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), 07-13 (2), 07-14 (2), 07-15 (2) — by astronomy; check the weather when the night is within four days.

2041-06-17astronomy score per night — click a bar for that night2041-07-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-06-17 Mon	0	—	unknown	—	72.5° 11:20	4.43	84%	105.9°
2041-06-18 Tue	0	—	unknown	—	72.5° 11:20	4.43	74%	91.5°
2041-06-19 Wed	0	—	unknown	—	72.5° 11:15	4.42	64%	77.1°
2041-06-20 Thu	0	—	unknown	—	72.5° 11:10	4.42	52%	62.9°
2041-06-21 Fri	0	—	unknown	—	72.5° 11:05	4.42	41%	48.9°
2041-06-22 Sat	0	—	unknown	—	72.5° 11:00	4.43	30%	35.2°
2041-06-23 Sun	0	—	unknown	—	72.5° 11:00	4.43	21%	21.7°
2041-06-24 Mon	0	—	unknown	—	72.5° 10:55	4.44	13%	8.7°
2041-06-25 Tue	0	—	unknown	—	72.5° 10:50	4.45	7%	5.6°
2041-06-26 Wed	0	—	unknown	—	72.5° 10:45	4.46	2%	18.0°
2041-06-27 Thu	0	—	unknown	—	72.5° 10:45	4.47	0%	30.6°
2041-06-28 Fri	0	—	unknown	—	72.5° 10:40	4.49	0%	43.0°
2041-06-29 Sat	0	—	unknown	—	72.5° 10:35	4.5	2%	55.3°
2041-06-30 Sun	0	—	unknown	—	72.5° 10:30	4.52	6%	67.4°
2041-07-01 Mon	0	—	unknown	—	72.5° 10:25	4.55	11%	79.3°
2041-07-02 Tue	0	—	unknown	—	72.5° 10:25	4.57	18%	91.2°
2041-07-03 Wed	0	—	unknown	—	72.5° 10:20	4.59	26%	103.0°
2041-07-04 Thu	0	—	unknown	—	72.5° 10:15	4.62	34%	114.8°
2041-07-05 Fri	0	—	unknown	—	72.5° 10:10	4.65	44%	126.8°
2041-07-06 Sat	0	—	unknown	—	72.5° 10:05	4.68	53%	138.9°
2041-07-07 Sun	1	—	unknown	—	72.5° 10:05	4.71	63%	151.2°
2041-07-08 Mon	1	—	unknown	—	72.5° 10:00	4.74	73%	163.8°
2041-07-09 Tue	1	—	unknown	—	72.5° 09:55	4.78	82%	176.1°
2041-07-10 Wed	1	—	unknown	—	72.5° 09:50	4.81	89%	168.9°
2041-07-11 Thu	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:50	4.85	95%	155.1°
2041-07-12 Fri	2	—	unknown	—	72.5° 09:45	4.89	99%	140.7°
2041-07-13 Sat	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:40	4.93	100%	126.1°
2041-07-14 Sun	2	—	unknown	—	72.5° 09:35	4.97	98%	111.2°
2041-07-15 Mon	2	—	unknown	—	72.5° 09:30	5.01	93%	96.2°
2041-07-16 Tue	2	—	unknown	—	72.5° 09:30	5.06	86%	81.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-06-17&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.