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: 08-31 (100), 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100) — by astronomy; check the weather when the night is within four days.

2035-08-13astronomy score per night — click a bar for that night2035-09-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-08-13 Mon	57	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:40	6.52	77%	153.8°
2035-08-14 Tue	57	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:35	6.57	85%	142.6°
2035-08-15 Wed	58	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:30	6.63	91%	131.0°
2035-08-16 Thu	59	—	unknown	02:30–04:50 (good, 2.33 h)	72.5° 07:30	6.69	96%	119.3°
2035-08-17 Fri	48	—	unknown	02:35–04:50 (good, 2.25 h)	72.5° 07:25	6.75	99%	107.3°
2035-08-18 Sat	40	—	unknown	02:50–04:50 (good, 2.0 h)	72.5° 07:20	6.8	100%	95.1°
2035-08-19 Sun	33	—	unknown	03:50–04:55 (good, 1.08 h)	72.5° 07:15	6.86	99%	82.7°
2035-08-20 Mon	27	—	unknown	01:55–04:55 (marginal, 3.0 h)	72.5° 07:10	6.92	96%	70.2°
2035-08-21 Tue	21	—	unknown	01:55–04:55 (marginal, 3.0 h)	72.5° 07:10	6.98	91%	57.4°
2035-08-22 Wed	19	—	unknown	01:55–05:00 (marginal, 3.08 h)	72.5° 07:05	7.03	85%	44.5°
2035-08-23 Thu	18	—	unknown	01:50–05:00 (marginal, 3.17 h)	72.5° 07:00	7.09	76%	31.6°
2035-08-24 Fri	24	—	unknown	01:35–05:00 (marginal, 3.42 h)	72.5° 06:55	7.15	66%	19.1°
2035-08-25 Sat	34	—	unknown	04:40–05:00 (good, 0.33 h)	72.5° 06:55	7.21	55%	9.8°
2035-08-26 Sun	46	—	unknown	02:05–05:05 (good, 3.0 h)	72.5° 06:50	7.26	44%	14.5°
2035-08-27 Mon	60	—	unknown	01:50–05:05 (good, 3.25 h)	72.5° 06:45	7.32	32%	26.9°
2035-08-28 Tue	76	—	unknown	01:35–05:05 (good, 3.5 h)	72.5° 06:40	7.38	22%	40.6°
2035-08-29 Wed	89	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:35	7.43	13%	54.8°
2035-08-30 Thu	98	—	unknown	01:25–05:10 (good, 3.75 h)	72.5° 06:35	7.49	6%	69.1°
2035-08-31 Fri	100	—	unknown	01:25–05:10 (good, 3.75 h)	72.5° 06:30	7.55	2%	83.4°
2035-09-01 Sat	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.5° 06:25	7.6	0%	97.5°
2035-09-02 Sun	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.5° 06:20	7.66	1%	111.4°
2035-09-03 Mon	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.5° 06:15	7.71	4%	124.9°
2035-09-04 Tue	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:15	7.77	10%	138.0°
2035-09-05 Wed	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:10	7.82	17%	150.4°
2035-09-06 Thu	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:05	7.88	25%	161.9°
2035-09-07 Fri	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:00	7.93	34%	170.1°
2035-09-08 Sat	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 06:00	7.99	43%	167.2°
2035-09-09 Sun	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 05:55	8.04	53%	157.3°
2035-09-10 Mon	100	—	unknown	00:50–05:25 (good, 4.58 h)	72.5° 05:50	8.1	62%	146.3°
2035-09-11 Tue	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:45	8.15	71%	134.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-08-13&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.