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: 05-20 (100), 05-21 (100), 05-22 (100), 05-23 (100), 05-24 (100) — by astronomy; check the weather when the night is within four days.

2037-05-20astronomy score per night — click a bar for that night2037-06-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-05-20 Wed	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.3	34%	114.3°
2037-05-21 Thu	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.25	45%	109.3°
2037-05-22 Fri	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.21	56%	103.2°
2037-05-23 Sat	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.16	68%	96.4°
2037-05-24 Sun	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:45	5.11	78%	89.3°
2037-05-25 Mon	79	—	unknown	23:20–03:50 (good, 4.5 h)	87.1° 03:45	5.07	87%	82.3°
2037-05-26 Tue	71	—	unknown	00:10–03:50 (good, 3.67 h)	87.1° 03:40	5.02	93%	75.6°
2037-05-27 Wed	61	—	unknown	00:50–03:50 (good, 3.0 h)	87.1° 03:35	4.98	98%	69.7°
2037-05-28 Thu	54	—	unknown	02:40–03:50 (good, 1.17 h)	87.1° 03:30	4.94	100%	65.0°
2037-05-29 Fri	51	—	unknown	03:45–03:50 (good, 0.08 h)	87.1° 03:30	4.9	99%	61.7°
2037-05-30 Sat	55	—	unknown	23:30–01:55 (good, 2.42 h)	87.1° 03:25	4.86	96%	60.2°
2037-05-31 Sun	86	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.82	92%	60.4°
2037-06-01 Mon	95	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.78	85%	62.2°
2037-06-02 Tue	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.75	77%	65.2°
2037-06-03 Wed	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.72	69%	69.4°
2037-06-04 Thu	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:05	4.68	60%	74.3°
2037-06-05 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 03:00	4.65	50%	79.7°
2037-06-06 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.62	41%	85.4°
2037-06-07 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.6	32%	91.4°
2037-06-08 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.57	23%	97.3°
2037-06-09 Tue	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.55	15%	103.1°
2037-06-10 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:40	4.53	9%	108.6°
2037-06-11 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.51	4%	113.3°
2037-06-12 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.49	1%	117.1°
2037-06-13 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.47	0%	119.3°
2037-06-14 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.46	2%	119.8°
2037-06-15 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.45	6%	118.4°
2037-06-16 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:15	4.44	13%	115.2°
2037-06-17 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:15	4.43	21%	110.4°
2037-06-18 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:10	4.43	32%	104.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-05-20&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.