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 (47), 03-11 (41), 03-12 (35), 03-13 (29), 03-23 (25) — by astronomy; check the weather when the night is within four days.

2046-03-10astronomy score per night — click a bar for that night2046-04-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-03-10 Sat	47	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.22	9%	64.9°
2046-03-11 Sun	41	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:40	9.17	15%	55.4°
2046-03-12 Mon	35	—	unknown	20:00–21:45 (good, 1.75 h)	42.9° 18:35	9.12	23%	46.6°
2046-03-13 Tue	29	—	unknown	20:00–21:30 (good, 1.5 h)	42.9° 18:35	9.07	32%	39.1°
2046-03-14 Wed	22	—	unknown	20:00–20:20 (good, 0.33 h)	42.9° 18:30	9.02	42%	33.9°
2046-03-15 Thu	15	—	unknown	20:05–22:05 (marginal, 2.0 h)	42.9° 18:25	8.97	52%	32.7°
2046-03-16 Fri	11	—	unknown	20:05–21:50 (marginal, 1.75 h)	42.9° 18:20	8.92	63%	36.1°
2046-03-17 Sat	9	—	unknown	20:05–21:35 (marginal, 1.5 h)	42.9° 18:15	8.87	74%	43.4°
2046-03-18 Sun	9	—	unknown	20:05–21:30 (marginal, 1.42 h)	42.9° 18:15	8.82	83%	53.4°
2046-03-19 Mon	10	—	unknown	20:10–21:35 (marginal, 1.42 h)	42.9° 18:10	8.77	91%	64.9°
2046-03-20 Tue	13	—	unknown	20:10–21:40 (marginal, 1.5 h)	42.9° 18:05	8.71	97%	77.3°
2046-03-21 Wed	16	—	unknown	20:10–20:25 (good, 0.25 h)	42.9° 18:00	8.66	100%	90.1°
2046-03-22 Thu	19	—	unknown	20:10–20:55 (good, 0.75 h)	42.9° 17:55	8.61	99%	102.8°
2046-03-23 Fri	25	—	unknown	20:15–21:00 (good, 0.75 h)	42.9° 17:55	8.56	96%	115.2°
2046-03-24 Sat	25	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:50	8.5	90%	126.6°
2046-03-25 Sun	24	—	unknown	21:15–22:05 (good, 0.83 h)	42.9° 18:45	8.45	83%	136.4°
2046-03-26 Mon	22	—	unknown	21:15–22:00 (good, 0.75 h)	42.9° 18:40	8.4	74%	143.8°
2046-03-27 Tue	20	—	unknown	21:20–21:55 (good, 0.58 h)	42.9° 18:40	8.35	64%	147.3°
2046-03-28 Wed	19	—	unknown	21:20–21:55 (good, 0.58 h)	42.9° 18:35	8.29	54%	146.4°
2046-03-29 Thu	17	—	unknown	21:20–21:50 (good, 0.5 h)	42.9° 18:30	8.24	44%	141.6°
2046-03-30 Fri	15	—	unknown	21:20–21:45 (good, 0.42 h)	42.9° 18:25	8.18	34%	134.5°
2046-03-31 Sat	12	—	unknown	21:25–21:40 (good, 0.25 h)	42.9° 18:20	8.13	25%	126.0°
2046-04-01 Sun	11	—	unknown	21:25–21:35 (good, 0.17 h)	42.9° 18:20	8.07	18%	116.7°
2046-04-02 Mon	10	—	unknown	21:25–21:35 (good, 0.17 h)	42.9° 18:15	8.02	11%	107.1°
2046-04-03 Tue	8	—	unknown	21:25–21:30 (good, 0.08 h)	42.9° 18:10	7.96	6%	97.2°
2046-04-04 Wed	7	—	unknown	21:30–21:55 (marginal, 0.42 h)	42.9° 18:05	7.91	2%	87.3°
2046-04-05 Thu	6	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:00	7.85	0%	77.2°
2046-04-06 Fri	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:00	7.8	0%	67.3°
2046-04-07 Sat	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	42.9° 17:55	7.74	2%	57.6°
2046-04-08 Sun	3	—	unknown	21:35–21:40 (marginal, 0.08 h)	42.9° 17:50	7.68	6%	48.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-03-10&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.