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: 11-22 (89), 11-23 (89), 11-24 (89), 11-25 (89), 11-26 (89) — by astronomy; check the weather when the night is within four days.

2046-11-13astronomy score per night — click a bar for that night2046-12-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-11-13 Tue	21	—	unknown	02:00–05:35 (marginal, 3.58 h)	42.9° 02:25	10.91	100%	43.3°
2046-11-14 Wed	14	—	unknown	04:25–05:15 (marginal, 0.83 h)	42.9° 02:20	10.93	98%	36.3°
2046-11-15 Thu	12	—	unknown	—	42.9° 02:20	10.96	95%	32.0°
2046-11-16 Fri	15	—	unknown	23:25–00:10 (marginal, 0.75 h)	42.9° 02:15	10.99	90%	31.9°
2046-11-17 Sat	26	—	unknown	22:50–05:05 (marginal, 6.25 h)	42.9° 02:10	11.02	83%	36.2°
2046-11-18 Sun	41	—	unknown	22:25–05:25 (marginal, 7.0 h)	42.9° 02:05	11.05	74%	43.7°
2046-11-19 Mon	61	—	unknown	23:20–01:35 (good, 2.25 h)	42.9° 02:00	11.07	64%	53.2°
2046-11-20 Tue	81	—	unknown	22:45–04:25 (good, 5.67 h)	42.9° 02:00	11.1	54%	64.0°
2046-11-21 Wed	86	—	unknown	22:40–04:55 (good, 6.25 h)	42.9° 01:55	11.12	43%	75.5°
2046-11-22 Thu	89	—	unknown	22:35–05:00 (good, 6.42 h)	42.9° 01:50	11.15	32%	87.6°
2046-11-23 Fri	89	—	unknown	22:30–05:00 (good, 6.5 h)	42.9° 01:45	11.17	21%	99.9°
2046-11-24 Sat	89	—	unknown	22:30–05:00 (good, 6.5 h)	42.9° 01:40	11.19	12%	112.2°
2046-11-25 Sun	89	—	unknown	22:25–04:55 (good, 6.5 h)	42.9° 01:40	11.22	6%	124.1°
2046-11-26 Mon	89	—	unknown	22:20–04:55 (good, 6.58 h)	42.9° 01:35	11.24	2%	134.9°
2046-11-27 Tue	89	—	unknown	22:15–04:50 (good, 6.58 h)	42.9° 01:30	11.26	0%	143.5°
2046-11-28 Wed	89	—	unknown	22:10–04:45 (good, 6.58 h)	42.9° 01:25	11.28	1%	148.2°
2046-11-29 Thu	89	—	unknown	22:10–04:40 (good, 6.5 h)	42.9° 01:25	11.3	5%	147.5°
2046-11-30 Fri	89	—	unknown	22:05–04:40 (good, 6.58 h)	42.9° 01:20	11.32	11%	142.1°
2046-12-01 Sat	89	—	unknown	22:00–04:35 (good, 6.58 h)	42.9° 01:15	11.33	19%	133.9°
2046-12-02 Sun	89	—	unknown	21:55–04:30 (good, 6.58 h)	42.9° 01:10	11.35	27%	124.5°
2046-12-03 Mon	89	—	unknown	21:55–04:25 (good, 6.5 h)	42.9° 01:05	11.37	36%	114.6°
2046-12-04 Tue	89	—	unknown	21:55–04:20 (good, 6.42 h)	42.9° 01:05	11.38	46%	104.4°
2046-12-05 Wed	89	—	unknown	22:00–04:20 (good, 6.33 h)	42.9° 01:00	11.4	56%	94.3°
2046-12-06 Thu	88	—	unknown	22:10–04:15 (good, 6.08 h)	42.9° 00:55	11.41	65%	84.2°
2046-12-07 Fri	85	—	unknown	23:00–04:10 (good, 5.17 h)	42.9° 00:50	11.42	74%	74.2°
2046-12-08 Sat	74	—	unknown	01:20–03:35 (good, 2.25 h)	42.9° 00:45	11.43	81%	64.3°
2046-12-09 Sun	44	—	unknown	21:35–04:30 (marginal, 6.92 h)	42.9° 00:45	11.44	88%	54.8°
2046-12-10 Mon	29	—	unknown	22:00–04:15 (marginal, 6.25 h)	42.9° 00:40	11.45	94%	45.8°
2046-12-11 Tue	18	—	unknown	01:30–03:45 (marginal, 2.25 h)	42.9° 00:35	11.46	98%	38.2°
2046-12-12 Wed	11	—	unknown	—	42.9° 00:30	11.47	100%	32.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-11-13&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.