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: 11-14 (89), 11-15 (89), 11-16 (89), 11-17 (89), 11-18 (89) — by astronomy; check the weather when the night is within four days.

2044-11-09astronomy score per night — click a bar for that night2044-12-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-11-09 Wed	33	—	unknown	23:10–05:30 (marginal, 6.33 h)	42.9° 02:40	10.8	75%	40.4°
2044-11-10 Thu	52	—	unknown	22:50–05:35 (marginal, 6.75 h)	42.9° 02:35	10.83	65%	49.2°
2044-11-11 Fri	68	—	unknown	23:35–04:30 (good, 4.92 h)	42.9° 02:30	10.86	53%	59.5°
2044-11-12 Sat	83	—	unknown	23:15–05:25 (good, 6.17 h)	42.9° 02:25	10.89	42%	70.5°
2044-11-13 Sun	88	—	unknown	23:10–05:30 (good, 6.33 h)	42.9° 02:25	10.92	32%	81.8°
2044-11-14 Mon	89	—	unknown	23:05–05:35 (good, 6.5 h)	42.9° 02:20	10.95	22%	93.0°
2044-11-15 Tue	89	—	unknown	23:00–05:30 (good, 6.5 h)	42.9° 02:15	10.98	14%	104.0°
2044-11-16 Wed	89	—	unknown	23:00–05:30 (good, 6.5 h)	42.9° 02:10	11.01	8%	114.5°
2044-11-17 Thu	89	—	unknown	22:55–05:25 (good, 6.5 h)	42.9° 02:10	11.03	3%	124.5°
2044-11-18 Fri	89	—	unknown	22:50–05:25 (good, 6.58 h)	42.9° 02:05	11.06	1%	133.3°
2044-11-19 Sat	89	—	unknown	22:45–05:20 (good, 6.58 h)	42.9° 02:00	11.09	0%	140.6°
2044-11-20 Sun	89	—	unknown	22:40–05:15 (good, 6.58 h)	42.9° 01:55	11.11	2%	145.3°
2044-11-21 Mon	89	—	unknown	22:40–05:10 (good, 6.5 h)	42.9° 01:50	11.14	5%	146.5°
2044-11-22 Tue	89	—	unknown	22:35–05:05 (good, 6.5 h)	42.9° 01:50	11.16	10%	144.0°
2044-11-23 Wed	89	—	unknown	22:30–05:05 (good, 6.58 h)	42.9° 01:45	11.18	16%	138.6°
2044-11-24 Thu	89	—	unknown	22:25–05:00 (good, 6.58 h)	42.9° 01:40	11.2	24%	131.3°
2044-11-25 Fri	89	—	unknown	22:20–04:55 (good, 6.58 h)	42.9° 01:35	11.23	32%	122.7°
2044-11-26 Sat	89	—	unknown	22:25–04:50 (good, 6.42 h)	42.9° 01:30	11.25	41%	113.4°
2044-11-27 Sun	89	—	unknown	22:25–04:50 (good, 6.42 h)	42.9° 01:30	11.27	51%	103.6°
2044-11-28 Mon	89	—	unknown	22:30–04:45 (good, 6.25 h)	42.9° 01:25	11.29	61%	93.4°
2044-11-29 Tue	88	—	unknown	22:35–04:40 (good, 6.08 h)	42.9° 01:20	11.31	70%	82.8°
2044-11-30 Wed	84	—	unknown	00:05–04:35 (good, 4.5 h)	42.9° 01:15	11.32	80%	72.0°
2044-12-01 Thu	62	—	unknown	04:20–04:30 (good, 0.17 h)	42.9° 01:15	11.34	88%	61.1°
2044-12-02 Fri	35	—	unknown	22:15–04:50 (marginal, 6.58 h)	42.9° 01:10	11.36	94%	50.7°
2044-12-03 Sat	20	—	unknown	01:00–04:25 (marginal, 3.42 h)	42.9° 01:05	11.37	98%	41.5°
2044-12-04 Sun	12	—	unknown	—	42.9° 01:00	11.39	100%	35.1°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-11-09&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.