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: 04-07 (4), 04-08 (3), 04-09 (2), 04-10 (1), 04-11 (1) — by astronomy; check the weather when the night is within four days.

2046-04-07astronomy score per night — click a bar for that night2046-05-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-04-07 Sat	4	—	unknown	21:00–21:15 (marginal, 0.25 h)	72.6° 16:05	7.74	2%	25.4°
2046-04-08 Sun	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.6° 16:00	7.68	6%	13.0°
2046-04-09 Mon	2	—	unknown	21:00–21:05 (marginal, 0.08 h)	72.6° 16:00	7.63	11%	0.8°
2046-04-10 Tue	1	—	unknown	—	72.6° 15:55	7.57	18%	12.2°
2046-04-11 Wed	1	—	unknown	—	72.6° 15:50	7.51	27%	25.1°
2046-04-12 Thu	1	—	unknown	—	72.6° 15:45	7.46	37%	38.2°
2046-04-13 Fri	0	—	unknown	—	72.6° 15:45	7.4	48%	51.7°
2046-04-14 Sat	0	—	unknown	—	72.6° 15:40	7.34	59%	65.5°
2046-04-15 Sun	0	—	unknown	—	72.6° 15:35	7.28	70%	79.7°
2046-04-16 Mon	0	—	unknown	—	72.6° 15:30	7.23	80%	94.2°
2046-04-17 Tue	0	—	unknown	—	72.6° 15:25	7.17	88%	108.9°
2046-04-18 Wed	0	—	unknown	—	72.6° 15:25	7.11	95%	123.8°
2046-04-19 Thu	0	—	unknown	—	72.6° 15:20	7.05	99%	138.8°
2046-04-20 Fri	0	—	unknown	—	72.6° 15:15	6.99	100%	153.6°
2046-04-21 Sat	0	—	unknown	—	72.6° 15:10	6.94	98%	168.2°
2046-04-22 Sun	0	—	unknown	—	72.6° 15:05	6.88	94%	177.4°
2046-04-23 Mon	0	—	unknown	—	72.6° 15:05	6.82	87%	163.7°
2046-04-24 Tue	0	—	unknown	—	72.6° 15:00	6.76	79%	150.3°
2046-04-25 Wed	0	—	unknown	—	72.6° 14:55	6.7	70%	137.3°
2046-04-26 Thu	0	—	unknown	—	72.6° 14:50	6.64	60%	124.7°
2046-04-27 Fri	0	—	unknown	—	72.6° 14:50	6.59	50%	112.5°
2046-04-28 Sat	0	—	unknown	—	72.6° 14:45	6.53	41%	100.4°
2046-04-29 Sun	0	—	unknown	—	72.6° 14:40	6.47	32%	88.5°
2046-04-30 Mon	0	—	unknown	—	72.6° 14:35	6.41	23%	76.7°
2046-05-01 Tue	0	—	unknown	—	72.6° 14:30	6.35	16%	64.9°
2046-05-02 Wed	0	—	unknown	—	72.6° 14:30	6.3	10%	53.0°
2046-05-03 Thu	0	—	unknown	—	72.6° 14:25	6.24	5%	41.0°
2046-05-04 Fri	0	—	unknown	—	72.6° 14:20	6.18	2%	28.8°
2046-05-05 Sat	0	—	unknown	—	72.6° 14:15	6.12	0%	16.4°
2046-05-06 Sun	0	—	unknown	—	72.6° 14:10	6.07	1%	3.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-04-07&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.