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

2035-04-11astronomy score per night — click a bar for that night2035-05-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-04-11 Wed	1	—	unknown	—	72.5° 15:50	7.53	16%	13.2°
2035-04-12 Thu	1	—	unknown	—	72.5° 15:45	7.48	26%	25.7°
2035-04-13 Fri	0	—	unknown	—	72.5° 15:45	7.42	37%	39.4°
2035-04-14 Sat	0	—	unknown	—	72.5° 15:40	7.36	48%	53.1°
2035-04-15 Sun	0	—	unknown	—	72.5° 15:35	7.3	59%	66.8°
2035-04-16 Mon	0	—	unknown	—	72.5° 15:30	7.25	70%	80.2°
2035-04-17 Tue	0	—	unknown	—	72.5° 15:30	7.19	79%	93.5°
2035-04-18 Wed	0	—	unknown	—	72.5° 15:25	7.13	87%	106.5°
2035-04-19 Thu	0	—	unknown	—	72.5° 15:20	7.07	93%	119.2°
2035-04-20 Fri	0	—	unknown	—	72.5° 15:15	7.01	97%	131.8°
2035-04-21 Sat	0	—	unknown	—	72.5° 15:10	6.96	100%	144.0°
2035-04-22 Sun	0	—	unknown	—	72.5° 15:10	6.9	100%	155.7°
2035-04-23 Mon	0	—	unknown	—	72.5° 15:05	6.84	98%	166.2°
2035-04-24 Tue	0	—	unknown	—	72.5° 15:00	6.78	94%	170.8°
2035-04-25 Wed	0	—	unknown	—	72.5° 14:55	6.72	90%	163.7°
2035-04-26 Thu	0	—	unknown	—	72.5° 14:50	6.67	83%	153.1°
2035-04-27 Fri	0	—	unknown	—	72.5° 14:50	6.61	75%	141.9°
2035-04-28 Sat	0	—	unknown	—	72.5° 14:45	6.55	67%	130.3°
2035-04-29 Sun	0	—	unknown	—	72.5° 14:40	6.49	57%	118.5°
2035-04-30 Mon	0	—	unknown	—	72.5° 14:35	6.43	48%	106.6°
2035-05-01 Tue	0	—	unknown	—	72.5° 14:35	6.37	38%	94.3°
2035-05-02 Wed	0	—	unknown	—	72.5° 14:30	6.32	28%	81.6°
2035-05-03 Thu	0	—	unknown	—	72.5° 14:25	6.26	19%	68.6°
2035-05-04 Fri	0	—	unknown	—	72.5° 14:20	6.2	11%	55.1°
2035-05-05 Sat	0	—	unknown	—	72.5° 14:15	6.14	5%	41.3°
2035-05-06 Sun	0	—	unknown	—	72.5° 14:15	6.09	1%	27.3°
2035-05-07 Mon	0	—	unknown	—	72.5° 14:10	6.03	0%	14.2°
2035-05-08 Tue	0	—	unknown	—	72.5° 14:05	5.97	2%	9.9°
2035-05-09 Wed	0	—	unknown	—	72.5° 14:00	5.92	7%	20.9°
2035-05-10 Thu	0	—	unknown	—	72.5° 13:55	5.86	14%	34.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-04-11&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.