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: 02-02 (100), 02-03 (100), 02-04 (100), 02-05 (100), 02-06 (100) — by astronomy; check the weather when the night is within four days.

2037-01-31astronomy score per night — click a bar for that night2037-03-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2037-02-14 Sat	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.27	0%	96.1°
2037-02-15 Sun	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:25	10.23	0%	84.4°
2037-02-16 Mon	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:20	10.19	3%	72.8°
2037-02-17 Tue	100	—	unknown	19:35–23:30 (good, 3.92 h)	72.5° 18:20	10.15	7%	61.1°
2037-02-18 Wed	93	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:15	10.11	12%	49.4°
2037-02-19 Thu	84	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:10	10.07	19%	37.7°
2037-02-20 Fri	70	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:05	10.03	27%	26.1°
2037-02-21 Sat	56	—	unknown	19:35–22:55 (good, 3.33 h)	72.5° 18:00	9.98	36%	15.1°
2037-02-22 Sun	43	—	unknown	19:40–22:20 (good, 2.67 h)	72.5° 18:00	9.94	46%	9.0°
2037-02-23 Mon	31	—	unknown	19:40–23:25 (marginal, 3.75 h)	72.5° 17:55	9.9	57%	16.2°
2037-02-24 Tue	21	—	unknown	19:40–23:10 (marginal, 3.5 h)	72.5° 17:50	9.86	68%	28.4°
2037-02-25 Wed	19	—	unknown	19:40–22:55 (marginal, 3.25 h)	72.5° 17:45	9.81	78%	41.8°
2037-02-26 Thu	21	—	unknown	19:45–22:55 (marginal, 3.17 h)	72.5° 17:40	9.77	86%	55.9°
2037-02-27 Fri	26	—	unknown	19:45–22:55 (marginal, 3.17 h)	72.5° 17:40	9.72	94%	70.5°
2037-02-28 Sat	35	—	unknown	19:45–20:50 (good, 1.08 h)	72.5° 17:35	9.68	98%	85.5°
2037-03-01 Sun	47	—	unknown	19:45–22:10 (good, 2.42 h)	72.5° 17:30	9.63	100%	100.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-01-31&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.