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 Seven Sisters: 01-15 (100), 01-16 (100), 01-17 (100), 01-18 (100), 01-19 (100) — by astronomy; check the weather when the night is within four days.

2037-01-15astronomy score per night — click a bar for that night2037-02-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-01-15 Thu	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.5° 20:25	11.22	0%	128.5°
2037-01-16 Fri	100	—	unknown	18:55–01:35 (good, 6.67 h)	72.5° 20:25	11.2	0%	116.6°
2037-01-17 Sat	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:20	11.17	2%	104.8°
2037-01-18 Sun	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.15	6%	93.0°
2037-01-19 Mon	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:10	11.12	11%	81.4°
2037-01-20 Tue	100	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.1	17%	69.7°
2037-01-21 Wed	99	—	unknown	19:05–01:15 (good, 6.17 h)	72.5° 20:05	11.07	25%	58.0°
2037-01-22 Thu	91	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 20:00	11.05	34%	46.3°
2037-01-23 Fri	83	—	unknown	19:05–01:05 (good, 6.0 h)	72.5° 19:55	11.02	43%	34.5°
2037-01-24 Sat	67	—	unknown	19:05–00:40 (good, 5.58 h)	72.5° 19:50	10.99	53%	22.8°
2037-01-25 Sun	50	—	unknown	19:05–01:25 (marginal, 6.33 h)	72.5° 19:50	10.96	63%	12.2°
2037-01-26 Mon	34	—	unknown	19:10–01:10 (marginal, 6.0 h)	72.5° 19:45	10.93	73%	10.3°
2037-01-27 Tue	23	—	unknown	19:10–00:45 (marginal, 5.58 h)	72.5° 19:40	10.9	82%	20.6°
2037-01-28 Wed	20	—	unknown	19:10–23:30 (marginal, 4.33 h)	72.5° 19:35	10.87	90%	33.8°
2037-01-29 Thu	27	—	unknown	19:10–00:20 (marginal, 5.17 h)	72.5° 19:30	10.84	96%	48.0°
2037-01-30 Fri	42	—	unknown	19:10–00:30 (marginal, 5.33 h)	72.5° 19:30	10.81	99%	62.7°
2037-01-31 Sat	61	—	unknown	19:15–21:45 (good, 2.5 h)	72.5° 19:25	10.78	100%	77.6°
2037-02-01 Sun	82	—	unknown	19:15–23:25 (good, 4.17 h)	72.5° 19:20	10.75	97%	92.7°
2037-02-02 Mon	100	—	unknown	19:15–00:10 (good, 4.92 h)	72.5° 19:15	10.71	92%	107.6°
2037-02-03 Tue	100	—	unknown	19:15–00:15 (good, 5.0 h)	72.5° 19:15	10.68	84%	122.2°
2037-02-04 Wed	100	—	unknown	19:20–00:15 (good, 4.92 h)	72.5° 19:10	10.64	74%	136.4°
2037-02-05 Thu	100	—	unknown	19:20–00:10 (good, 4.83 h)	72.5° 19:05	10.61	64%	149.9°
2037-02-06 Fri	100	—	unknown	19:20–00:10 (good, 4.83 h)	72.5° 19:00	10.57	53%	162.4°
2037-02-07 Sat	100	—	unknown	19:20–00:10 (good, 4.83 h)	72.5° 18:55	10.54	43%	170.7°
2037-02-08 Sun	100	—	unknown	19:20–00:05 (good, 4.75 h)	72.5° 18:55	10.5	33%	165.9°
2037-02-09 Mon	100	—	unknown	19:25–00:00 (good, 4.58 h)	72.5° 18:50	10.46	24%	155.0°
2037-02-10 Tue	100	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:45	10.43	16%	143.2°
2037-02-11 Wed	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:40	10.39	9%	131.4°
2037-02-12 Thu	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:35	10.35	4%	119.6°
2037-02-13 Fri	100	—	unknown	19:30–23:45 (good, 4.25 h)	72.5° 18:35	10.31	1%	107.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-01-15&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.