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: 05-31 (100), 06-01 (100), 06-02 (100), 06-03 (100), 06-11 (100) — by astronomy; check the weather when the night is within four days.

2028-05-31astronomy score per night — click a bar for that night2028-06-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-05-31 Wed	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.81	57%	105.9°
2028-06-01 Thu	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.78	68%	99.9°
2028-06-02 Fri	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.74	78%	93.5°
2028-06-03 Sat	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.71	87%	86.9°
2028-06-04 Sun	79	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:05	4.68	93%	80.6°
2028-06-05 Mon	71	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 03:00	4.65	98%	74.8°
2028-06-06 Tue	63	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.62	100%	69.7°
2028-06-07 Wed	58	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.59	99%	65.8°
2028-06-08 Thu	60	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.57	97%	63.2°
2028-06-09 Fri	88	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.54	92%	62.1°
2028-06-10 Sat	97	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:40	4.52	86%	62.4°
2028-06-11 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.5	79%	64.0°
2028-06-12 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.49	71%	66.8°
2028-06-13 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.47	62%	70.6°
2028-06-14 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.46	52%	75.0°
2028-06-15 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.45	43%	80.1°
2028-06-16 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:15	4.44	34%	85.6°
2028-06-17 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:10	4.43	25%	91.3°
2028-06-18 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:10	4.43	16%	97.1°
2028-06-19 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:05	4.42	10%	102.8°
2028-06-20 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 02:00	4.42	4%	108.1°
2028-06-21 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:55	4.42	1%	112.6°
2028-06-22 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:50	4.43	0%	116.0°
2028-06-23 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:50	4.43	2%	117.8°
2028-06-24 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:45	4.44	6%	117.7°
2028-06-25 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:40	4.45	13%	115.8°
2028-06-26 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:35	4.46	22%	112.2°
2028-06-27 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:35	4.47	32%	107.3°
2028-06-28 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 01:30	4.49	43%	101.4°
2028-06-29 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:25	4.51	55%	95.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-05-31&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.