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: 04-04 (7), 04-05 (6), 04-06 (5), 04-07 (3), 04-08 (3) — by astronomy; check the weather when the night is within four days.

2045-04-04astronomy score per night — click a bar for that night2045-05-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-04 Tue	7	—	unknown	20:55–21:55 (marginal, 1.0 h)	72.6° 16:15	7.89	88%	175.6°
2045-04-05 Wed	6	—	unknown	20:55–21:25 (marginal, 0.5 h)	72.6° 16:15	7.84	81%	171.4°
2045-04-06 Thu	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	72.6° 16:10	7.78	72%	158.9°
2045-04-07 Fri	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	72.6° 16:05	7.73	63%	146.7°
2045-04-08 Sat	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.6° 16:00	7.67	54%	134.7°
2045-04-09 Sun	2	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.6° 15:55	7.61	44%	122.8°
2045-04-10 Mon	1	—	unknown	21:00–21:05 (marginal, 0.08 h)	72.6° 15:55	7.56	35%	111.0°
2045-04-11 Tue	1	—	unknown	—	72.6° 15:50	7.5	26%	99.1°
2045-04-12 Wed	1	—	unknown	—	72.6° 15:45	7.44	18%	87.1°
2045-04-13 Thu	1	—	unknown	—	72.6° 15:40	7.39	12%	75.0°
2045-04-14 Fri	1	—	unknown	—	72.6° 15:40	7.33	6%	62.6°
2045-04-15 Sat	0	—	unknown	—	72.6° 15:35	7.27	2%	49.9°
2045-04-16 Sun	0	—	unknown	—	72.6° 15:30	7.21	0%	37.0°
2045-04-17 Mon	0	—	unknown	—	72.6° 15:25	7.15	1%	23.8°
2045-04-18 Tue	0	—	unknown	—	72.6° 15:20	7.1	3%	10.3°
2045-04-19 Wed	0	—	unknown	—	72.6° 15:20	7.04	8%	3.5°
2045-04-20 Thu	0	—	unknown	—	72.6° 15:15	6.98	15%	17.3°
2045-04-21 Fri	0	—	unknown	—	72.6° 15:10	6.92	24%	31.2°
2045-04-22 Sat	0	—	unknown	—	72.6° 15:05	6.86	35%	45.3°
2045-04-23 Sun	0	—	unknown	—	72.6° 15:00	6.81	46%	59.4°
2045-04-24 Mon	0	—	unknown	—	72.6° 15:00	6.75	57%	73.6°
2045-04-25 Tue	0	—	unknown	—	72.6° 14:55	6.69	68%	87.8°
2045-04-26 Wed	0	—	unknown	—	72.6° 14:50	6.63	78%	101.9°
2045-04-27 Thu	0	—	unknown	—	72.6° 14:45	6.57	87%	116.0°
2045-04-28 Fri	0	—	unknown	—	72.6° 14:45	6.51	94%	130.0°
2045-04-29 Sat	0	—	unknown	—	72.6° 14:40	6.46	98%	143.8°
2045-04-30 Sun	0	—	unknown	—	72.6° 14:35	6.4	100%	157.3°
2045-05-01 Mon	0	—	unknown	—	72.6° 14:30	6.34	99%	170.6°
2045-05-02 Tue	0	—	unknown	—	72.6° 14:25	6.28	97%	176.2°
2045-05-03 Wed	0	—	unknown	—	72.6° 14:25	6.22	92%	163.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-04&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.