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: 07-11 (2), 07-12 (2), 07-08 (1), 07-09 (1), 07-10 (1) — by astronomy; check the weather when the night is within four days.

2037-06-13astronomy score per night — click a bar for that night2037-07-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-06-13 Sat	0	—	unknown	—	72.5° 11:40	4.47	0%	27.1°
2037-06-14 Sun	0	—	unknown	—	72.5° 11:35	4.46	2%	40.4°
2037-06-15 Mon	0	—	unknown	—	72.5° 11:30	4.45	6%	54.1°
2037-06-16 Tue	0	—	unknown	—	72.5° 11:25	4.44	13%	68.0°
2037-06-17 Wed	0	—	unknown	—	72.5° 11:20	4.43	21%	82.1°
2037-06-18 Thu	0	—	unknown	—	72.5° 11:20	4.43	32%	96.2°
2037-06-19 Fri	0	—	unknown	—	72.5° 11:15	4.42	43%	110.3°
2037-06-20 Sat	0	—	unknown	—	72.5° 11:10	4.42	54%	124.3°
2037-06-21 Sun	0	—	unknown	—	72.5° 11:05	4.42	65%	138.1°
2037-06-22 Mon	0	—	unknown	—	72.5° 11:00	4.43	76%	151.5°
2037-06-23 Tue	0	—	unknown	—	72.5° 11:00	4.43	85%	164.1°
2037-06-24 Wed	0	—	unknown	—	72.5° 10:55	4.44	92%	171.4°
2037-06-25 Thu	0	—	unknown	—	72.5° 10:50	4.45	97%	163.8°
2037-06-26 Fri	0	—	unknown	—	72.5° 10:45	4.46	99%	151.8°
2037-06-27 Sat	0	—	unknown	—	72.5° 10:45	4.47	100%	139.2°
2037-06-28 Sun	0	—	unknown	—	72.5° 10:40	4.49	98%	126.8°
2037-06-29 Mon	0	—	unknown	—	72.5° 10:35	4.51	95%	114.5°
2037-06-30 Tue	0	—	unknown	—	72.5° 10:30	4.52	89%	102.3°
2037-07-01 Wed	0	—	unknown	—	72.5° 10:25	4.55	83%	90.4°
2037-07-02 Thu	0	—	unknown	—	72.5° 10:25	4.57	75%	78.6°
2037-07-03 Fri	0	—	unknown	—	72.5° 10:20	4.59	66%	66.9°
2037-07-04 Sat	0	—	unknown	—	72.5° 10:15	4.62	57%	55.2°
2037-07-05 Sun	0	—	unknown	—	72.5° 10:10	4.65	47%	43.5°
2037-07-06 Mon	0	—	unknown	—	72.5° 10:05	4.68	38%	31.8°
2037-07-07 Tue	0	—	unknown	—	72.5° 10:05	4.71	28%	20.3°
2037-07-08 Wed	1	—	unknown	—	72.5° 10:00	4.74	20%	10.4°
2037-07-09 Thu	1	—	unknown	—	72.5° 09:55	4.78	12%	11.2°
2037-07-10 Fri	1	—	unknown	—	72.5° 09:50	4.81	6%	22.3°
2037-07-11 Sat	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:50	4.85	2%	35.3°
2037-07-12 Sun	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:45	4.89	0%	49.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-06-13&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.