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: 01-10 (89), 01-11 (89), 01-12 (89), 01-13 (89), 01-14 (89) — by astronomy; check the weather when the night is within four days.

2034-01-03astronomy score per night — click a bar for that night2034-02-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-01-03 Tue	11	—	unknown	—	42.9° 23:05	11.43	99%	25.2°
2034-01-04 Wed	14	—	unknown	20:05–21:00 (marginal, 0.92 h)	42.9° 23:00	11.41	100%	32.3°
2034-01-05 Thu	26	—	unknown	19:30–00:20 (marginal, 4.83 h)	42.9° 22:55	11.4	98%	42.4°
2034-01-06 Fri	42	—	unknown	19:05–02:00 (marginal, 6.92 h)	42.9° 22:50	11.39	95%	53.5°
2034-01-07 Sat	81	—	unknown	19:35–21:55 (good, 2.33 h)	42.9° 22:50	11.37	89%	65.0°
2034-01-08 Sun	86	—	unknown	19:30–00:25 (good, 4.92 h)	42.9° 22:45	11.36	82%	76.5°
2034-01-09 Mon	88	—	unknown	19:25–01:30 (good, 6.08 h)	42.9° 22:40	11.34	74%	87.8°
2034-01-10 Tue	89	—	unknown	19:20–01:40 (good, 6.33 h)	42.9° 22:35	11.32	65%	98.8°
2034-01-11 Wed	89	—	unknown	19:20–01:45 (good, 6.42 h)	42.9° 22:30	11.3	56%	109.7°
2034-01-12 Thu	89	—	unknown	19:15–01:45 (good, 6.5 h)	42.9° 22:30	11.29	46%	120.3°
2034-01-13 Fri	89	—	unknown	19:10–01:45 (good, 6.58 h)	42.9° 22:25	11.27	37%	130.6°
2034-01-14 Sat	89	—	unknown	19:05–01:40 (good, 6.58 h)	42.9° 22:20	11.24	28%	140.3°
2034-01-15 Sun	89	—	unknown	19:00–01:35 (good, 6.58 h)	42.9° 22:15	11.22	20%	148.9°
2034-01-16 Mon	89	—	unknown	19:00–01:30 (good, 6.5 h)	42.9° 22:15	11.2	13%	154.9°
2034-01-17 Tue	89	—	unknown	19:00–01:30 (good, 6.5 h)	42.9° 22:10	11.18	7%	155.9°
2034-01-18 Wed	89	—	unknown	19:00–01:25 (good, 6.42 h)	42.9° 22:05	11.16	3%	151.0°
2034-01-19 Thu	89	—	unknown	19:00–01:20 (good, 6.33 h)	42.9° 22:00	11.13	0%	142.2°
2034-01-20 Fri	89	—	unknown	19:00–01:15 (good, 6.25 h)	42.9° 21:55	11.11	0%	131.3°
2034-01-21 Sat	89	—	unknown	19:00–01:10 (good, 6.17 h)	42.9° 21:55	11.08	3%	119.3°
2034-01-22 Sun	89	—	unknown	19:05–01:10 (good, 6.08 h)	42.9° 21:50	11.05	8%	106.8°
2034-01-23 Mon	89	—	unknown	19:05–01:05 (good, 6.0 h)	42.9° 21:45	11.03	15%	93.9°
2034-01-24 Tue	88	—	unknown	19:05–01:00 (good, 5.92 h)	42.9° 21:40	11.0	24%	81.0°
2034-01-25 Wed	85	—	unknown	19:05–00:55 (good, 5.83 h)	42.9° 21:35	10.97	34%	68.1°
2034-01-26 Thu	72	—	unknown	19:10–00:50 (good, 5.67 h)	42.9° 21:35	10.94	45%	55.5°
2034-01-27 Fri	55	—	unknown	22:05–00:15 (good, 2.17 h)	42.9° 21:30	10.91	57%	43.6°
2034-01-28 Sat	36	—	unknown	19:10–01:05 (marginal, 5.92 h)	42.9° 21:25	10.88	68%	33.0°
2034-01-29 Sun	23	—	unknown	19:10–00:45 (marginal, 5.58 h)	42.9° 21:20	10.85	78%	25.5°
2034-01-30 Mon	15	—	unknown	19:10–00:10 (marginal, 5.0 h)	42.9° 21:20	10.82	86%	24.0°
2034-01-31 Tue	12	—	unknown	19:15–19:35 (marginal, 0.33 h)	42.9° 21:15	10.79	93%	29.4°
2034-02-01 Wed	16	—	unknown	19:15–21:35 (marginal, 2.33 h)	42.9° 21:10	10.76	97%	38.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-01-03&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.