11-24 Sun	89	—	unknown	22:40–05:00 (good, 6.33 h)	42.9° 01:45	11.19	56%	104.4°
2047-11-25 Mon	89	—	unknown	22:45–05:00 (good, 6.25 h)	42.9° 01:40	11.21	65%	93.6°
2047-11-26 Tue	88	—	unknown	22:55–04:55 (good, 6.0 h)	42.9° 01:35	11.23	74%	83.1°
2047-11-27 Wed	84	—	unknown	00:30–04:50 (good, 4.33 h)	42.9° 01:30	11.25	82%	72.7°
2047-11-28 Thu	66	—	unknown	04:30–04:45 (good, 0.25 h)	42.9° 01:30	11.27	89%	62.7°
2047-11-29 Fri	39	—	unknown	22:25–05:10 (marginal, 6.75 h)	42.9° 01:25	11.29	94%	53.1°
2047-11-30 Sat	25	—	unknown	00:00–04:50 (marginal, 4.83 h)	42.9° 01:20	11.31	98%	44.3°
2047-12-01 Sun	16	—	unknown	02:55–04:20 (marginal, 1.42 h)	42.9° 01:15	11.33	100%	36.7°
2047-12-02 Mon	10	—	unknown	—	42.9° 01:10	11.35	100%	31.5°
2047-12-03 Tue	10	—	unknown	—	42.9° 01:10	11.36	98%	29.8°
2047-12-04 Wed	15	—	unknown	22:15–23:00 (marginal, 0.75 h)	42.9° 01:05	11.38	95%	32.4°
2047-12-05 Thu	25	—	unknown	21:35–03:15 (marginal, 5.67 h)	42.9° 01:00	11.39	90%	38.5°
2047-12-06 Fri	41	—	unknown	21:15–04:10 (marginal, 6.92 h)	42.9° 00:55	11.41	83%	46.9°
2047-12-07 Sat	60	—	unknown	22:10–23:30 (good, 1.33 h)	42.9° 00:50	11.42	74%	56.6°
2047-12-08 Sun	83	—	unknown	21:35–02:45 (good, 5.17 h)	42.9° 00:50	11.43	65%	67.2°
2047-12-09 Mon	87	—	unknown	21:30–03:40 (good, 6.17 h)	42.9° 00:45	11.44	55%	78.4°
2047-12-10 Tue	89	—	unknown	21:25–03:45 (good, 6.33 h)	42.9° 00:40	11.45	44%	90.1°
2047-12-11 Wed	89	—	unknown	21:20–03:50 (good, 6.5 h)	42.9° 00:35	11.46	33%	102.2°
2047-12-12 Thu	89	—	unknown	21:20–03:50 (good, 6.5 h)	42.9° 00:30	11.47	22%	114.3°
2047-12-13 Fri	89	—	unknown	21:15–03:50 (good, 6.58 h)	42.9° 00:30	11.48	14%	126.3°
2047-12-14 Sat	89	—	unknown	21:10–03:45 (good, 6.58 h)	42.9° 00:25	11.48	6%	137.3°
2047-12-15 Sun	89	—	unknown	21:05–03:40 (good, 6.58 h)	42.9° 00:20	11.49	2%	146.1°
2047-12-16 Mon	89	—	unknown	21:05–03:35 (good, 6.5 h)	42.9° 00:15	11.5	0%	150.1°
2047-12-17 Tue	89	—	unknown	21:00–03:30 (good, 6.5 h)	42.9° 00:15	11.5	1%	147.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-11-18&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.