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: 02-04 (89), 02-05 (89), 02-06 (89), 02-07 (89), 02-08 (89) — by astronomy; check the weather when the night is within four days.

2045-01-25astronomy score per night — click a bar for that night2045-02-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-01-25 Wed	70	—	unknown	19:10–00:40 (good, 5.5 h)	42.9° 21:35	10.96	47%	58.4°
2045-01-26 Thu	56	—	unknown	22:05–00:10 (good, 2.08 h)	42.9° 21:35	10.93	58%	48.8°
2045-01-27 Fri	37	—	unknown	19:10–01:10 (marginal, 6.0 h)	42.9° 21:30	10.9	68%	40.4°
2045-01-28 Sat	23	—	unknown	19:10–00:45 (marginal, 5.58 h)	42.9° 21:25	10.87	78%	34.8°
2045-01-29 Sun	14	—	unknown	19:10–20:30 (marginal, 1.33 h)	42.9° 21:20	10.84	87%	33.8°
2045-01-30 Mon	14	—	unknown	19:10–20:45 (marginal, 1.58 h)	42.9° 21:15	10.81	94%	38.3°
2045-01-31 Tue	20	—	unknown	19:15–22:55 (marginal, 3.67 h)	42.9° 21:15	10.78	99%	46.8°
2045-02-01 Wed	31	—	unknown	19:15–00:10 (marginal, 4.92 h)	42.9° 21:10	10.74	100%	57.7°
2045-02-02 Thu	46	—	unknown	19:15–19:40 (good, 0.42 h)	42.9° 21:05	10.71	98%	69.6°
2045-02-03 Fri	81	—	unknown	19:15–22:40 (good, 3.42 h)	42.9° 21:00	10.68	94%	81.9°
2045-02-04 Sat	89	—	unknown	19:20–23:50 (good, 4.5 h)	42.9° 20:55	10.64	87%	93.9°
2045-02-05 Sun	89	—	unknown	19:20–00:00 (good, 4.67 h)	42.9° 20:55	10.61	78%	105.6°
2045-02-06 Mon	89	—	unknown	19:20–00:00 (good, 4.67 h)	42.9° 20:50	10.57	69%	116.5°
2045-02-07 Tue	89	—	unknown	19:20–00:05 (good, 4.75 h)	42.9° 20:45	10.54	59%	126.4°
2045-02-08 Wed	89	—	unknown	19:20–00:00 (good, 4.67 h)	42.9° 20:40	10.5	48%	135.0°
2045-02-09 Thu	89	—	unknown	19:25–23:55 (good, 4.5 h)	42.9° 20:40	10.46	39%	141.8°
2045-02-10 Fri	89	—	unknown	19:25–23:55 (good, 4.5 h)	42.9° 20:35	10.42	30%	145.7°
2045-02-11 Sat	89	—	unknown	19:25–23:50 (good, 4.42 h)	42.9° 20:30	10.39	21%	146.1°
2045-02-12 Sun	89	—	unknown	19:25–23:45 (good, 4.33 h)	42.9° 20:25	10.35	14%	143.0°
2045-02-13 Mon	89	—	unknown	19:30–23:40 (good, 4.17 h)	42.9° 20:20	10.31	8%	137.2°
2045-02-14 Tue	89	—	unknown	19:30–23:35 (good, 4.08 h)	42.9° 20:20	10.27	4%	129.6°
2045-02-15 Wed	88	—	unknown	19:30–23:35 (good, 4.08 h)	42.9° 20:15	10.23	1%	120.9°
2045-02-16 Thu	86	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:10	10.19	0%	111.5°
2045-02-17 Fri	84	—	unknown	19:35–23:25 (good, 3.83 h)	42.9° 20:05	10.15	1%	101.7°
2045-02-18 Sat	82	—	unknown	19:35–23:20 (good, 3.75 h)	42.9° 20:00	10.11	4%	91.5°
2045-02-19 Sun	80	—	unknown	19:35–23:15 (good, 3.67 h)	42.9° 20:00	10.07	8%	81.3°
2045-02-20 Mon	74	—	unknown	19:35–23:15 (good, 3.67 h)	42.9° 19:55	10.02	14%	71.0°
2045-02-21 Tue	66	—	unknown	19:35–23:10 (good, 3.58 h)	42.9° 19:50	9.98	22%	60.8°
2045-02-22 Wed	54	—	unknown	19:40–22:50 (good, 3.17 h)	42.9° 19:45	9.94	32%	51.2°
2045-02-23 Thu	42	—	unknown	19:40–22:35 (good, 2.92 h)	42.9° 19:40	9.9	42%	42.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-01-25&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.