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: 01-02 (89), 01-03 (89), 01-04 (89), 01-17 (89), 01-18 (89) — by astronomy; check the weather when the night is within four days.

2036-01-02astronomy score per night — click a bar for that night2036-01-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2036-01-21 Mon	89	—	unknown	19:00–01:15 (good, 6.25 h)	42.9° 21:55	11.09	34%	141.4°
2036-01-22 Tue	89	—	unknown	19:05–01:10 (good, 6.08 h)	42.9° 21:50	11.07	25%	149.7°
2036-01-23 Wed	89	—	unknown	19:05–01:05 (good, 6.0 h)	42.9° 21:45	11.04	17%	155.1°
2036-01-24 Thu	89	—	unknown	19:05–01:00 (good, 5.92 h)	42.9° 21:45	11.01	11%	155.6°
2036-01-25 Fri	89	—	unknown	19:05–01:00 (good, 5.92 h)	42.9° 21:40	10.98	6%	151.1°
2036-01-26 Sat	89	—	unknown	19:05–00:55 (good, 5.83 h)	42.9° 21:35	10.96	2%	143.4°
2036-01-27 Sun	89	—	unknown	19:10–00:50 (good, 5.67 h)	42.9° 21:30	10.93	0%	134.2°
2036-01-28 Mon	89	—	unknown	19:10–00:45 (good, 5.58 h)	42.9° 21:25	10.9	0%	124.0°
2036-01-29 Tue	89	—	unknown	19:10–00:45 (good, 5.58 h)	42.9° 21:25	10.87	2%	113.4°
2036-01-30 Wed	89	—	unknown	19:10–00:40 (good, 5.5 h)	42.9° 21:20	10.84	6%	102.5°
2036-01-31 Thu	89	—	unknown	19:15–00:35 (good, 5.33 h)	42.9° 21:15	10.8	11%	91.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-01-02&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.