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: 12-13 (89), 12-14 (89), 12-15 (89), 12-16 (89), 12-17 (89) — by astronomy; check the weather when the night is within four days.

2033-12-04astronomy score per night — click a bar for that night2034-01-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-12-04 Sun	22	—	unknown	00:45–04:25 (marginal, 3.67 h)	42.9° 01:00	11.38	97%	37.3°
2033-12-05 Mon	12	—	unknown	—	42.9° 01:00	11.4	100%	27.8°
2033-12-06 Tue	10	—	unknown	—	42.9° 00:55	11.41	99%	23.8°
2033-12-07 Wed	14	—	unknown	—	42.9° 00:50	11.42	96%	27.5°
2033-12-08 Thu	24	—	unknown	21:25–02:10 (marginal, 4.75 h)	42.9° 00:45	11.44	91%	36.1°
2033-12-09 Fri	41	—	unknown	21:00–03:55 (marginal, 6.92 h)	42.9° 00:40	11.45	84%	46.8°
2033-12-10 Sat	68	—	unknown	21:55–23:45 (good, 1.83 h)	42.9° 00:40	11.46	76%	58.0°
2033-12-11 Sun	84	—	unknown	21:20–02:35 (good, 5.25 h)	42.9° 00:35	11.47	66%	69.2°
2033-12-12 Mon	88	—	unknown	21:15–03:25 (good, 6.17 h)	42.9° 00:30	11.47	57%	80.4°
2033-12-13 Tue	89	—	unknown	21:10–03:30 (good, 6.33 h)	42.9° 00:25	11.48	47%	91.5°
2033-12-14 Wed	89	—	unknown	21:10–03:35 (good, 6.42 h)	42.9° 00:20	11.49	38%	102.3°
2033-12-15 Thu	89	—	unknown	21:05–03:35 (good, 6.5 h)	42.9° 00:20	11.49	29%	113.0°
2033-12-16 Fri	89	—	unknown	21:00–03:30 (good, 6.5 h)	42.9° 00:15	11.5	21%	123.6°
2033-12-17 Sat	89	—	unknown	20:55–03:30 (good, 6.58 h)	42.9° 00:10	11.5	14%	133.7°
2033-12-18 Sun	89	—	unknown	20:55–03:25 (good, 6.5 h)	42.9° 00:05	11.5	8%	143.2°
2033-12-19 Mon	89	—	unknown	20:50–03:20 (good, 6.5 h)	42.9° 00:05	11.51	4%	151.2°
2033-12-20 Tue	89	—	unknown	20:45–03:20 (good, 6.58 h)	42.9° 00:00	11.51	1%	155.8°
2033-12-21 Wed	89	—	unknown	20:40–03:15 (good, 6.58 h)	42.9° 23:55	11.51	0%	154.8°
2033-12-22 Thu	89	—	unknown	20:35–03:10 (good, 6.58 h)	42.9° 23:50	11.51	2%	148.4°
2033-12-23 Fri	89	—	unknown	20:35–03:05 (good, 6.5 h)	42.9° 23:45	11.5	5%	138.9°
2033-12-24 Sat	89	—	unknown	20:30–03:00 (good, 6.5 h)	42.9° 23:45	11.5	11%	127.9°
2033-12-25 Sun	89	—	unknown	20:25–03:00 (good, 6.58 h)	42.9° 23:40	11.5	18%	116.0°
2033-12-26 Mon	89	—	unknown	20:25–02:55 (good, 6.5 h)	42.9° 23:35	11.49	28%	103.7°
2033-12-27 Tue	89	—	unknown	20:30–02:50 (good, 6.33 h)	42.9° 23:30	11.49	38%	91.1°
2033-12-28 Wed	88	—	unknown	20:35–02:45 (good, 6.17 h)	42.9° 23:25	11.48	49%	78.3°
2033-12-29 Thu	83	—	unknown	21:20–02:45 (good, 5.42 h)	42.9° 23:25	11.48	60%	65.5°
2033-12-30 Fri	60	—	unknown	00:50–02:05 (good, 1.25 h)	42.9° 23:20	11.47	71%	52.9°
2033-12-31 Sat	38	—	unknown	20:10–03:00 (marginal, 6.83 h)	42.9° 23:15	11.46	81%	41.0°
2034-01-01 Sun	21	—	unknown	22:55–02:30 (marginal, 3.58 h)	42.9° 23:10	11.45	89%	30.8°
2034-01-02 Mon	13	—	unknown	—	42.9° 23:10	11.44	95%	24.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-12-04&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.