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: 07-16 (4), 07-15 (3), 07-12 (2), 07-13 (2), 07-14 (2) — by astronomy; check the weather when the night is within four days.

2035-06-17astronomy score per night — click a bar for that night2035-07-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-06-17 Sun	0	—	unknown	—	72.5° 11:25	4.44	92%	169.8°
2035-06-18 Mon	0	—	unknown	—	72.5° 11:20	4.43	97%	168.4°
2035-06-19 Tue	0	—	unknown	—	72.5° 11:15	4.43	99%	158.9°
2035-06-20 Wed	0	—	unknown	—	72.5° 11:10	4.42	100%	147.9°
2035-06-21 Thu	0	—	unknown	—	72.5° 11:10	4.42	99%	136.5°
2035-06-22 Fri	0	—	unknown	—	72.5° 11:05	4.42	96%	124.8°
2035-06-23 Sat	0	—	unknown	—	72.5° 11:00	4.43	91%	113.0°
2035-06-24 Sun	0	—	unknown	—	72.5° 10:55	4.43	85%	101.1°
2035-06-25 Mon	0	—	unknown	—	72.5° 10:50	4.44	78%	89.0°
2035-06-26 Tue	0	—	unknown	—	72.5° 10:50	4.45	69%	76.7°
2035-06-27 Wed	0	—	unknown	—	72.5° 10:45	4.47	59%	64.1°
2035-06-28 Thu	0	—	unknown	—	72.5° 10:40	4.48	48%	51.2°
2035-06-29 Fri	0	—	unknown	—	72.5° 10:35	4.5	38%	38.1°
2035-06-30 Sat	0	—	unknown	—	72.5° 10:35	4.51	27%	24.9°
2035-07-01 Sun	0	—	unknown	—	72.5° 10:30	4.53	17%	12.7°
2035-07-02 Mon	0	—	unknown	—	72.5° 10:25	4.56	9%	10.9°
2035-07-03 Tue	0	—	unknown	—	72.5° 10:20	4.58	4%	22.8°
2035-07-04 Wed	0	—	unknown	—	72.5° 10:15	4.61	0%	37.1°
2035-07-05 Thu	0	—	unknown	—	72.5° 10:15	4.63	0%	51.9°
2035-07-06 Fri	0	—	unknown	—	72.5° 10:10	4.66	4%	66.7°
2035-07-07 Sat	1	—	unknown	—	72.5° 10:05	4.69	9%	81.2°
2035-07-08 Sun	1	—	unknown	—	72.5° 10:00	4.73	17%	95.3°
2035-07-09 Mon	1	—	unknown	—	72.5° 09:55	4.76	26%	108.9°
2035-07-10 Tue	1	—	unknown	—	72.5° 09:55	4.79	36%	122.0°
2035-07-11 Wed	1	—	unknown	—	72.5° 09:50	4.83	46%	134.7°
2035-07-12 Thu	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:45	4.87	56%	146.8°
2035-07-13 Fri	2	—	unknown	04:35–04:45 (marginal, 0.17 h)	72.5° 09:40	4.91	66%	158.3°
2035-07-14 Sat	2	—	unknown	04:30–04:45 (marginal, 0.25 h)	72.5° 09:40	4.95	75%	168.0°
2035-07-15 Sun	3	—	unknown	04:30–04:50 (marginal, 0.33 h)	72.5° 09:35	4.99	82%	169.8°
2035-07-16 Mon	4	—	unknown	04:25–04:50 (marginal, 0.42 h)	72.5° 09:30	5.03	89%	161.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-06-17&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.