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: 03-12 (45), 03-13 (44), 03-14 (42), 03-15 (40), 03-16 (38) — by astronomy; check the weather when the night is within four days.

2034-03-12astronomy score per night — click a bar for that night2034-04-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-03-12 Sun	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.12	53%	156.1°
2034-03-13 Mon	44	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.07	44%	155.4°
2034-03-14 Tue	42	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.02	34%	149.5°
2034-03-15 Wed	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.97	24%	140.3°
2034-03-16 Thu	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.92	16%	129.3°
2034-03-17 Fri	37	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.87	8%	117.1°
2034-03-18 Sat	36	—	unknown	20:05–21:30 (good, 1.42 h)	42.9° 18:15	8.82	3%	104.2°
2034-03-19 Sun	33	—	unknown	20:10–21:30 (good, 1.33 h)	42.9° 18:10	8.77	0%	90.8°
2034-03-20 Mon	32	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.72	0%	77.1°
2034-03-21 Tue	30	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:00	8.67	3%	63.5°
2034-03-22 Wed	27	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 17:55	8.61	9%	50.4°
2034-03-23 Thu	22	—	unknown	20:15–21:05 (good, 0.83 h)	42.9° 17:55	8.56	17%	38.3°
2034-03-24 Fri	17	—	unknown	20:15–20:50 (good, 0.58 h)	42.9° 17:50	8.51	27%	28.5°
2034-03-25 Sat	13	—	unknown	20:15–20:25 (good, 0.17 h)	42.9° 17:45	8.46	38%	23.6°
2034-03-26 Sun	9	—	unknown	21:15–22:25 (marginal, 1.17 h)	42.9° 18:40	8.4	49%	25.9°
2034-03-27 Mon	7	—	unknown	21:20–22:10 (marginal, 0.83 h)	42.9° 18:35	8.35	60%	33.6°
2034-03-28 Tue	5	—	unknown	21:20–22:00 (marginal, 0.67 h)	42.9° 18:35	8.3	70%	43.7°
2034-03-29 Wed	5	—	unknown	21:20–21:55 (marginal, 0.58 h)	42.9° 18:30	8.24	79%	54.6°
2034-03-30 Thu	5	—	unknown	21:20–21:55 (marginal, 0.58 h)	42.9° 18:25	8.19	86%	65.8°
2034-03-31 Fri	5	—	unknown	21:25–22:00 (marginal, 0.58 h)	42.9° 18:20	8.13	92%	77.1°
2034-04-01 Sat	6	—	unknown	21:25–22:05 (marginal, 0.67 h)	42.9° 18:20	8.08	97%	88.3°
2034-04-02 Sun	6	—	unknown	21:25–22:05 (marginal, 0.67 h)	42.9° 18:15	8.02	99%	99.4°
2034-04-03 Mon	6	—	unknown	21:25–22:00 (marginal, 0.58 h)	42.9° 18:10	7.97	100%	110.3°
2034-04-04 Tue	5	—	unknown	21:30–21:55 (marginal, 0.42 h)	42.9° 18:05	7.91	99%	121.0°
2034-04-05 Wed	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:00	7.86	96%	131.3°
2034-04-06 Thu	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:00	7.8	91%	141.0°
2034-04-07 Fri	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	42.9° 17:55	7.75	85%	149.4°
2034-04-08 Sat	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	42.9° 17:50	7.69	78%	155.2°
2034-04-09 Sun	2	—	unknown	21:00–21:05 (marginal, 0.08 h)	42.9° 17:45	7.63	70%	156.3°
2034-04-10 Mon	2	—	unknown	—	42.9° 17:40	7.58	60%	151.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-03-12&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.