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), 04-13 (1), 04-14 (1) — by astronomy; check the weather when the night is within four days.

2036-04-11astronomy score per night — click a bar for that night2036-05-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-04-11 Fri	1	—	unknown	—	72.5° 15:50	7.49	98%	154.9°
2036-04-12 Sat	1	—	unknown	—	72.5° 15:45	7.43	95%	166.3°
2036-04-13 Sun	1	—	unknown	—	72.5° 15:40	7.38	89%	170.5°
2036-04-14 Mon	1	—	unknown	—	72.5° 15:35	7.32	82%	162.3°
2036-04-15 Tue	0	—	unknown	—	72.5° 15:35	7.26	74%	151.2°
2036-04-16 Wed	0	—	unknown	—	72.5° 15:30	7.2	66%	139.6°
2036-04-17 Thu	0	—	unknown	—	72.5° 15:25	7.14	56%	128.0°
2036-04-18 Fri	0	—	unknown	—	72.5° 15:20	7.09	47%	116.4°
2036-04-19 Sat	0	—	unknown	—	72.5° 15:15	7.03	37%	104.7°
2036-04-20 Sun	0	—	unknown	—	72.5° 15:15	6.97	28%	92.9°
2036-04-21 Mon	0	—	unknown	—	72.5° 15:10	6.91	20%	80.9°
2036-04-22 Tue	0	—	unknown	—	72.5° 15:05	6.85	13%	68.7°
2036-04-23 Wed	0	—	unknown	—	72.5° 15:00	6.8	7%	56.2°
2036-04-24 Thu	0	—	unknown	—	72.5° 14:55	6.74	3%	43.5°
2036-04-25 Fri	0	—	unknown	—	72.5° 14:55	6.68	0%	30.6°
2036-04-26 Sat	0	—	unknown	—	72.5° 14:50	6.62	0%	18.1°
2036-04-27 Sun	0	—	unknown	—	72.5° 14:45	6.56	3%	9.3°
2036-04-28 Mon	0	—	unknown	—	72.5° 14:40	6.5	8%	15.1°
2036-04-29 Tue	0	—	unknown	—	72.5° 14:40	6.45	15%	27.8°
2036-04-30 Wed	0	—	unknown	—	72.5° 14:35	6.39	25%	41.4°
2036-05-01 Thu	0	—	unknown	—	72.5° 14:30	6.33	35%	55.3°
2036-05-02 Fri	0	—	unknown	—	72.5° 14:25	6.27	46%	69.3°
2036-05-03 Sat	0	—	unknown	—	72.5° 14:20	6.21	58%	83.2°
2036-05-04 Sun	0	—	unknown	—	72.5° 14:20	6.16	69%	97.1°
2036-05-05 Mon	0	—	unknown	—	72.5° 14:15	6.1	78%	110.8°
2036-05-06 Tue	0	—	unknown	—	72.5° 14:10	6.04	87%	124.4°
2036-05-07 Wed	0	—	unknown	—	72.5° 14:05	5.99	93%	137.7°
2036-05-08 Thu	0	—	unknown	—	72.5° 14:00	5.93	98%	150.6°
2036-05-09 Fri	0	—	unknown	—	72.5° 14:00	5.87	100%	162.6°
2036-05-10 Sat	0	—	unknown	—	72.5° 13:55	5.82	99%	170.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-04-11&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.