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: 01-04 (100), 01-05 (100), 01-06 (100), 01-07 (100), 01-08 (100) — by astronomy; check the weather when the night is within four days.

2043-01-04astronomy score per night — click a bar for that night2043-02-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-01-04 Sun	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.5° 21:15	11.42	34%	152.7°
2043-01-05 Mon	100	—	unknown	18:45–02:20 (good, 7.58 h)	72.6° 21:10	11.4	26%	164.6°
2043-01-06 Tue	100	—	unknown	18:50–02:15 (good, 7.42 h)	72.6° 21:05	11.39	18%	176.5°
2043-01-07 Wed	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.6° 21:00	11.38	11%	171.3°
2043-01-08 Thu	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.5° 20:55	11.36	6%	159.0°
2043-01-09 Fri	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:55	11.34	2%	146.4°
2043-01-10 Sat	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.6° 20:50	11.33	0%	133.6°
2043-01-11 Sun	100	—	unknown	18:50–01:55 (good, 7.08 h)	72.6° 20:45	11.31	1%	120.4°
2043-01-12 Mon	100	—	unknown	18:55–01:50 (good, 6.92 h)	72.5° 20:40	11.29	3%	107.1°
2043-01-13 Tue	100	—	unknown	18:55–01:50 (good, 6.92 h)	72.5° 20:35	11.27	8%	93.5°
2043-01-14 Wed	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.5° 20:35	11.25	15%	79.8°
2043-01-15 Thu	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.6° 20:30	11.23	24%	65.9°
2043-01-16 Fri	95	—	unknown	18:55–01:35 (good, 6.67 h)	72.6° 20:25	11.21	34%	52.0°
2043-01-17 Sat	85	—	unknown	19:00–01:35 (good, 6.58 h)	72.5° 20:20	11.18	45%	37.9°
2043-01-18 Sun	64	—	unknown	20:45–01:00 (good, 4.25 h)	72.5° 20:20	11.16	56%	23.8°
2043-01-19 Mon	47	—	unknown	19:00–01:45 (marginal, 6.75 h)	72.6° 20:15	11.14	67%	9.6°
2043-01-20 Tue	30	—	unknown	19:00–01:30 (marginal, 6.5 h)	72.6° 20:10	11.11	78%	4.6°
2043-01-21 Wed	20	—	unknown	19:00–01:00 (marginal, 6.0 h)	72.6° 20:05	11.09	86%	18.7°
2043-01-22 Thu	18	—	unknown	19:05–20:55 (marginal, 1.83 h)	72.5° 20:00	11.06	93%	32.8°
2043-01-23 Fri	28	—	unknown	19:05–23:50 (marginal, 4.75 h)	72.5° 20:00	11.03	98%	46.7°
2043-01-24 Sat	44	—	unknown	19:05–00:55 (marginal, 5.83 h)	72.6° 19:55	11.0	100%	60.5°
2043-01-25 Sun	64	—	unknown	19:05–21:35 (good, 2.5 h)	72.6° 19:50	10.98	99%	73.9°
2043-01-26 Mon	80	—	unknown	19:05–23:15 (good, 4.17 h)	72.5° 19:45	10.95	97%	87.1°
2043-01-27 Tue	100	—	unknown	19:10–00:30 (good, 5.33 h)	72.5° 19:40	10.92	92%	100.0°
2043-01-28 Wed	100	—	unknown	19:10–00:35 (good, 5.42 h)	72.5° 19:40	10.89	86%	112.5°
2043-01-29 Thu	100	—	unknown	19:10–00:35 (good, 5.42 h)	72.6° 19:35	10.86	79%	124.8°
2043-01-30 Fri	100	—	unknown	19:10–00:35 (good, 5.42 h)	72.6° 19:30	10.83	70%	136.9°
2043-01-31 Sat	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.5° 19:25	10.79	62%	148.8°
2043-02-01 Sun	100	—	unknown	19:15–00:35 (good, 5.33 h)	72.5° 19:25	10.76	52%	160.6°
2043-02-02 Mon	100	—	unknown	19:15–00:30 (good, 5.25 h)	72.6° 19:20	10.73	43%	172.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-01-04&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.