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 Vega: 05-23 (100), 05-24 (100), 05-25 (100), 05-26 (100), 05-27 (100) — by astronomy; check the weather when the night is within four days.

2030-05-21astronomy score per night — click a bar for that night2030-06-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-05-21 Tue	95	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.27	74%	59.3°
2030-05-22 Wed	99	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.22	64%	61.6°
2030-05-23 Thu	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.17	53%	65.4°
2030-05-24 Fri	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.13	43%	70.3°
2030-05-25 Sat	100	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.08	33%	75.9°
2030-05-26 Sun	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.04	24%	81.9°
2030-05-27 Mon	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.99	16%	88.1°
2030-05-28 Tue	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.95	10%	94.2°
2030-05-29 Wed	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.91	5%	100.2°
2030-05-30 Thu	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.87	2%	105.9°
2030-05-31 Fri	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.83	0%	110.9°
2030-06-01 Sat	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.79	0%	115.3°
2030-06-02 Sun	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.76	2%	118.6°
2030-06-03 Mon	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.73	6%	120.6°
2030-06-04 Tue	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.69	12%	121.1°
2030-06-05 Wed	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:00	4.66	19%	120.1°
2030-06-06 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.63	28%	117.6°
2030-06-07 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.61	37%	113.6°
2030-06-08 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.58	48%	108.4°
2030-06-09 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.56	58%	102.3°
2030-06-10 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:40	4.53	69%	95.3°
2030-06-11 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:40	4.51	79%	87.9°
2030-06-12 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.5	88%	80.5°
2030-06-13 Thu	73	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.48	95%	73.3°
2030-06-14 Fri	60	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.46	99%	67.1°
2030-06-15 Sat	52	—	unknown	23:10–00:35 (good, 1.42 h)	87.1° 02:20	4.45	100%	62.3°
2030-06-16 Sun	53	—	unknown	23:10–00:50 (good, 1.67 h)	87.1° 02:20	4.44	98%	59.5°
2030-06-17 Mon	59	—	unknown	23:10–02:00 (good, 2.83 h)	87.1° 02:15	4.43	93%	58.9°
2030-06-18 Tue	93	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:10	4.43	86%	60.5°
2030-06-19 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:05	4.42	78%	63.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-05-21&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.