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: 02-14 (89), 02-15 (88), 02-16 (87), 02-13 (86), 02-17 (86) — by astronomy; check the weather when the night is within four days.

2047-02-07astronomy score per night — click a bar for that night2047-03-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-02-07 Thu	13	—	unknown	19:20–20:55 (marginal, 1.58 h)	42.9° 20:45	10.55	91%	36.1°
2047-02-08 Fri	17	—	unknown	19:20–22:25 (marginal, 3.08 h)	42.9° 20:45	10.52	96%	44.0°
2047-02-09 Sat	24	—	unknown	19:25–23:35 (marginal, 4.17 h)	42.9° 20:40	10.48	99%	54.1°
2047-02-10 Sun	35	—	unknown	19:25–23:55 (marginal, 4.5 h)	42.9° 20:35	10.44	100%	65.6°
2047-02-11 Mon	50	—	unknown	19:25–21:30 (good, 2.08 h)	42.9° 20:30	10.41	98%	77.8°
2047-02-12 Tue	79	—	unknown	19:25–23:15 (good, 3.83 h)	42.9° 20:30	10.37	92%	90.3°
2047-02-13 Wed	86	—	unknown	19:30–23:25 (good, 3.92 h)	42.9° 20:25	10.33	85%	102.8°
2047-02-14 Thu	89	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:20	10.29	76%	114.9°
2047-02-15 Fri	88	—	unknown	19:30–23:35 (good, 4.08 h)	42.9° 20:15	10.25	65%	126.4°
2047-02-16 Sat	87	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:10	10.21	54%	136.5°
2047-02-17 Sun	86	—	unknown	19:30–23:25 (good, 3.92 h)	42.9° 20:10	10.17	43%	144.3°
2047-02-18 Mon	84	—	unknown	19:35–23:25 (good, 3.83 h)	42.9° 20:05	10.13	32%	148.4°
2047-02-19 Tue	82	—	unknown	19:35–23:20 (good, 3.75 h)	42.9° 20:00	10.09	22%	147.6°
2047-02-20 Wed	80	—	unknown	19:35–23:15 (good, 3.67 h)	42.9° 19:55	10.04	14%	142.3°
2047-02-21 Thu	79	—	unknown	19:35–23:10 (good, 3.58 h)	42.9° 19:50	10.0	8%	134.4°
2047-02-22 Fri	77	—	unknown	19:40–23:10 (good, 3.5 h)	42.9° 19:50	9.96	3%	125.0°
2047-02-23 Sat	75	—	unknown	19:40–23:05 (good, 3.42 h)	42.9° 19:45	9.92	1%	115.0°
2047-02-24 Sun	73	—	unknown	19:40–23:00 (good, 3.33 h)	42.9° 19:40	9.87	0%	104.7°
2047-02-25 Mon	72	—	unknown	19:40–22:55 (good, 3.25 h)	42.9° 19:35	9.83	1%	94.3°
2047-02-26 Tue	71	—	unknown	19:40–22:50 (good, 3.17 h)	42.9° 19:35	9.79	4%	84.1°
2047-02-27 Wed	66	—	unknown	19:45–22:50 (good, 3.08 h)	42.9° 19:30	9.74	9%	73.9°
2047-02-28 Thu	60	—	unknown	19:45–22:45 (good, 3.0 h)	42.9° 19:25	9.7	15%	64.1°
2047-03-01 Fri	52	—	unknown	19:45–22:30 (good, 2.75 h)	42.9° 19:20	9.65	23%	54.7°
2047-03-02 Sat	44	—	unknown	19:45–22:20 (good, 2.58 h)	42.9° 19:15	9.61	31%	46.0°
2047-03-03 Sun	34	—	unknown	19:50–22:05 (good, 2.25 h)	42.9° 19:15	9.56	40%	38.5°
2047-03-04 Mon	25	—	unknown	19:50–22:55 (marginal, 3.08 h)	42.9° 19:10	9.51	50%	33.1°
2047-03-05 Tue	18	—	unknown	19:50–22:40 (marginal, 2.83 h)	42.9° 19:05	9.47	60%	31.2°
2047-03-06 Wed	13	—	unknown	19:50–22:20 (marginal, 2.5 h)	42.9° 19:00	9.42	70%	33.8°
2047-03-07 Thu	11	—	unknown	19:55–22:05 (marginal, 2.17 h)	42.9° 18:55	9.37	79%	40.2°
2047-03-08 Fri	11	—	unknown	19:55–22:00 (marginal, 2.08 h)	42.9° 18:55	9.32	87%	49.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-02-07&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.