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: 02-26 (71), 02-27 (66), 02-28 (60), 03-01 (52), 03-02 (44) — by astronomy; check the weather when the night is within four days.

2047-02-26astronomy score per night — click a bar for that night2047-03-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2047-03-09 Sat	14	—	unknown	19:55–22:05 (marginal, 2.17 h)	42.9° 18:50	9.28	94%	60.3°
2047-03-10 Sun	18	—	unknown	19:55–22:15 (marginal, 2.33 h)	42.9° 18:45	9.23	98%	72.3°
2047-03-11 Mon	24	—	unknown	20:00–20:30 (good, 0.5 h)	42.9° 18:40	9.18	100%	84.9°
2047-03-12 Tue	31	—	unknown	20:00–21:30 (good, 1.5 h)	42.9° 18:40	9.13	99%	97.8°
2047-03-13 Wed	41	—	unknown	20:00–21:40 (good, 1.67 h)	42.9° 18:35	9.08	95%	110.5°
2047-03-14 Thu	42	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.03	88%	122.7°
2047-03-15 Fri	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.98	79%	133.7°
2047-03-16 Sat	39	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.93	69%	142.7°
2047-03-17 Sun	38	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:20	8.88	58%	148.0°
2047-03-18 Mon	36	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.83	47%	148.4°
2047-03-19 Tue	33	—	unknown	20:10–21:30 (good, 1.33 h)	42.9° 18:10	8.78	37%	144.0°
2047-03-20 Wed	32	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.73	27%	136.5°
2047-03-21 Thu	30	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:00	8.67	18%	127.4°
2047-03-22 Fri	29	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 18:00	8.62	12%	117.6°
2047-03-23 Sat	27	—	unknown	20:15–21:15 (good, 1.0 h)	42.9° 17:55	8.57	6%	107.4°
2047-03-24 Sun	25	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:50	8.52	2%	97.1°
2047-03-25 Mon	24	—	unknown	20:15–21:05 (good, 0.83 h)	42.9° 17:45	8.46	0%	86.9°
2047-03-26 Tue	23	—	unknown	20:15–21:00 (good, 0.75 h)	42.9° 17:45	8.41	0%	76.7°
2047-03-27 Wed	21	—	unknown	20:20–21:00 (good, 0.67 h)	42.9° 17:40	8.36	2%	66.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-02-26&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.