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: 03-05 (58), 03-04 (57), 03-06 (56), 03-03 (54), 03-07 (54) — by astronomy; check the weather when the night is within four days.

2037-03-03astronomy score per night — click a bar for that night2037-04-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-03-03 Tue	54	—	unknown	19:50–22:10 (good, 2.33 h)	42.9° 19:10	9.54	94%	107.9°
2037-03-04 Wed	57	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:05	9.49	88%	121.0°
2037-03-05 Thu	58	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:05	9.45	79%	133.1°
2037-03-06 Fri	56	—	unknown	19:50–22:20 (good, 2.5 h)	42.9° 19:00	9.4	69%	143.7°
2037-03-07 Sat	54	—	unknown	19:55–22:15 (good, 2.33 h)	42.9° 18:55	9.35	59%	151.6°
2037-03-08 Sun	52	—	unknown	19:55–22:10 (good, 2.25 h)	42.9° 18:50	9.3	49%	155.0°
2037-03-09 Mon	50	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.26	39%	152.6°
2037-03-10 Tue	49	—	unknown	19:55–22:00 (good, 2.08 h)	42.9° 18:45	9.21	29%	146.0°
2037-03-11 Wed	47	—	unknown	20:00–22:00 (good, 2.0 h)	42.9° 18:40	9.16	21%	137.3°
2037-03-12 Thu	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.11	14%	127.5°
2037-03-13 Fri	43	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.06	8%	117.3°
2037-03-14 Sat	42	—	unknown	20:00–21:45 (good, 1.75 h)	42.9° 18:30	9.01	4%	106.8°
2037-03-15 Sun	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.96	1%	96.1°
2037-03-16 Mon	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.91	0%	85.4°
2037-03-17 Tue	36	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.86	1%	74.6°
2037-03-18 Wed	35	—	unknown	20:05–21:30 (good, 1.42 h)	42.9° 18:10	8.81	4%	63.9°
2037-03-19 Thu	32	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:10	8.76	8%	53.3°
2037-03-20 Fri	28	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 18:05	8.7	14%	43.2°
2037-03-21 Sat	23	—	unknown	20:10–21:05 (good, 0.92 h)	42.9° 18:00	8.65	22%	34.1°
2037-03-22 Sun	18	—	unknown	20:10–20:50 (good, 0.67 h)	42.9° 17:55	8.6	31%	27.3°
2037-03-23 Mon	13	—	unknown	20:15–21:40 (marginal, 1.42 h)	42.9° 17:50	8.55	41%	25.2°
2037-03-24 Tue	10	—	unknown	20:15–21:30 (marginal, 1.25 h)	42.9° 17:50	8.5	52%	29.2°
2037-03-25 Wed	7	—	unknown	20:15–21:15 (marginal, 1.0 h)	42.9° 17:45	8.44	63%	37.7°
2037-03-26 Thu	6	—	unknown	20:15–21:05 (marginal, 0.83 h)	42.9° 17:40	8.39	73%	48.8°
2037-03-27 Fri	6	—	unknown	20:20–21:05 (marginal, 0.75 h)	42.9° 17:35	8.34	83%	61.2°
2037-03-28 Sat	7	—	unknown	20:20–21:05 (marginal, 0.75 h)	42.9° 17:35	8.28	91%	74.3°
2037-03-29 Sun	8	—	unknown	21:20–22:10 (marginal, 0.83 h)	42.9° 18:30	8.23	97%	87.9°
2037-03-30 Mon	9	—	unknown	21:20–22:15 (marginal, 0.92 h)	42.9° 18:25	8.17	100%	101.6°
2037-03-31 Tue	9	—	unknown	20:50–22:10 (marginal, 1.33 h)	42.9° 18:20	8.12	99%	115.0°
2037-04-01 Wed	9	—	unknown	21:25–21:30 (good, 0.08 h)	42.9° 18:15	8.06	96%	127.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-03-03&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.