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: 12-20 (100), 12-21 (100), 12-22 (100), 12-23 (100), 12-24 (100) — by astronomy; check the weather when the night is within four days.

2035-12-20astronomy score per night — click a bar for that night2036-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-12-20 Thu	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.5° 22:15	11.51	58%	109.5°
2035-12-21 Fri	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.5° 22:10	11.51	47%	122.7°
2035-12-22 Sat	100	—	unknown	18:35–03:10 (good, 8.58 h)	72.5° 22:05	11.51	37%	135.5°
2035-12-23 Sun	100	—	unknown	18:40–03:10 (good, 8.5 h)	72.5° 22:00	11.51	28%	147.8°
2035-12-24 Mon	100	—	unknown	18:40–03:10 (good, 8.5 h)	72.5° 21:55	11.5	19%	159.4°
2035-12-25 Tue	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.5° 21:55	11.5	12%	168.9°
2035-12-26 Wed	100	—	unknown	18:40–03:00 (good, 8.33 h)	72.5° 21:50	11.5	7%	169.1°
2035-12-27 Thu	100	—	unknown	18:40–02:55 (good, 8.25 h)	72.5° 21:45	11.49	3%	159.9°
2035-12-28 Fri	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.5° 21:40	11.49	0%	148.9°
2035-12-29 Sat	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.5° 21:35	11.48	0%	137.5°
2035-12-30 Sun	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.5° 21:35	11.47	2%	126.0°
2035-12-31 Mon	100	—	unknown	18:45–02:40 (good, 7.92 h)	72.5° 21:30	11.46	5%	114.3°
2036-01-01 Tue	100	—	unknown	18:45–02:35 (good, 7.83 h)	72.5° 21:25	11.45	10%	102.6°
2036-01-02 Wed	100	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:20	11.44	16%	90.9°
2036-01-03 Thu	100	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:20	11.43	23%	79.0°
2036-01-04 Fri	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.5° 21:15	11.42	32%	66.9°
2036-01-05 Sat	96	—	unknown	18:45–02:20 (good, 7.58 h)	72.5° 21:10	11.41	42%	54.6°
2036-01-06 Sun	88	—	unknown	18:45–02:15 (good, 7.5 h)	72.5° 21:05	11.39	52%	42.1°
2036-01-07 Mon	79	—	unknown	22:15–02:15 (good, 4.0 h)	72.5° 21:00	11.38	62%	29.4°
2036-01-08 Tue	51	—	unknown	18:50–02:30 (marginal, 7.67 h)	72.5° 21:00	11.36	73%	17.0°
2036-01-09 Wed	34	—	unknown	18:50–02:15 (marginal, 7.42 h)	72.5° 20:55	11.35	82%	9.3°
2036-01-10 Thu	25	—	unknown	18:50–01:45 (marginal, 6.92 h)	72.5° 20:50	11.33	90%	17.2°
2036-01-11 Fri	22	—	unknown	18:50–20:55 (marginal, 2.08 h)	72.5° 20:45	11.31	96%	30.8°
2036-01-12 Sat	36	—	unknown	18:55–00:25 (marginal, 5.5 h)	72.5° 20:40	11.29	100%	45.5°
2036-01-13 Sun	59	—	unknown	18:55–19:45 (good, 0.83 h)	72.5° 20:40	11.28	100%	60.5°
2036-01-14 Mon	76	—	unknown	18:55–22:55 (good, 4.0 h)	72.5° 20:35	11.26	97%	75.5°
2036-01-15 Tue	100	—	unknown	18:55–00:35 (good, 5.67 h)	72.5° 20:30	11.23	91%	90.3°
2036-01-16 Wed	100	—	unknown	18:55–01:20 (good, 6.42 h)	72.5° 20:25	11.21	83%	104.6°
2036-01-17 Thu	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:25	11.19	74%	118.5°
2036-01-18 Fri	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:20	11.17	64%	131.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-12-20&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.