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: 06-27 (100), 06-28 (100), 06-29 (100), 06-30 (100), 07-01 (100) — by astronomy; check the weather when the night is within four days.

2031-06-27astronomy score per night — click a bar for that night2031-07-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-06-27 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:35	4.46	49%	98.4°
2031-06-28 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:30	4.48	60%	91.6°
2031-06-29 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 01:30	4.5	70%	84.4°
2031-06-30 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:25	4.51	80%	77.2°
2031-07-01 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:20	4.53	88%	70.4°
2031-07-02 Wed	67	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:15	4.56	95%	64.5°
2031-07-03 Thu	54	—	unknown	02:20–03:45 (good, 1.42 h)	87.1° 01:10	4.58	99%	60.2°
2031-07-04 Fri	48	—	unknown	23:10–03:45 (marginal, 4.58 h)	87.1° 01:10	4.6	100%	57.9°
2031-07-05 Sat	51	—	unknown	23:10–23:55 (good, 0.75 h)	87.1° 01:05	4.63	98%	58.2°
2031-07-06 Sun	60	—	unknown	23:10–01:25 (good, 2.25 h)	87.1° 01:00	4.66	93%	60.9°
2031-07-07 Mon	73	—	unknown	23:10–03:50 (good, 4.67 h)	87.1° 00:55	4.69	86%	65.5°
2031-07-08 Tue	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.1° 00:50	4.72	77%	71.5°
2031-07-09 Wed	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.1° 00:50	4.76	66%	78.1°
2031-07-10 Thu	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.1° 00:45	4.79	56%	85.1°
2031-07-11 Fri	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.1° 00:40	4.83	45%	92.0°
2031-07-12 Sat	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.1° 00:35	4.87	36%	98.7°
2031-07-13 Sun	100	—	unknown	23:00–03:55 (good, 4.92 h)	87.1° 00:35	4.91	26%	104.9°
2031-07-14 Mon	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:30	4.95	18%	110.5°
2031-07-15 Tue	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:25	4.99	12%	115.2°
2031-07-16 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:20	5.03	6%	118.9°
2031-07-17 Thu	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:15	5.08	2%	121.3°
2031-07-18 Fri	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.1° 00:15	5.12	0%	122.2°
2031-07-19 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.1° 00:10	5.17	0%	121.7°
2031-07-20 Sun	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.1° 00:05	5.21	2%	119.6°
2031-07-21 Mon	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.1° 00:00	5.26	5%	116.1°
2031-07-22 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.1° 23:55	5.31	10%	111.6°
2031-07-23 Wed	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.1° 23:55	5.36	17%	106.1°
2031-07-24 Thu	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 23:50	5.41	25%	99.9°
2031-07-25 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 23:45	5.46	34%	93.3°
2031-07-26 Sat	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 23:40	5.51	45%	86.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-06-27&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.