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: 02-19 (100), 02-20 (97), 02-21 (95), 02-22 (93), 02-23 (88) — by astronomy; check the weather when the night is within four days.

2031-02-19astronomy score per night — click a bar for that night2031-03-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2031-02-28 Fri	35	—	unknown	19:45–21:00 (good, 1.25 h)	72.5° 17:35	9.7	48%	9.1°
2031-03-01 Sat	25	—	unknown	19:45–23:00 (marginal, 3.25 h)	72.5° 17:30	9.66	57%	20.5°
2031-03-02 Sun	19	—	unknown	19:45–22:45 (marginal, 3.0 h)	72.5° 17:30	9.61	66%	32.2°
2031-03-03 Mon	18	—	unknown	19:50–22:40 (marginal, 2.83 h)	72.5° 17:25	9.56	75%	44.0°
2031-03-04 Tue	19	—	unknown	19:50–22:35 (marginal, 2.75 h)	72.5° 17:20	9.52	83%	55.9°
2031-03-05 Wed	22	—	unknown	19:50–22:35 (marginal, 2.75 h)	72.5° 17:15	9.47	89%	68.0°
2031-03-06 Thu	27	—	unknown	19:50–20:10 (good, 0.33 h)	72.5° 17:15	9.42	95%	80.3°
2031-03-07 Fri	32	—	unknown	19:55–21:15 (good, 1.33 h)	72.5° 17:10	9.38	98%	92.8°
2031-03-08 Sat	40	—	unknown	19:55–21:55 (good, 2.0 h)	72.5° 17:05	9.33	100%	105.7°
2031-03-09 Sun	46	—	unknown	19:55–22:00 (good, 2.08 h)	72.5° 17:00	9.28	99%	118.7°
2031-03-10 Mon	52	—	unknown	19:55–22:00 (good, 2.08 h)	72.5° 16:55	9.23	96%	132.0°
2031-03-11 Tue	51	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:55	9.18	91%	145.5°
2031-03-12 Wed	50	—	unknown	20:00–22:00 (good, 2.0 h)	72.5° 16:50	9.14	84%	159.1°
2031-03-13 Thu	49	—	unknown	20:00–21:55 (good, 1.92 h)	72.5° 16:45	9.09	75%	172.2°
2031-03-14 Fri	47	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:40	9.04	65%	171.7°
2031-03-15 Sat	44	—	unknown	20:05–21:50 (good, 1.75 h)	72.5° 16:35	8.99	54%	158.3°
2031-03-16 Sun	42	—	unknown	20:05–21:45 (good, 1.67 h)	72.5° 16:35	8.94	42%	144.3°
2031-03-17 Mon	41	—	unknown	20:05–21:40 (good, 1.58 h)	72.5° 16:30	8.89	31%	130.2°
2031-03-18 Tue	39	—	unknown	20:05–21:35 (good, 1.5 h)	72.5° 16:25	8.84	21%	116.0°
2031-03-19 Wed	37	—	unknown	20:05–21:30 (good, 1.42 h)	72.5° 16:20	8.78	13%	101.9°
2031-03-20 Thu	34	—	unknown	20:10–21:30 (good, 1.33 h)	72.5° 16:20	8.73	6%	87.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-02-19&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.