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: 02-09 (100), 02-10 (100), 02-11 (100), 02-12 (100), 02-13 (100) — by astronomy; check the weather when the night is within four days.

2031-01-29astronomy score per night — click a bar for that night2031-02-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-01-29 Wed	71	—	unknown	19:10–00:25 (good, 5.25 h)	72.5° 19:35	10.86	46%	24.2°
2031-01-30 Thu	55	—	unknown	20:55–22:35 (good, 1.67 h)	72.5° 19:30	10.83	56%	12.3°
2031-01-31 Fri	40	—	unknown	19:15–00:55 (marginal, 5.67 h)	72.5° 19:25	10.8	65%	3.6°
2031-02-01 Sat	28	—	unknown	19:15–00:40 (marginal, 5.42 h)	72.5° 19:20	10.76	74%	12.6°
2031-02-02 Sun	20	—	unknown	19:15–00:20 (marginal, 5.08 h)	72.5° 19:20	10.73	82%	24.1°
2031-02-03 Mon	20	—	unknown	19:15–00:05 (marginal, 4.83 h)	72.5° 19:15	10.7	88%	35.9°
2031-02-04 Tue	26	—	unknown	19:15–00:05 (marginal, 4.83 h)	72.5° 19:10	10.66	94%	47.8°
2031-02-05 Wed	35	—	unknown	19:20–00:10 (marginal, 4.83 h)	72.5° 19:05	10.63	97%	59.8°
2031-02-06 Thu	48	—	unknown	19:20–20:35 (good, 1.25 h)	72.5° 19:05	10.59	100%	71.9°
2031-02-07 Fri	63	—	unknown	19:20–22:10 (good, 2.83 h)	72.5° 19:00	10.56	100%	84.3°
2031-02-08 Sat	81	—	unknown	19:20–23:25 (good, 4.08 h)	72.5° 18:55	10.52	98%	96.8°
2031-02-09 Sun	100	—	unknown	19:25–23:45 (good, 4.33 h)	72.5° 18:50	10.48	94%	109.5°
2031-02-10 Mon	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:45	10.45	88%	122.4°
2031-02-11 Tue	100	—	unknown	19:25–23:45 (good, 4.33 h)	72.5° 18:45	10.41	81%	135.6°
2031-02-12 Wed	100	—	unknown	19:25–23:45 (good, 4.33 h)	72.5° 18:40	10.37	72%	148.8°
2031-02-13 Thu	100	—	unknown	19:25–23:45 (good, 4.33 h)	72.5° 18:35	10.33	61%	162.2°
2031-02-14 Fri	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.29	50%	174.8°
2031-02-15 Sat	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:25	10.25	39%	168.9°
2031-02-16 Sun	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:25	10.21	28%	154.9°
2031-02-17 Mon	100	—	unknown	19:30–23:30 (good, 4.0 h)	72.5° 18:20	10.17	18%	140.6°
2031-02-18 Tue	100	—	unknown	19:35–23:25 (good, 3.83 h)	72.5° 18:15	10.13	10%	126.0°
2031-02-19 Wed	100	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:10	10.09	4%	111.4°
2031-02-20 Thu	97	—	unknown	19:35–23:20 (good, 3.75 h)	72.5° 18:10	10.05	1%	96.9°
2031-02-21 Fri	95	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:05	10.01	0%	82.6°
2031-02-22 Sat	93	—	unknown	19:40–23:10 (good, 3.5 h)	72.5° 18:00	9.96	2%	68.6°
2031-02-23 Sun	88	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:55	9.92	7%	54.9°
2031-02-24 Mon	80	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:50	9.88	13%	41.6°
2031-02-25 Tue	69	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:50	9.83	20%	28.8°
2031-02-26 Wed	57	—	unknown	19:40–22:40 (good, 3.0 h)	72.5° 17:45	9.79	29%	16.5°
2031-02-27 Thu	45	—	unknown	19:45–22:30 (good, 2.75 h)	72.5° 17:40	9.75	38%	5.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-01-29&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.