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), 12-03 (89), 12-04 (89) — by astronomy; check the weather when the night is within four days.

2034-11-18astronomy score per night — click a bar for that night2034-12-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-11-18 Sat	89	—	unknown	22:55–05:25 (good, 6.5 h)	42.9° 02:05	11.04	47%	116.6°
2034-11-19 Sun	89	—	unknown	23:00–05:20 (good, 6.33 h)	42.9° 02:00	11.07	58%	104.9°
2034-11-20 Mon	89	—	unknown	23:05–05:15 (good, 6.17 h)	42.9° 02:00	11.1	68%	92.7°
2034-11-21 Tue	88	—	unknown	23:30–05:15 (good, 5.75 h)	42.9° 01:55	11.12	78%	79.9°
2034-11-22 Wed	84	—	unknown	01:40–05:10 (good, 3.5 h)	42.9° 01:50	11.15	87%	66.9°
2034-11-23 Thu	52	—	unknown	05:00–05:05 (good, 0.08 h)	42.9° 01:45	11.17	94%	53.8°
2034-11-24 Fri	26	—	unknown	00:25–05:15 (marginal, 4.83 h)	42.9° 01:40	11.19	98%	41.1°
2034-11-25 Sat	14	—	unknown	04:00–04:30 (marginal, 0.5 h)	42.9° 01:40	11.21	100%	30.2°
2034-11-26 Sun	11	—	unknown	—	42.9° 01:35	11.24	98%	24.0°
2034-11-27 Mon	14	—	unknown	22:50–22:55 (marginal, 0.08 h)	42.9° 01:30	11.26	94%	26.0°
2034-11-28 Tue	25	—	unknown	22:05–03:45 (marginal, 5.67 h)	42.9° 01:25	11.28	87%	34.5°
2034-11-29 Wed	43	—	unknown	21:40–04:40 (marginal, 7.0 h)	42.9° 01:20	11.3	78%	45.6°
2034-11-30 Thu	63	—	unknown	22:30–01:25 (good, 2.92 h)	42.9° 01:20	11.31	68%	57.5°
2034-12-01 Fri	83	—	unknown	22:00–03:50 (good, 5.83 h)	42.9° 01:15	11.33	58%	69.5°
2034-12-02 Sat	88	—	unknown	21:55–04:10 (good, 6.25 h)	42.9° 01:10	11.35	48%	81.4°
2034-12-03 Sun	89	—	unknown	21:50–04:15 (good, 6.42 h)	42.9° 01:05	11.36	38%	92.9°
2034-12-04 Mon	89	—	unknown	21:50–04:15 (good, 6.42 h)	42.9° 01:05	11.38	28%	104.2°
2034-12-05 Tue	89	—	unknown	21:45–04:15 (good, 6.5 h)	42.9° 01:00	11.39	20%	115.1°
2034-12-06 Wed	89	—	unknown	21:40–04:15 (good, 6.58 h)	42.9° 00:55	11.41	13%	125.7°
2034-12-07 Thu	89	—	unknown	21:35–04:10 (good, 6.58 h)	42.9° 00:50	11.42	8%	135.8°
2034-12-08 Fri	89	—	unknown	21:35–04:05 (good, 6.5 h)	42.9° 00:45	11.43	3%	144.9°
2034-12-09 Sat	89	—	unknown	21:30–04:00 (good, 6.5 h)	42.9° 00:45	11.44	1%	152.3°
2034-12-10 Sun	89	—	unknown	21:25–04:00 (good, 6.58 h)	42.9° 00:40	11.45	0%	156.1°
2034-12-11 Mon	89	—	unknown	21:20–03:55 (good, 6.58 h)	42.9° 00:35	11.46	1%	154.8°
2034-12-12 Tue	89	—	unknown	21:15–03:50 (good, 6.58 h)	42.9° 00:30	11.47	4%	148.8°
2034-12-13 Wed	89	—	unknown	21:15–03:45 (good, 6.5 h)	42.9° 00:25	11.48	9%	140.2°
2034-12-14 Thu	89	—	unknown	21:10–03:45 (good, 6.58 h)	42.9° 00:25	11.49	15%	130.1°
2034-12-15 Fri	89	—	unknown	21:05–03:40 (good, 6.58 h)	42.9° 00:20	11.49	22%	119.3°
2034-12-16 Sat	89	—	unknown	21:05–03:35 (good, 6.5 h)	42.9° 00:15	11.5	31%	107.9°
2034-12-17 Sun	89	—	unknown	21:10–03:30 (good, 6.33 h)	42.9° 00:10	11.5	41%	96.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-11-18&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.