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: 12-17 (100), 12-18 (100), 12-19 (100), 12-20 (100), 12-21 (100) — by astronomy; check the weather when the night is within four days.

2046-12-13astronomy score per night — click a bar for that night2047-01-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-12-13 Thu	28	—	unknown	18:35–21:35 (marginal, 3.0 h)	72.6° 22:40	11.48	100%	28.4°
2046-12-14 Fri	49	—	unknown	18:35–01:20 (marginal, 6.75 h)	72.6° 22:35	11.49	98%	41.5°
2046-12-15 Sat	88	—	unknown	18:35–21:10 (good, 2.58 h)	72.6° 22:30	11.49	93%	54.8°
2046-12-16 Sun	97	—	unknown	18:35–00:35 (good, 6.0 h)	72.6° 22:30	11.5	87%	68.3°
2046-12-17 Mon	100	—	unknown	18:35–02:20 (good, 7.75 h)	72.6° 22:25	11.5	78%	81.9°
2046-12-18 Tue	100	—	unknown	18:35–03:10 (good, 8.58 h)	72.6° 22:20	11.5	69%	95.7°
2046-12-19 Wed	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.6° 22:15	11.51	58%	109.7°
2046-12-20 Thu	100	—	unknown	18:35–03:20 (good, 8.75 h)	72.6° 22:10	11.51	46%	123.8°
2046-12-21 Fri	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.6° 22:10	11.51	35%	137.9°
2046-12-22 Sat	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.6° 22:05	11.51	25%	152.2°
2046-12-23 Sun	100	—	unknown	18:40–03:10 (good, 8.5 h)	72.6° 22:00	11.51	15%	166.5°
2046-12-24 Mon	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.6° 21:55	11.5	8%	179.2°
2046-12-25 Tue	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.6° 21:50	11.5	3%	165.0°
2046-12-26 Wed	100	—	unknown	18:40–03:00 (good, 8.33 h)	72.6° 21:50	11.5	0%	151.0°
2046-12-27 Thu	100	—	unknown	18:40–02:55 (good, 8.25 h)	72.6° 21:45	11.49	0%	137.2°
2046-12-28 Fri	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.6° 21:40	11.48	3%	123.8°
2046-12-29 Sat	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.6° 21:35	11.48	7%	110.7°
2046-12-30 Sun	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.6° 21:35	11.47	13%	97.9°
2046-12-31 Mon	100	—	unknown	18:45–02:40 (good, 7.92 h)	72.6° 21:30	11.46	20%	85.4°
2047-01-01 Tue	100	—	unknown	18:45–02:35 (good, 7.83 h)	72.6° 21:25	11.45	29%	73.2°
2047-01-02 Wed	99	—	unknown	18:45–02:30 (good, 7.75 h)	72.6° 21:20	11.44	38%	61.2°
2047-01-03 Thu	92	—	unknown	18:45–02:30 (good, 7.75 h)	72.6° 21:15	11.43	47%	49.4°
2047-01-04 Fri	84	—	unknown	19:05–02:25 (good, 7.33 h)	72.6° 21:15	11.42	57%	37.5°
2047-01-05 Sat	59	—	unknown	18:45–02:45 (marginal, 8.0 h)	72.6° 21:10	11.4	66%	25.7°
2047-01-06 Sun	46	—	unknown	18:50–02:35 (marginal, 7.75 h)	72.6° 21:05	11.39	75%	13.7°
2047-01-07 Mon	32	—	unknown	18:50–02:20 (marginal, 7.5 h)	72.6° 21:00	11.37	83%	1.5°
2047-01-08 Tue	22	—	unknown	22:05–01:55 (marginal, 3.83 h)	72.6° 20:55	11.36	90%	11.1°
2047-01-09 Wed	20	—	unknown	18:50–20:10 (marginal, 1.33 h)	72.6° 20:55	11.34	95%	23.9°
2047-01-10 Thu	26	—	unknown	18:50–21:50 (marginal, 3.0 h)	72.6° 20:50	11.33	98%	37.0°
2047-01-11 Fri	43	—	unknown	18:50–01:20 (marginal, 6.5 h)	72.6° 20:45	11.31	100%	50.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-12-13&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.