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: 11-20 (89), 11-21 (89), 11-22 (89), 11-23 (89), 11-24 (89) — by astronomy; check the weather when the night is within four days.

2030-11-16astronomy score per night — click a bar for that night2030-12-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-11-16 Sat	59	—	unknown	23:55–00:50 (good, 0.92 h)	42.9° 02:15	10.99	64%	49.2°
2030-11-17 Sun	79	—	unknown	22:55–04:15 (good, 5.33 h)	42.9° 02:10	11.02	54%	59.3°
2030-11-18 Mon	85	—	unknown	22:50–05:00 (good, 6.17 h)	42.9° 02:05	11.04	44%	70.1°
2030-11-19 Tue	88	—	unknown	22:45–05:10 (good, 6.42 h)	42.9° 02:00	11.07	34%	81.5°
2030-11-20 Wed	89	—	unknown	22:45–05:10 (good, 6.42 h)	42.9° 02:00	11.1	24%	93.4°
2030-11-21 Thu	89	—	unknown	22:40–05:10 (good, 6.5 h)	42.9° 01:55	11.12	16%	105.7°
2030-11-22 Fri	89	—	unknown	22:35–05:10 (good, 6.58 h)	42.9° 01:50	11.14	8%	118.2°
2030-11-23 Sat	89	—	unknown	22:30–05:05 (good, 6.58 h)	42.9° 01:45	11.17	3%	130.4°
2030-11-24 Sun	89	—	unknown	22:30–05:00 (good, 6.5 h)	42.9° 01:40	11.19	0%	141.7°
2030-11-25 Mon	89	—	unknown	22:25–04:55 (good, 6.5 h)	42.9° 01:40	11.21	1%	150.1°
2030-11-26 Tue	89	—	unknown	22:20–04:55 (good, 6.58 h)	42.9° 01:35	11.24	4%	152.8°
2030-11-27 Wed	89	—	unknown	22:15–04:50 (good, 6.58 h)	42.9° 01:30	11.26	10%	148.2°
2030-11-28 Thu	89	—	unknown	22:10–04:45 (good, 6.58 h)	42.9° 01:25	11.28	18%	139.0°
2030-11-29 Fri	89	—	unknown	22:10–04:40 (good, 6.5 h)	42.9° 01:20	11.3	28%	127.9°
2030-11-30 Sat	89	—	unknown	22:10–04:40 (good, 6.5 h)	42.9° 01:20	11.31	39%	116.2°
2030-12-01 Sun	89	—	unknown	22:10–04:35 (good, 6.42 h)	42.9° 01:15	11.33	50%	104.5°
2030-12-02 Mon	89	—	unknown	22:15–04:30 (good, 6.25 h)	42.9° 01:10	11.35	60%	92.9°
2030-12-03 Tue	87	—	unknown	22:25–04:25 (good, 6.0 h)	42.9° 01:05	11.36	70%	81.6°
2030-12-04 Wed	83	—	unknown	00:00–04:20 (good, 4.33 h)	42.9° 01:05	11.38	78%	70.6°
2030-12-05 Thu	60	—	unknown	04:10–04:20 (good, 0.17 h)	42.9° 01:00	11.39	86%	60.0°
2030-12-06 Fri	37	—	unknown	22:00–04:40 (marginal, 6.67 h)	42.9° 00:55	11.41	92%	50.0°
2030-12-07 Sat	23	—	unknown	00:00–04:15 (marginal, 4.25 h)	42.9° 00:50	11.42	96%	40.8°
2030-12-08 Sun	14	—	unknown	03:05–03:40 (marginal, 0.58 h)	42.9° 00:45	11.43	99%	33.2°
2030-12-09 Mon	10	—	unknown	—	42.9° 00:45	11.44	100%	28.2°
2030-12-10 Tue	10	—	unknown	—	42.9° 00:40	11.45	99%	27.4°
2030-12-11 Wed	14	—	unknown	21:45–22:25 (marginal, 0.67 h)	42.9° 00:35	11.46	96%	31.1°
2030-12-12 Thu	25	—	unknown	21:10–02:00 (marginal, 4.83 h)	42.9° 00:30	11.47	92%	38.0°
2030-12-13 Fri	39	—	unknown	20:50–03:35 (marginal, 6.75 h)	42.9° 00:25	11.48	86%	46.7°
2030-12-14 Sat	63	—	unknown	21:10–21:20 (good, 0.17 h)	42.9° 00:25	11.49	79%	56.6°
2030-12-15 Sun	83	—	unknown	21:05–01:50 (good, 4.75 h)	42.9° 00:20	11.49	70%	67.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-11-16&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.