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: 04-10 (1), 04-11 (1), 04-12 (1), 04-13 (1) — by astronomy; check the weather when the night is within four days.

2044-04-10astronomy score per night — click a bar for that night2044-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-04-10 Sun	1	—	unknown	—	72.5° 15:50	7.54	98%	124.5°
2044-04-11 Mon	1	—	unknown	—	72.6° 15:50	7.49	100%	137.4°
2044-04-12 Tue	1	—	unknown	—	72.6° 15:45	7.43	100%	150.1°
2044-04-13 Wed	1	—	unknown	—	72.6° 15:40	7.37	98%	162.6°
2044-04-14 Thu	0	—	unknown	—	72.6° 15:35	7.31	94%	174.8°
2044-04-15 Fri	0	—	unknown	—	72.5° 15:35	7.26	88%	173.1°
2044-04-16 Sat	0	—	unknown	—	72.6° 15:30	7.2	81%	161.2°
2044-04-17 Sun	0	—	unknown	—	72.6° 15:25	7.14	73%	149.3°
2044-04-18 Mon	0	—	unknown	—	72.6° 15:20	7.08	65%	137.5°
2044-04-19 Tue	0	—	unknown	—	72.5° 15:15	7.02	55%	125.6°
2044-04-20 Wed	0	—	unknown	—	72.6° 15:15	6.97	46%	113.6°
2044-04-21 Thu	0	—	unknown	—	72.6° 15:10	6.91	36%	101.3°
2044-04-22 Fri	0	—	unknown	—	72.6° 15:05	6.85	27%	88.8°
2044-04-23 Sat	0	—	unknown	—	72.6° 15:00	6.79	18%	75.8°
2044-04-24 Sun	0	—	unknown	—	72.5° 14:55	6.73	11%	62.4°
2044-04-25 Mon	0	—	unknown	—	72.6° 14:55	6.67	5%	48.6°
2044-04-26 Tue	0	—	unknown	—	72.6° 14:50	6.62	1%	34.4°
2044-04-27 Wed	0	—	unknown	—	72.6° 14:45	6.56	0%	19.9°
2044-04-28 Thu	0	—	unknown	—	72.6° 14:40	6.5	2%	5.2°
2044-04-29 Fri	0	—	unknown	—	72.5° 14:40	6.44	6%	9.7°
2044-04-30 Sat	0	—	unknown	—	72.6° 14:35	6.38	14%	24.5°
2044-05-01 Sun	0	—	unknown	—	72.6° 14:30	6.33	23%	39.1°
2044-05-02 Mon	0	—	unknown	—	72.6° 14:25	6.27	33%	53.5°
2044-05-03 Tue	0	—	unknown	—	72.6° 14:20	6.21	44%	67.6°
2044-05-04 Wed	0	—	unknown	—	72.6° 14:20	6.15	56%	81.5°
2044-05-05 Thu	0	—	unknown	—	72.6° 14:15	6.1	66%	95.0°
2044-05-06 Fri	0	—	unknown	—	72.6° 14:10	6.04	76%	108.2°
2044-05-07 Sat	0	—	unknown	—	72.6° 14:05	5.98	84%	121.2°
2044-05-08 Sun	0	—	unknown	—	72.5° 14:00	5.93	91%	134.0°
2044-05-09 Mon	0	—	unknown	—	72.6° 14:00	5.87	96%	146.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-10&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.