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: 05-28 (100), 05-29 (100), 05-30 (100), 05-31 (100), 06-01 (100) — by astronomy; check the weather when the night is within four days.

2035-05-20astronomy score per night — click a bar for that night2035-06-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-05-20 Sun	62	—	unknown	01:10–04:00 (good, 2.83 h)	87.1° 04:05	5.33	98%	72.0°
2035-05-21 Mon	56	—	unknown	02:40–04:00 (good, 1.33 h)	87.1° 04:00	5.28	100%	66.8°
2035-05-22 Tue	51	—	unknown	22:45–03:55 (marginal, 5.17 h)	87.1° 03:55	5.23	99%	62.5°
2035-05-23 Wed	51	—	unknown	22:45–03:55 (marginal, 5.17 h)	87.1° 03:55	5.18	97%	59.5°
2035-05-24 Thu	57	—	unknown	23:55–02:00 (good, 2.08 h)	87.1° 03:50	5.14	93%	57.8°
2035-05-25 Fri	87	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.09	88%	57.6°
2035-05-26 Sat	93	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.05	81%	59.0°
2035-05-27 Sun	98	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.0	73%	61.8°
2035-05-28 Mon	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.96	64%	66.0°
2035-05-29 Tue	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.92	54%	71.2°
2035-05-30 Wed	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.88	44%	77.4°
2035-05-31 Thu	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.84	33%	84.2°
2035-06-01 Fri	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.8	24%	91.5°
2035-06-02 Sat	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.77	15%	99.0°
2035-06-03 Sun	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.73	7%	106.2°
2035-06-04 Mon	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.7	2%	112.8°
2035-06-05 Tue	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:00	4.67	0%	118.1°
2035-06-06 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 03:00	4.64	1%	121.5°
2035-06-07 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.61	5%	122.4°
2035-06-08 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.59	12%	120.9°
2035-06-09 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.56	20%	117.2°
2035-06-10 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.54	30%	112.0°
2035-06-11 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:40	4.52	40%	105.9°
2035-06-12 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.5	51%	99.2°
2035-06-13 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.48	61%	92.4°
2035-06-14 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.47	71%	85.7°
2035-06-15 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.46	79%	79.2°
2035-06-16 Sat	78	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.44	87%	73.2°
2035-06-17 Sun	67	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 02:15	4.44	92%	67.9°
2035-06-18 Mon	57	—	unknown	01:15–03:40 (good, 2.42 h)	87.1° 02:10	4.43	97%	63.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-20&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.