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

2047-12-04astronomy score per night — click a bar for that night2048-01-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2047-12-18 Wed	89	—	unknown	20:55–03:30 (good, 6.58 h)	42.9° 00:10	11.5	5%	140.2°
2047-12-19 Thu	89	—	unknown	20:50–03:25 (good, 6.58 h)	42.9° 00:05	11.51	12%	130.1°
2047-12-20 Fri	89	—	unknown	20:50–03:20 (good, 6.5 h)	42.9° 00:00	11.51	20%	119.2°
2047-12-21 Sat	89	—	unknown	20:45–03:15 (good, 6.5 h)	42.9° 23:55	11.51	29%	108.0°
2047-12-22 Sun	89	—	unknown	20:50–03:10 (good, 6.33 h)	42.9° 23:55	11.51	39%	97.0°
2047-12-23 Mon	88	—	unknown	20:55–03:10 (good, 6.25 h)	42.9° 23:50	11.51	48%	86.1°
2047-12-24 Tue	85	—	unknown	21:00–03:05 (good, 6.08 h)	42.9° 23:45	11.5	58%	75.6°
2047-12-25 Wed	80	—	unknown	22:30–03:00 (good, 4.5 h)	42.9° 23:40	11.5	68%	65.4°
2047-12-26 Thu	55	—	unknown	20:15–03:30 (marginal, 7.25 h)	42.9° 23:35	11.5	76%	55.7°
2047-12-27 Fri	38	—	unknown	20:30–03:15 (marginal, 6.75 h)	42.9° 23:35	11.49	84%	46.6°
2047-12-28 Sat	24	—	unknown	21:45–02:55 (marginal, 5.17 h)	42.9° 23:30	11.49	90%	38.6°
2047-12-29 Sun	14	—	unknown	01:55–02:15 (marginal, 0.33 h)	42.9° 23:25	11.48	95%	32.6°
2047-12-30 Mon	9	—	unknown	—	42.9° 23:20	11.47	98%	29.9°
2047-12-31 Tue	11	—	unknown	—	42.9° 23:20	11.46	100%	31.4°
2048-01-01 Wed	17	—	unknown	20:10–22:00 (marginal, 1.83 h)	42.9° 23:15	11.45	100%	36.8°
2048-01-02 Thu	28	—	unknown	19:40–01:10 (marginal, 5.5 h)	42.9° 23:10	11.44	97%	44.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-12-04&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.