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: 01-25 (100), 01-26 (100), 01-27 (100), 01-28 (100), 01-29 (100) — by astronomy; check the weather when the night is within four days.

2041-01-25astronomy score per night — click a bar for that night2041-02-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-01-25 Fri	100	—	unknown	19:05–01:00 (good, 5.92 h)	72.5° 19:50	10.96	45%	161.8°
2041-01-26 Sat	100	—	unknown	19:10–00:55 (good, 5.75 h)	72.5° 19:45	10.93	34%	174.3°
2041-01-27 Sun	100	—	unknown	19:10–00:50 (good, 5.67 h)	72.5° 19:40	10.9	24%	170.4°
2041-01-28 Mon	100	—	unknown	19:10–00:45 (good, 5.58 h)	72.5° 19:35	10.87	15%	156.5°
2041-01-29 Tue	100	—	unknown	19:10–00:45 (good, 5.58 h)	72.5° 19:35	10.84	8%	142.0°
2041-01-30 Wed	100	—	unknown	19:10–00:40 (good, 5.5 h)	72.5° 19:30	10.81	3%	127.0°
2041-01-31 Thu	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.5° 19:25	10.78	0%	111.8°
2041-02-01 Fri	100	—	unknown	19:15–00:30 (good, 5.25 h)	72.5° 19:20	10.75	1%	96.6°
2041-02-02 Sat	100	—	unknown	19:15–00:30 (good, 5.25 h)	72.5° 19:15	10.71	5%	81.4°
2041-02-03 Sun	100	—	unknown	19:15–00:25 (good, 5.17 h)	72.5° 19:15	10.68	11%	66.5°
2041-02-04 Mon	96	—	unknown	19:20–00:20 (good, 5.0 h)	72.5° 19:10	10.64	19%	52.0°
2041-02-05 Tue	86	—	unknown	19:20–00:15 (good, 4.92 h)	72.5° 19:05	10.61	29%	38.0°
2041-02-06 Wed	75	—	unknown	19:20–23:55 (good, 4.58 h)	72.5° 19:00	10.57	39%	24.4°
2041-02-07 Thu	56	—	unknown	19:20–23:35 (good, 4.25 h)	72.5° 18:55	10.54	50%	11.6°
2041-02-08 Fri	40	—	unknown	19:20–00:25 (marginal, 5.08 h)	72.5° 18:55	10.5	60%	3.7°
2041-02-09 Sat	28	—	unknown	19:25–00:10 (marginal, 4.75 h)	72.5° 18:50	10.46	69%	14.5°
2041-02-10 Sun	19	—	unknown	19:25–23:50 (marginal, 4.42 h)	72.5° 18:45	10.43	78%	26.5°
2041-02-11 Mon	19	—	unknown	19:25–23:35 (marginal, 4.17 h)	72.5° 18:40	10.39	85%	38.5°
2041-02-12 Tue	23	—	unknown	19:25–23:35 (marginal, 4.17 h)	72.5° 18:35	10.35	91%	50.4°
2041-02-13 Wed	29	—	unknown	19:30–23:40 (marginal, 4.17 h)	72.5° 18:35	10.31	96%	62.2°
2041-02-14 Thu	40	—	unknown	19:30–20:20 (good, 0.83 h)	72.5° 18:30	10.27	99%	74.0°
2041-02-15 Fri	51	—	unknown	19:30–21:35 (good, 2.08 h)	72.5° 18:25	10.23	100%	85.8°
2041-02-16 Sat	65	—	unknown	19:30–22:45 (good, 3.25 h)	72.5° 18:20	10.19	99%	97.7°
2041-02-17 Sun	77	—	unknown	19:35–23:10 (good, 3.58 h)	72.5° 18:20	10.15	97%	109.6°
2041-02-18 Mon	93	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:15	10.11	93%	121.6°
2041-02-19 Tue	95	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:10	10.07	87%	133.7°
2041-02-20 Wed	95	—	unknown	19:35–23:10 (good, 3.58 h)	72.5° 18:05	10.03	80%	146.0°
2041-02-21 Thu	94	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:00	9.98	71%	158.5°
2041-02-22 Fri	92	—	unknown	19:40–23:10 (good, 3.5 h)	72.5° 18:00	9.94	61%	171.0°
2041-02-23 Sat	91	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:55	9.9	51%	174.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-01-25&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.