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: 11-26 (89), 11-27 (89), 11-28 (89), 11-29 (89), 11-30 (89) — by astronomy; check the weather when the night is within four days.

2038-11-26astronomy score per night — click a bar for that night2038-12-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-11-26 Fri	89	—	unknown	22:20–04:55 (good, 6.58 h)	42.9° 01:35	11.24	0%	150.4°
2038-11-27 Sat	89	—	unknown	22:15–04:50 (good, 6.58 h)	42.9° 01:30	11.26	3%	151.9°
2038-11-28 Sun	89	—	unknown	22:10–04:45 (good, 6.58 h)	42.9° 01:25	11.28	8%	146.7°
2038-11-29 Mon	89	—	unknown	22:10–04:40 (good, 6.5 h)	42.9° 01:20	11.3	15%	137.5°
2038-11-30 Tue	89	—	unknown	22:05–04:40 (good, 6.58 h)	42.9° 01:20	11.31	24%	126.8°
2038-12-01 Wed	89	—	unknown	22:00–04:35 (good, 6.58 h)	42.9° 01:15	11.33	34%	115.6°
2038-12-02 Thu	89	—	unknown	22:05–04:30 (good, 6.42 h)	42.9° 01:10	11.35	44%	104.4°
2038-12-03 Fri	89	—	unknown	22:05–04:25 (good, 6.33 h)	42.9° 01:05	11.37	54%	93.4°
2038-12-04 Sat	89	—	unknown	22:15–04:20 (good, 6.08 h)	42.9° 01:05	11.38	64%	82.5°
2038-12-05 Sun	87	—	unknown	22:55–04:20 (good, 5.42 h)	42.9° 01:00	11.39	72%	72.0°
2038-12-06 Mon	82	—	unknown	00:55–04:15 (good, 3.33 h)	42.9° 00:55	11.41	80%	61.7°
2038-12-07 Tue	54	—	unknown	04:05–04:10 (good, 0.08 h)	42.9° 00:50	11.42	87%	51.9°
2038-12-08 Wed	32	—	unknown	22:05–04:25 (marginal, 6.33 h)	42.9° 00:45	11.43	93%	42.8°
2038-12-09 Thu	19	—	unknown	01:15–04:00 (marginal, 2.75 h)	42.9° 00:45	11.44	97%	34.9°
2038-12-10 Fri	12	—	unknown	—	42.9° 00:40	11.45	99%	29.4°
2038-12-11 Sat	9	—	unknown	—	42.9° 00:35	11.46	100%	27.9°
2038-12-12 Sun	11	—	unknown	—	42.9° 00:30	11.47	99%	30.9°
2038-12-13 Mon	19	—	unknown	21:20–00:05 (marginal, 2.75 h)	42.9° 00:25	11.48	96%	37.6°
2038-12-14 Tue	31	—	unknown	20:50–03:20 (marginal, 6.5 h)	42.9° 00:25	11.49	90%	46.5°
2038-12-15 Wed	48	—	unknown	20:35–03:40 (marginal, 7.08 h)	42.9° 00:20	11.49	84%	56.7°
2038-12-16 Thu	76	—	unknown	21:00–00:55 (good, 3.92 h)	42.9° 00:15	11.5	75%	67.6°
2038-12-17 Fri	85	—	unknown	21:00–02:55 (good, 5.92 h)	42.9° 00:10	11.5	66%	79.1°
2038-12-18 Sat	88	—	unknown	20:55–03:10 (good, 6.25 h)	42.9° 00:10	11.5	55%	90.9°
2038-12-19 Sun	89	—	unknown	20:50–03:15 (good, 6.42 h)	42.9° 00:05	11.51	44%	103.0°
2038-12-20 Mon	89	—	unknown	20:45–03:15 (good, 6.5 h)	42.9° 00:00	11.51	33%	115.2°
2038-12-21 Tue	89	—	unknown	20:40–03:15 (good, 6.58 h)	42.9° 23:55	11.51	23%	127.3°
2038-12-22 Wed	89	—	unknown	20:40–03:10 (good, 6.5 h)	42.9° 23:50	11.51	14%	138.5°
2038-12-23 Thu	89	—	unknown	20:35–03:05 (good, 6.5 h)	42.9° 23:50	11.51	6%	147.6°
2038-12-24 Fri	89	—	unknown	20:30–03:05 (good, 6.58 h)	42.9° 23:45	11.5	2%	152.1°
2038-12-25 Sat	89	—	unknown	20:25–03:00 (good, 6.58 h)	42.9° 23:40	11.5	0%	149.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-11-26&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.