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.

2035-08-31astronomy score per night — click a bar for that night2035-09-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2035-09-12 Wed	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:40	8.2	80%	123.1°
2035-09-13 Thu	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:40	8.26	87%	111.2°
2035-09-14 Fri	100	—	unknown	00:50–05:30 (good, 4.67 h)	72.5° 05:35	8.31	93%	99.1°
2035-09-15 Sat	80	—	unknown	01:35–05:30 (good, 3.92 h)	72.5° 05:30	8.36	97%	86.7°
2035-09-16 Sun	61	—	unknown	03:00–05:30 (good, 2.5 h)	72.5° 05:25	8.42	100%	74.1°
2035-09-17 Mon	44	—	unknown	05:25–05:30 (good, 0.08 h)	72.5° 05:20	8.47	100%	61.2°
2035-09-18 Tue	30	—	unknown	00:20–05:35 (marginal, 5.25 h)	72.5° 05:20	8.52	98%	48.1°
2035-09-19 Wed	21	—	unknown	00:25–05:35 (marginal, 5.17 h)	72.5° 05:15	8.57	94%	35.0°
2035-09-20 Thu	21	—	unknown	00:10–05:35 (marginal, 5.42 h)	72.5° 05:10	8.62	87%	22.1°
2035-09-21 Fri	29	—	unknown	23:50–05:35 (marginal, 5.75 h)	72.5° 05:05	8.67	79%	11.2°
2035-09-22 Sat	42	—	unknown	23:35–05:40 (marginal, 6.08 h)	72.5° 05:05	8.73	69%	12.1°
2035-09-23 Sun	60	—	unknown	00:55–03:55 (good, 3.0 h)	72.5° 05:00	8.78	58%	23.7°
2035-09-24 Mon	81	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 04:55	8.83	46%	37.1°
2035-09-25 Tue	89	—	unknown	23:45–05:40 (good, 5.92 h)	72.5° 04:50	8.88	35%	50.9°
2035-09-26 Wed	97	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:45	8.93	25%	64.8°
2035-09-27 Thu	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:45	8.98	16%	78.7°
2035-09-28 Fri	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:40	9.02	8%	92.5°
2035-09-29 Sat	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.5° 04:35	9.07	3%	106.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-08-31&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.