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: 01-08 (100), 01-09 (100), 01-10 (100), 01-11 (100), 01-12 (100) — by astronomy; check the weather when the night is within four days.

2041-12-30astronomy score per night — click a bar for that night2042-01-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-12-30 Mon	87	—	unknown	19:10–02:40 (good, 7.5 h)	72.5° 21:30	11.47	59%	40.4°
2041-12-31 Tue	61	—	unknown	02:35–02:40 (good, 0.08 h)	72.5° 21:30	11.46	70%	26.5°
2042-01-01 Wed	43	—	unknown	18:45–02:50 (marginal, 8.08 h)	72.5° 21:25	11.45	79%	12.8°
2042-01-02 Thu	28	—	unknown	18:45–02:30 (marginal, 7.75 h)	72.5° 21:20	11.44	87%	2.1°
2042-01-03 Fri	21	—	unknown	18:45–20:15 (marginal, 1.5 h)	72.5° 21:15	11.43	94%	14.5°
2042-01-04 Sat	20	—	unknown	18:45–20:15 (marginal, 1.5 h)	72.5° 21:10	11.41	98%	27.6°
2042-01-05 Sun	31	—	unknown	18:45–22:55 (marginal, 4.17 h)	72.5° 21:10	11.4	100%	40.6°
2042-01-06 Mon	50	—	unknown	18:50–01:50 (marginal, 7.0 h)	72.5° 21:05	11.39	100%	53.4°
2042-01-07 Tue	69	—	unknown	18:50–21:10 (good, 2.33 h)	72.5° 21:00	11.37	97%	66.0°
2042-01-08 Wed	100	—	unknown	18:50–23:40 (good, 4.83 h)	72.5° 20:55	11.36	93%	78.3°
2042-01-09 Thu	100	—	unknown	18:50–01:05 (good, 6.25 h)	72.5° 20:50	11.34	88%	90.4°
2042-01-10 Fri	100	—	unknown	18:50–01:40 (good, 6.83 h)	72.5° 20:50	11.32	81%	102.4°
2042-01-11 Sat	100	—	unknown	18:50–01:45 (good, 6.92 h)	72.5° 20:45	11.3	73%	114.3°
2042-01-12 Sun	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.5° 20:40	11.28	64%	126.1°
2042-01-13 Mon	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.5° 20:35	11.26	55%	137.9°
2042-01-14 Tue	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.5° 20:35	11.24	46%	149.9°
2042-01-15 Wed	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.5° 20:30	11.22	36%	162.1°
2042-01-16 Thu	100	—	unknown	18:55–01:35 (good, 6.67 h)	72.5° 20:25	11.2	27%	174.4°
2042-01-17 Fri	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:20	11.18	18%	172.3°
2042-01-18 Sat	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:15	11.15	11%	159.1°
2042-01-19 Sun	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.13	5%	145.4°
2042-01-20 Mon	100	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.1	1%	131.3°
2042-01-21 Tue	100	—	unknown	19:00–01:15 (good, 6.25 h)	72.5° 20:05	11.08	0%	116.9°
2042-01-22 Wed	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 20:00	11.05	2%	102.2°
2042-01-23 Thu	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 19:55	11.03	6%	87.5°
2042-01-24 Fri	100	—	unknown	19:05–01:05 (good, 6.0 h)	72.5° 19:55	11.0	13%	72.7°
2042-01-25 Sat	99	—	unknown	19:05–01:00 (good, 5.92 h)	72.5° 19:50	10.97	22%	58.1°
2042-01-26 Sun	90	—	unknown	19:10–00:55 (good, 5.75 h)	72.5° 19:45	10.94	32%	43.7°
2042-01-27 Mon	78	—	unknown	19:10–00:50 (good, 5.67 h)	72.5° 19:40	10.91	43%	29.5°
2042-01-28 Tue	60	—	unknown	20:05–23:45 (good, 3.67 h)	72.5° 19:35	10.88	55%	15.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-12-30&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.