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

2042-06-12astronomy score per night — click a bar for that night2042-07-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-06-12 Thu	0	—	unknown	—	72.5° 11:45	4.49	29%	42.9°
2042-06-13 Fri	0	—	unknown	—	72.5° 11:40	4.48	19%	28.6°
2042-06-14 Sat	0	—	unknown	—	72.5° 11:35	4.46	11%	14.2°
2042-06-15 Sun	0	—	unknown	—	72.5° 11:30	4.45	5%	1.3°
2042-06-16 Mon	0	—	unknown	—	72.5° 11:25	4.44	1%	14.4°
2042-06-17 Tue	0	—	unknown	—	72.5° 11:25	4.43	0%	28.4°
2042-06-18 Wed	0	—	unknown	—	72.5° 11:20	4.43	2%	42.1°
2042-06-19 Thu	0	—	unknown	—	72.5° 11:15	4.42	6%	55.4°
2042-06-20 Fri	0	—	unknown	—	72.5° 11:10	4.42	11%	68.4°
2042-06-21 Sat	0	—	unknown	—	72.5° 11:05	4.42	18%	81.1°
2042-06-22 Sun	0	—	unknown	—	72.5° 11:05	4.42	26%	93.5°
2042-06-23 Mon	0	—	unknown	—	72.5° 11:00	4.43	36%	105.6°
2042-06-24 Tue	0	—	unknown	—	72.5° 10:55	4.44	45%	117.5°
2042-06-25 Wed	0	—	unknown	—	72.5° 10:50	4.44	54%	129.4°
2042-06-26 Thu	0	—	unknown	—	72.5° 10:50	4.46	64%	141.3°
2042-06-27 Fri	0	—	unknown	—	72.5° 10:45	4.47	72%	153.2°
2042-06-28 Sat	0	—	unknown	—	72.5° 10:40	4.48	81%	165.3°
2042-06-29 Sun	0	—	unknown	—	72.5° 10:35	4.5	88%	177.4°
2042-06-30 Mon	0	—	unknown	—	72.5° 10:30	4.52	94%	169.7°
2042-07-01 Tue	0	—	unknown	—	72.5° 10:30	4.54	98%	156.9°
2042-07-02 Wed	0	—	unknown	—	72.5° 10:25	4.56	100%	143.8°
2042-07-03 Thu	0	—	unknown	—	72.5° 10:20	4.59	99%	130.3°
2042-07-04 Fri	0	—	unknown	—	72.5° 10:15	4.61	97%	116.6°
2042-07-05 Sat	0	—	unknown	—	72.5° 10:10	4.64	92%	102.7°
2042-07-06 Sun	0	—	unknown	—	72.5° 10:10	4.67	84%	88.7°
2042-07-07 Mon	0	—	unknown	—	72.5° 10:05	4.7	75%	74.5°
2042-07-08 Tue	0	—	unknown	—	72.5° 10:00	4.73	65%	60.3°
2042-07-09 Wed	0	—	unknown	—	72.5° 09:55	4.77	54%	46.1°
2042-07-10 Thu	1	—	unknown	—	72.5° 09:55	4.8	42%	31.9°
2042-07-11 Fri	1	—	unknown	—	72.5° 09:50	4.84	31%	17.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-06-12&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.