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: 11-29 (100), 11-30 (100), 12-01 (100), 12-02 (100), 12-03 (100) — by astronomy; check the weather when the night is within four days.

2026-11-21astronomy score per night — click a bar for that night2026-12-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-11-21 Sat	82	—	unknown	04:30–05:15 (good, 0.75 h)	72.5° 00:05	11.12	90%	36.8°
2026-11-22 Sun	38	—	unknown	00:25–05:25 (marginal, 5.0 h)	72.5° 00:00	11.14	96%	22.5°
2026-11-23 Mon	26	—	unknown	02:35–05:00 (marginal, 2.42 h)	72.5° 00:00	11.17	99%	7.9°
2026-11-24 Tue	24	—	unknown	19:00–20:40 (marginal, 1.67 h)	72.5° 23:55	11.19	100%	7.1°
2026-11-25 Wed	31	—	unknown	18:40–22:40 (marginal, 4.0 h)	72.5° 23:50	11.21	97%	22.1°
2026-11-26 Thu	50	—	unknown	18:35–02:45 (marginal, 8.17 h)	72.5° 23:45	11.23	92%	37.2°
2026-11-27 Fri	86	—	unknown	18:35–22:40 (good, 4.08 h)	72.5° 23:40	11.26	84%	52.1°
2026-11-28 Sat	96	—	unknown	18:35–02:25 (good, 7.83 h)	72.5° 23:40	11.28	75%	66.7°
2026-11-29 Sun	100	—	unknown	18:35–04:10 (good, 9.58 h)	72.5° 23:35	11.3	65%	81.0°
2026-11-30 Mon	100	—	unknown	18:35–04:25 (good, 9.83 h)	72.5° 23:30	11.31	54%	94.9°
2026-12-01 Tue	100	—	unknown	18:35–04:30 (good, 9.92 h)	72.5° 23:25	11.33	43%	108.4°
2026-12-02 Wed	100	—	unknown	18:35–04:30 (good, 9.92 h)	72.5° 23:20	11.35	33%	121.5°
2026-12-03 Thu	100	—	unknown	18:35–04:25 (good, 9.83 h)	72.5° 23:20	11.36	23%	134.4°
2026-12-04 Fri	100	—	unknown	18:35–04:25 (good, 9.83 h)	72.5° 23:15	11.38	16%	147.0°
2026-12-05 Sat	100	—	unknown	18:35–04:20 (good, 9.75 h)	72.5° 23:10	11.39	9%	159.4°
2026-12-06 Sun	100	—	unknown	18:35–04:15 (good, 9.67 h)	72.5° 23:05	11.41	4%	171.6°
2026-12-07 Mon	100	—	unknown	18:35–04:15 (good, 9.67 h)	72.5° 23:00	11.42	1%	176.1°
2026-12-08 Tue	100	—	unknown	18:35–04:10 (good, 9.58 h)	72.5° 23:00	11.43	0%	164.2°
2026-12-09 Wed	100	—	unknown	18:35–04:05 (good, 9.5 h)	72.5° 22:55	11.44	1%	152.3°
2026-12-10 Thu	100	—	unknown	18:35–04:00 (good, 9.42 h)	72.5° 22:50	11.45	3%	140.4°
2026-12-11 Fri	100	—	unknown	18:35–04:00 (good, 9.42 h)	72.5° 22:45	11.46	7%	128.6°
2026-12-12 Sat	100	—	unknown	18:35–03:55 (good, 9.33 h)	72.5° 22:45	11.47	13%	116.8°
2026-12-13 Sun	100	—	unknown	18:35–03:50 (good, 9.25 h)	72.5° 22:40	11.48	20%	104.9°
2026-12-14 Mon	100	—	unknown	18:35–03:45 (good, 9.17 h)	72.5° 22:35	11.49	28%	92.9°
2026-12-15 Tue	100	—	unknown	18:35–03:40 (good, 9.08 h)	72.5° 22:30	11.49	37%	80.7°
2026-12-16 Wed	100	—	unknown	18:35–03:40 (good, 9.08 h)	72.5° 22:25	11.5	47%	68.3°
2026-12-17 Thu	95	—	unknown	18:45–03:35 (good, 8.83 h)	72.5° 22:25	11.5	57%	55.5°
2026-12-18 Fri	86	—	unknown	22:10–03:30 (good, 5.33 h)	72.5° 22:20	11.5	67%	42.3°
2026-12-19 Sat	63	—	unknown	03:20–03:25 (good, 0.08 h)	72.5° 22:15	11.51	77%	28.7°
2026-12-20 Sun	40	—	unknown	18:35–03:35 (marginal, 9.0 h)	72.5° 22:10	11.51	86%	14.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-11-21&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.