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: 12-21 (89), 12-22 (89), 12-23 (89), 12-24 (89), 12-25 (89) — by astronomy; check the weather when the night is within four days.

2035-12-11astronomy score per night — click a bar for that night2036-01-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-12-11 Tue	46	—	unknown	21:25–04:25 (marginal, 7.0 h)	42.9° 00:35	11.46	87%	49.7°
2035-12-12 Wed	26	—	unknown	22:50–04:05 (marginal, 5.25 h)	42.9° 00:30	11.47	93%	38.1°
2035-12-13 Thu	14	—	unknown	02:50–03:20 (marginal, 0.5 h)	42.9° 00:30	11.48	98%	28.5°
2035-12-14 Fri	10	—	unknown	—	42.9° 00:25	11.48	100%	24.1°
2035-12-15 Sat	12	—	unknown	—	42.9° 00:20	11.49	99%	27.9°
2035-12-16 Sun	22	—	unknown	21:00–00:55 (marginal, 3.92 h)	42.9° 00:15	11.5	94%	37.5°
2035-12-17 Mon	40	—	unknown	20:35–03:20 (marginal, 6.75 h)	42.9° 00:15	11.5	88%	49.5°
2035-12-18 Tue	71	—	unknown	21:25–23:35 (good, 2.17 h)	42.9° 00:10	11.5	79%	62.3°
2035-12-19 Wed	85	—	unknown	20:50–02:20 (good, 5.5 h)	42.9° 00:05	11.51	69%	75.2°
2035-12-20 Thu	88	—	unknown	20:45–03:00 (good, 6.25 h)	42.9° 00:00	11.51	58%	87.8°
2035-12-21 Fri	89	—	unknown	20:45–03:05 (good, 6.33 h)	42.9° 23:55	11.51	47%	100.1°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-12-11&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.