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: 12-27 (100), 12-28 (100), 12-29 (100), 12-30 (100), 12-31 (100) — by astronomy; check the weather when the night is within four days.

2034-12-23astronomy score per night — click a bar for that night2035-01-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-12-23 Sat	25	—	unknown	18:40–20:50 (marginal, 2.17 h)	72.5° 22:00	11.51	97%	15.0°
2034-12-24 Sun	27	—	unknown	18:40–21:15 (marginal, 2.58 h)	72.5° 21:55	11.5	100%	28.6°
2034-12-25 Mon	46	—	unknown	18:40–01:05 (marginal, 6.42 h)	72.5° 21:50	11.5	99%	43.2°
2034-12-26 Tue	65	—	unknown	18:40–20:50 (good, 2.17 h)	72.5° 21:50	11.5	96%	57.7°
2034-12-27 Wed	100	—	unknown	18:40–00:05 (good, 5.42 h)	72.5° 21:45	11.49	91%	72.0°
2034-12-28 Thu	100	—	unknown	18:40–01:45 (good, 7.08 h)	72.5° 21:40	11.48	83%	85.9°
2034-12-29 Fri	100	—	unknown	18:40–02:25 (good, 7.75 h)	72.5° 21:35	11.48	74%	99.4°
2034-12-30 Sat	100	—	unknown	18:40–02:35 (good, 7.92 h)	72.5° 21:30	11.47	65%	112.3°
2034-12-31 Sun	100	—	unknown	18:45–02:35 (good, 7.83 h)	72.5° 21:30	11.46	55%	124.8°
2035-01-01 Mon	100	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:25	11.45	45%	136.9°
2035-01-02 Tue	100	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:20	11.44	36%	148.6°
2035-01-03 Wed	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.5° 21:15	11.43	27%	159.7°
2035-01-04 Thu	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.5° 21:15	11.42	19%	169.0°
2035-01-05 Fri	100	—	unknown	18:45–02:20 (good, 7.58 h)	72.5° 21:10	11.4	12%	169.6°
2035-01-06 Sat	100	—	unknown	18:50–02:15 (good, 7.42 h)	72.5° 21:05	11.39	7%	160.7°
2035-01-07 Sun	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.5° 21:00	11.38	3%	149.7°
2035-01-08 Mon	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.5° 20:55	11.36	1%	138.1°
2035-01-09 Tue	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:55	11.34	0%	126.2°
2035-01-10 Wed	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.5° 20:50	11.33	2%	114.1°
2035-01-11 Thu	100	—	unknown	18:50–01:55 (good, 7.08 h)	72.5° 20:45	11.31	5%	101.8°
2035-01-12 Fri	100	—	unknown	18:55–01:50 (good, 6.92 h)	72.5° 20:40	11.29	11%	89.2°
2035-01-13 Sat	100	—	unknown	18:55–01:50 (good, 6.92 h)	72.5° 20:35	11.27	18%	76.5°
2035-01-14 Sun	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.5° 20:35	11.25	26%	63.6°
2035-01-15 Mon	94	—	unknown	18:55–01:40 (good, 6.75 h)	72.5° 20:30	11.23	36%	50.4°
2035-01-16 Tue	85	—	unknown	18:55–01:35 (good, 6.67 h)	72.5° 20:25	11.21	47%	37.2°
2035-01-17 Wed	64	—	unknown	21:05–01:00 (good, 3.92 h)	72.5° 20:20	11.18	58%	24.0°
2035-01-18 Thu	47	—	unknown	19:00–01:50 (marginal, 6.83 h)	72.5° 20:20	11.16	69%	12.1°
2035-01-19 Fri	30	—	unknown	19:00–01:30 (marginal, 6.5 h)	72.5° 20:15	11.14	80%	11.1°
2035-01-20 Sat	22	—	unknown	19:00–01:05 (marginal, 6.08 h)	72.5° 20:10	11.11	88%	22.9°
2035-01-21 Sun	24	—	unknown	19:00–22:55 (marginal, 3.92 h)	72.5° 20:05	11.09	95%	36.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-12-23&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.