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

2041-11-16astronomy score per night — click a bar for that night2041-12-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-11-16 Sat	86	—	unknown	23:00–05:15 (good, 6.25 h)	42.9° 02:15	11.0	38%	79.6°
2041-11-17 Sun	88	—	unknown	22:55–05:20 (good, 6.42 h)	42.9° 02:10	11.03	29%	89.5°
2041-11-18 Mon	89	—	unknown	22:50–05:20 (good, 6.5 h)	42.9° 02:05	11.05	21%	99.5°
2041-11-19 Tue	89	—	unknown	22:45–05:20 (good, 6.58 h)	42.9° 02:00	11.08	14%	109.5°
2041-11-20 Wed	89	—	unknown	22:45–05:15 (good, 6.5 h)	42.9° 01:55	11.1	8%	119.4°
2041-11-21 Thu	89	—	unknown	22:40–05:10 (good, 6.5 h)	42.9° 01:55	11.13	3%	128.8°
2041-11-22 Fri	89	—	unknown	22:35–05:10 (good, 6.58 h)	42.9° 01:50	11.15	1%	137.3°
2041-11-23 Sat	89	—	unknown	22:30–05:05 (good, 6.58 h)	42.9° 01:45	11.18	0%	144.0°
2041-11-24 Sun	89	—	unknown	22:25–05:00 (good, 6.58 h)	42.9° 01:40	11.2	2%	147.4°
2041-11-25 Mon	89	—	unknown	22:25–04:55 (good, 6.5 h)	42.9° 01:35	11.22	6%	146.2°
2041-11-26 Tue	89	—	unknown	22:20–04:50 (good, 6.5 h)	42.9° 01:35	11.24	12%	140.6°
2041-11-27 Wed	89	—	unknown	22:15–04:50 (good, 6.58 h)	42.9° 01:30	11.26	20%	132.1°
2041-11-28 Thu	89	—	unknown	22:10–04:45 (good, 6.58 h)	42.9° 01:25	11.28	29%	121.8°
2041-11-29 Fri	89	—	unknown	22:10–04:40 (good, 6.5 h)	42.9° 01:20	11.3	40%	110.6°
2041-11-30 Sat	89	—	unknown	22:15–04:35 (good, 6.33 h)	42.9° 01:20	11.32	51%	98.9°
2041-12-01 Sun	89	—	unknown	22:20–04:35 (good, 6.25 h)	42.9° 01:15	11.34	62%	87.0°
2041-12-02 Mon	87	—	unknown	22:55–04:30 (good, 5.58 h)	42.9° 01:10	11.35	73%	75.1°
2041-12-03 Tue	82	—	unknown	01:20–04:25 (good, 3.08 h)	42.9° 01:05	11.37	83%	63.5°
2041-12-04 Wed	43	—	unknown	21:55–04:50 (marginal, 6.92 h)	42.9° 01:00	11.38	90%	52.5°
2041-12-05 Thu	26	—	unknown	23:20–04:30 (marginal, 5.17 h)	42.9° 01:00	11.4	96%	42.9°
2041-12-06 Fri	15	—	unknown	02:50–03:50 (marginal, 1.0 h)	42.9° 00:55	11.41	99%	35.7°
2041-12-07 Sat	10	—	unknown	—	42.9° 00:50	11.42	100%	32.5°
2041-12-08 Sun	12	—	unknown	—	42.9° 00:45	11.44	98%	34.1°
2041-12-09 Mon	19	—	unknown	21:35–00:45 (marginal, 3.17 h)	42.9° 00:40	11.45	94%	39.6°
2041-12-10 Tue	32	—	unknown	21:05–03:35 (marginal, 6.5 h)	42.9° 00:40	11.46	89%	47.6°
2041-12-11 Wed	48	—	unknown	20:50–03:55 (marginal, 7.08 h)	42.9° 00:35	11.47	82%	56.6°
2041-12-12 Thu	67	—	unknown	21:40–01:00 (good, 3.33 h)	42.9° 00:30	11.47	74%	66.3°
2041-12-13 Fri	84	—	unknown	21:10–02:55 (good, 5.75 h)	42.9° 00:25	11.48	65%	76.1°
2041-12-14 Sat	88	—	unknown	21:10–03:20 (good, 6.17 h)	42.9° 00:25	11.49	56%	86.1°
2041-12-15 Sun	89	—	unknown	21:05–03:25 (good, 6.33 h)	42.9° 00:20	11.49	47%	96.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-11-16&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.