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: 12-22 (89), 12-23 (89), 12-24 (89), 12-25 (89), 12-26 (89) — by astronomy; check the weather when the night is within four days.

2035-12-22astronomy score per night — click a bar for that night2036-01-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-12-22 Sat	89	—	unknown	20:40–03:05 (good, 6.42 h)	42.9° 23:55	11.51	37%	111.9°
2035-12-23 Sun	89	—	unknown	20:35–03:05 (good, 6.5 h)	42.9° 23:50	11.51	28%	123.2°
2035-12-24 Mon	89	—	unknown	20:30–03:05 (good, 6.58 h)	42.9° 23:45	11.5	19%	133.8°
2035-12-25 Tue	89	—	unknown	20:25–03:00 (good, 6.58 h)	42.9° 23:40	11.5	12%	143.5°
2035-12-26 Wed	89	—	unknown	20:25–02:55 (good, 6.5 h)	42.9° 23:35	11.5	7%	151.2°
2035-12-27 Thu	89	—	unknown	20:20–02:50 (good, 6.5 h)	42.9° 23:35	11.49	3%	155.6°
2035-12-28 Fri	89	—	unknown	20:15–02:50 (good, 6.58 h)	42.9° 23:30	11.49	0%	154.8°
2035-12-29 Sat	89	—	unknown	20:10–02:45 (good, 6.58 h)	42.9° 23:25	11.48	0%	149.4°
2035-12-30 Sun	89	—	unknown	20:05–02:40 (good, 6.58 h)	42.9° 23:20	11.47	2%	141.2°
2035-12-31 Mon	89	—	unknown	20:05–02:35 (good, 6.5 h)	42.9° 23:20	11.46	5%	131.7°
2036-01-01 Tue	89	—	unknown	20:00–02:35 (good, 6.58 h)	42.9° 23:15	11.45	10%	121.5°
2036-01-02 Wed	89	—	unknown	20:00–02:30 (good, 6.5 h)	42.9° 23:10	11.44	16%	110.9°
2036-01-03 Thu	89	—	unknown	19:55–02:25 (good, 6.5 h)	42.9° 23:05	11.43	23%	99.9°
2036-01-04 Fri	89	—	unknown	19:55–02:20 (good, 6.42 h)	42.9° 23:00	11.42	32%	88.8°
2036-01-05 Sat	88	—	unknown	20:00–02:15 (good, 6.25 h)	42.9° 23:00	11.41	42%	77.4°
2036-01-06 Sun	85	—	unknown	20:10–02:15 (good, 6.08 h)	42.9° 22:55	11.39	52%	65.8°
2036-01-07 Mon	73	—	unknown	22:10–02:10 (good, 4.0 h)	42.9° 22:50	11.38	62%	54.1°
2036-01-08 Tue	47	—	unknown	19:30–02:35 (marginal, 7.08 h)	42.9° 22:45	11.36	73%	42.6°
2036-01-09 Wed	28	—	unknown	19:55–02:15 (marginal, 6.33 h)	42.9° 22:40	11.35	82%	32.2°
2036-01-10 Thu	17	—	unknown	00:00–01:40 (marginal, 1.67 h)	42.9° 22:40	11.33	90%	25.1°
2036-01-11 Fri	12	—	unknown	—	42.9° 22:35	11.31	96%	25.1°
2036-01-12 Sat	14	—	unknown	19:40–20:15 (marginal, 0.58 h)	42.9° 22:30	11.29	100%	32.6°
2036-01-13 Sun	25	—	unknown	19:00–23:40 (marginal, 4.67 h)	42.9° 22:25	11.28	100%	44.0°
2036-01-14 Mon	42	—	unknown	18:55–01:30 (marginal, 6.58 h)	42.9° 22:25	11.26	97%	56.8°
2036-01-15 Tue	82	—	unknown	19:05–22:10 (good, 3.08 h)	42.9° 22:20	11.23	91%	70.2°
2036-01-16 Wed	87	—	unknown	19:00–00:30 (good, 5.5 h)	42.9° 22:15	11.21	83%	83.4°
2036-01-17 Thu	89	—	unknown	19:00–01:10 (good, 6.17 h)	42.9° 22:10	11.19	74%	96.3°
2036-01-18 Fri	89	—	unknown	19:00–01:15 (good, 6.25 h)	42.9° 22:05	11.17	64%	108.6°
2036-01-19 Sat	89	—	unknown	19:00–01:15 (good, 6.25 h)	42.9° 22:05	11.14	54%	120.4°
2036-01-20 Sun	89	—	unknown	19:00–01:20 (good, 6.33 h)	42.9° 22:00	11.12	43%	131.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-12-22&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.