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: 02-11 (100), 02-12 (100), 02-13 (100), 02-14 (100), 02-15 (100) — by astronomy; check the weather when the night is within four days.

2039-02-11astronomy score per night — click a bar for that night2039-03-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-02-11 Fri	100	—	unknown	19:25–23:45 (good, 4.33 h)	72.5° 18:45	10.41	91%	118.1°
2039-02-12 Sat	100	—	unknown	19:25–23:40 (good, 4.25 h)	72.5° 18:40	10.37	83%	131.9°
2039-02-13 Sun	100	—	unknown	19:25–23:40 (good, 4.25 h)	72.5° 18:35	10.33	74%	145.8°
2039-02-14 Mon	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.29	63%	159.4°
2039-02-15 Tue	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.25	52%	171.4°
2039-02-16 Wed	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:25	10.21	41%	169.1°
2039-02-17 Thu	100	—	unknown	19:30–23:30 (good, 4.0 h)	72.5° 18:20	10.17	30%	156.3°
2039-02-18 Fri	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:15	10.13	20%	142.7°
2039-02-19 Sat	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:10	10.09	12%	128.9°
2039-02-20 Sun	97	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:10	10.05	6%	115.2°
2039-02-21 Mon	95	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:05	10.01	2%	101.7°
2039-02-22 Tue	93	—	unknown	19:40–23:10 (good, 3.5 h)	72.5° 18:00	9.96	0%	88.4°
2039-02-23 Wed	91	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:55	9.92	1%	75.3°
2039-02-24 Thu	89	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:50	9.88	4%	62.5°
2039-02-25 Fri	83	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:50	9.83	8%	50.1°
2039-02-26 Sat	76	—	unknown	19:40–22:55 (good, 3.25 h)	72.5° 17:45	9.79	14%	37.9°
2039-02-27 Sun	64	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:40	9.74	22%	26.1°
2039-02-28 Mon	53	—	unknown	19:45–22:35 (good, 2.83 h)	72.5° 17:35	9.7	30%	14.9°
2039-03-01 Tue	42	—	unknown	19:45–22:20 (good, 2.58 h)	72.5° 17:35	9.65	39%	6.7°
2039-03-02 Wed	32	—	unknown	19:45–20:40 (good, 0.92 h)	72.5° 17:30	9.61	48%	12.1°
2039-03-03 Thu	23	—	unknown	19:50–22:50 (marginal, 3.0 h)	72.5° 17:25	9.56	58%	23.1°
2039-03-04 Fri	18	—	unknown	19:50–22:40 (marginal, 2.83 h)	72.5° 17:20	9.52	67%	34.8°
2039-03-05 Sat	17	—	unknown	19:50–22:30 (marginal, 2.67 h)	72.5° 17:15	9.47	76%	46.9°
2039-03-06 Sun	18	—	unknown	19:50–22:25 (marginal, 2.58 h)	72.5° 17:15	9.42	84%	59.4°
2039-03-07 Mon	21	—	unknown	19:55–22:30 (marginal, 2.58 h)	72.5° 17:10	9.38	91%	72.3°
2039-03-08 Tue	27	—	unknown	19:55–20:25 (good, 0.5 h)	72.5° 17:05	9.33	96%	85.6°
2039-03-09 Wed	33	—	unknown	19:55–21:35 (good, 1.67 h)	72.5° 17:00	9.28	99%	99.2°
2039-03-10 Thu	41	—	unknown	19:55–21:50 (good, 1.92 h)	72.5° 16:55	9.23	100%	113.2°
2039-03-11 Fri	43	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:55	9.18	98%	127.4°
2039-03-12 Sat	49	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:50	9.13	93%	141.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-02-11&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.