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: 12-11 (89), 12-12 (89), 12-13 (89), 12-14 (89), 12-15 (89) — by astronomy; check the weather when the night is within four days.

2044-12-05astronomy score per night — click a bar for that night2045-01-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-12-05 Mon	11	—	unknown	—	42.9° 00:55	11.4	98%	33.6°
2044-12-06 Tue	18	—	unknown	21:50–00:20 (marginal, 2.5 h)	42.9° 00:55	11.42	94%	37.8°
2044-12-07 Wed	32	—	unknown	21:15–03:50 (marginal, 6.58 h)	42.9° 00:50	11.43	88%	46.0°
2044-12-08 Thu	52	—	unknown	21:00–04:10 (marginal, 7.17 h)	42.9° 00:45	11.44	79%	56.3°
2044-12-09 Fri	81	—	unknown	21:25–02:10 (good, 4.75 h)	42.9° 00:40	11.45	68%	67.6°
2044-12-10 Sat	87	—	unknown	21:25–03:30 (good, 6.08 h)	42.9° 00:35	11.46	58%	79.0°
2044-12-11 Sun	89	—	unknown	21:20–03:40 (good, 6.33 h)	42.9° 00:35	11.47	47%	90.4°
2044-12-12 Mon	89	—	unknown	21:15–03:40 (good, 6.42 h)	42.9° 00:30	11.48	36%	101.5°
2044-12-13 Tue	89	—	unknown	21:10–03:40 (good, 6.5 h)	42.9° 00:25	11.48	26%	112.1°
2044-12-14 Wed	89	—	unknown	21:05–03:40 (good, 6.58 h)	42.9° 00:20	11.49	18%	122.1°
2044-12-15 Thu	89	—	unknown	21:05–03:35 (good, 6.5 h)	42.9° 00:20	11.49	11%	131.2°
2044-12-16 Fri	89	—	unknown	21:00–03:35 (good, 6.58 h)	42.9° 00:15	11.5	6%	138.9°
2044-12-17 Sat	89	—	unknown	20:55–03:30 (good, 6.58 h)	42.9° 00:10	11.5	2%	144.3°
2044-12-18 Sun	89	—	unknown	20:50–03:25 (good, 6.58 h)	42.9° 00:05	11.51	0%	146.5°
2044-12-19 Mon	89	—	unknown	20:50–03:20 (good, 6.5 h)	42.9° 00:00	11.51	0%	145.1°
2044-12-20 Tue	89	—	unknown	20:45–03:15 (good, 6.5 h)	42.9° 00:00	11.51	2%	140.4°
2044-12-21 Wed	89	—	unknown	20:40–03:15 (good, 6.58 h)	42.9° 23:55	11.51	6%	133.5°
2044-12-22 Thu	89	—	unknown	20:35–03:10 (good, 6.58 h)	42.9° 23:50	11.51	11%	125.3°
2044-12-23 Fri	89	—	unknown	20:35–03:05 (good, 6.5 h)	42.9° 23:45	11.5	17%	116.2°
2044-12-24 Sat	89	—	unknown	20:30–03:00 (good, 6.5 h)	42.9° 23:40	11.5	25%	106.6°
2044-12-25 Sun	89	—	unknown	20:30–03:00 (good, 6.5 h)	42.9° 23:40	11.5	34%	96.6°
2044-12-26 Mon	89	—	unknown	20:35–02:55 (good, 6.33 h)	42.9° 23:35	11.49	44%	86.4°
2044-12-27 Tue	86	—	unknown	20:45–02:50 (good, 6.08 h)	42.9° 23:30	11.49	54%	75.9°
2044-12-28 Wed	81	—	unknown	21:50–02:45 (good, 4.92 h)	42.9° 23:25	11.48	64%	65.4°
2044-12-29 Thu	56	—	unknown	20:00–03:15 (marginal, 7.25 h)	42.9° 23:25	11.47	74%	55.1°
2044-12-30 Fri	36	—	unknown	20:15–03:00 (marginal, 6.75 h)	42.9° 23:20	11.47	83%	45.4°
2044-12-31 Sat	21	—	unknown	22:35–02:30 (marginal, 3.92 h)	42.9° 23:15	11.46	91%	37.6°
2045-01-01 Sun	12	—	unknown	—	42.9° 23:10	11.45	96%	33.6°
2045-01-02 Mon	12	—	unknown	—	42.9° 23:05	11.43	100%	35.2°
2045-01-03 Tue	19	—	unknown	19:55–22:55 (marginal, 3.0 h)	42.9° 23:05	11.42	100%	42.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-12-05&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.