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: 03-10 (49), 03-11 (47), 03-12 (45), 03-13 (43), 03-14 (42) — by astronomy; check the weather when the night is within four days.

2045-03-10astronomy score per night — click a bar for that night2045-04-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-03-10 Fri	49	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.2	46%	146.4°
2045-03-11 Sat	47	—	unknown	20:00–22:00 (good, 2.0 h)	42.9° 18:40	9.16	37%	144.3°
2045-03-12 Sun	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.11	28%	139.2°
2045-03-13 Mon	43	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.06	20%	132.0°
2045-03-14 Tue	42	—	unknown	20:00–21:45 (good, 1.75 h)	42.9° 18:30	9.01	13%	123.6°
2045-03-15 Wed	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.96	7%	114.3°
2045-03-16 Thu	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.91	3%	104.5°
2045-03-17 Fri	36	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.86	1%	94.4°
2045-03-18 Sat	35	—	unknown	20:05–21:30 (good, 1.42 h)	42.9° 18:10	8.8	0%	84.0°
2045-03-19 Sun	33	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:10	8.75	2%	73.6°
2045-03-20 Mon	31	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.7	5%	63.3°
2045-03-21 Tue	28	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 18:00	8.65	11%	53.3°
2045-03-22 Wed	23	—	unknown	20:10–21:05 (good, 0.92 h)	42.9° 17:55	8.6	18%	44.4°
2045-03-23 Thu	19	—	unknown	20:15–20:55 (good, 0.67 h)	42.9° 17:50	8.54	27%	37.3°
2045-03-24 Fri	14	—	unknown	20:15–20:25 (good, 0.17 h)	42.9° 17:50	8.49	38%	33.7°
2045-03-25 Sat	10	—	unknown	20:15–21:30 (marginal, 1.25 h)	42.9° 17:45	8.44	49%	34.8°
2045-03-26 Sun	7	—	unknown	21:15–22:15 (marginal, 1.0 h)	42.9° 18:40	8.39	60%	40.4°
2045-03-27 Mon	6	—	unknown	21:20–22:05 (marginal, 0.75 h)	42.9° 18:35	8.33	71%	49.2°
2045-03-28 Tue	5	—	unknown	21:20–22:00 (marginal, 0.67 h)	42.9° 18:35	8.28	81%	59.7°
2045-03-29 Wed	6	—	unknown	21:20–22:00 (marginal, 0.67 h)	42.9° 18:30	8.22	89%	71.3°
2045-03-30 Thu	6	—	unknown	21:20–22:05 (marginal, 0.75 h)	42.9° 18:25	8.17	95%	83.2°
2045-03-31 Fri	7	—	unknown	21:25–22:10 (marginal, 0.75 h)	42.9° 18:20	8.12	99%	95.3°
2045-04-01 Sat	8	—	unknown	21:25–22:05 (marginal, 0.67 h)	42.9° 18:15	8.06	100%	107.0°
2045-04-02 Sun	8	—	unknown	20:50–22:05 (marginal, 1.25 h)	42.9° 18:15	8.01	98%	118.2°
2045-04-03 Mon	7	—	unknown	20:55–22:00 (marginal, 1.08 h)	42.9° 18:10	7.95	94%	128.4°
2045-04-04 Tue	6	—	unknown	21:30–21:55 (marginal, 0.42 h)	42.9° 18:05	7.89	88%	137.1°
2045-04-05 Wed	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:00	7.84	81%	143.4°
2045-04-06 Thu	4	—	unknown	21:30–21:45 (marginal, 0.25 h)	42.9° 17:55	7.78	72%	146.4°
2045-04-07 Fri	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	42.9° 17:55	7.73	63%	145.6°
2045-04-08 Sat	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	42.9° 17:50	7.67	54%	141.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-03-10&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.