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: 01-18 (100), 01-31 (100), 02-01 (100), 02-02 (100), 02-03 (100) — by astronomy; check the weather when the night is within four days.

2029-01-18astronomy score per night — click a bar for that night2029-02-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-01-18 Thu	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.15	17%	72.5°
2029-01-19 Fri	99	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.13	24%	60.6°
2029-01-20 Sat	92	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.1	33%	48.8°
2029-01-21 Sun	84	—	unknown	19:05–01:15 (good, 6.17 h)	72.5° 20:05	11.08	42%	37.0°
2029-01-22 Mon	68	—	unknown	19:05–00:45 (good, 5.67 h)	72.5° 20:00	11.05	51%	25.1°
2029-01-23 Tue	54	—	unknown	19:05–01:30 (marginal, 6.42 h)	72.5° 19:55	11.02	61%	13.0°
2029-01-24 Wed	37	—	unknown	19:05–01:20 (marginal, 6.25 h)	72.5° 19:50	10.99	70%	0.8°
2029-01-25 Thu	25	—	unknown	19:05–01:00 (marginal, 5.92 h)	72.5° 19:50	10.96	79%	12.0°
2029-01-26 Fri	18	—	unknown	19:10–00:30 (marginal, 5.33 h)	72.5° 19:45	10.94	87%	25.0°
2029-01-27 Sat	21	—	unknown	19:10–22:55 (marginal, 3.75 h)	72.5° 19:40	10.91	93%	38.5°
2029-01-28 Sun	32	—	unknown	19:10–00:30 (marginal, 5.33 h)	72.5° 19:35	10.88	98%	52.4°
2029-01-29 Mon	48	—	unknown	19:10–19:45 (good, 0.58 h)	72.5° 19:30	10.84	100%	66.6°
2029-01-30 Tue	70	—	unknown	19:10–22:15 (good, 3.08 h)	72.5° 19:30	10.81	99%	81.1°
2029-01-31 Wed	100	—	unknown	19:15–23:50 (good, 4.58 h)	72.5° 19:25	10.78	96%	95.8°
2029-02-01 Thu	100	—	unknown	19:15–00:15 (good, 5.0 h)	72.5° 19:20	10.75	90%	110.6°
2029-02-02 Fri	100	—	unknown	19:15–00:20 (good, 5.08 h)	72.5° 19:15	10.71	82%	125.3°
2029-02-03 Sat	100	—	unknown	19:15–00:15 (good, 5.0 h)	72.5° 19:15	10.68	72%	139.8°
2029-02-04 Sun	100	—	unknown	19:20–00:20 (good, 5.0 h)	72.5° 19:10	10.65	61%	154.0°
2029-02-05 Mon	100	—	unknown	19:20–00:15 (good, 4.92 h)	72.5° 19:05	10.61	50%	168.1°
2029-02-06 Tue	100	—	unknown	19:20–00:10 (good, 4.83 h)	72.5° 19:00	10.58	39%	178.1°
2029-02-07 Wed	100	—	unknown	19:20–00:10 (good, 4.83 h)	72.5° 18:55	10.54	28%	164.7°
2029-02-08 Thu	100	—	unknown	19:20–00:05 (good, 4.75 h)	72.5° 18:55	10.5	19%	151.5°
2029-02-09 Fri	100	—	unknown	19:25–00:00 (good, 4.58 h)	72.5° 18:50	10.47	12%	138.5°
2029-02-10 Sat	100	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:45	10.43	6%	125.7°
2029-02-11 Sun	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:40	10.39	2%	113.1°
2029-02-12 Mon	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:35	10.35	0%	100.6°
2029-02-13 Tue	100	—	unknown	19:30–23:45 (good, 4.25 h)	72.5° 18:35	10.31	0%	88.4°
2029-02-14 Wed	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.27	2%	76.3°
2029-02-15 Thu	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:25	10.23	6%	64.3°
2029-02-16 Fri	96	—	unknown	19:30–23:30 (good, 4.0 h)	72.5° 18:20	10.19	11%	52.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-01-18&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.