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: 07-25 (100), 07-26 (100), 07-27 (100), 07-28 (100), 07-29 (100) — by astronomy; check the weather when the night is within four days.

2030-07-25astronomy score per night — click a bar for that night2030-08-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-07-25 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 23:45	5.48	18%	113.1°
2030-07-26 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 23:40	5.53	12%	117.0°
2030-07-27 Sat	100	—	unknown	22:45–04:20 (good, 5.58 h)	87.1° 23:35	5.58	6%	119.7°
2030-07-28 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:35	5.63	2%	121.0°
2030-07-29 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:30	5.69	0%	120.8°
2030-07-30 Tue	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:25	5.74	0%	118.9°
2030-07-31 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:20	5.79	2%	115.5°
2030-08-01 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:15	5.85	7%	110.8°
2030-08-02 Fri	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:15	5.9	13%	105.0°
2030-08-03 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:10	5.96	21%	98.5°
2030-08-04 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:05	6.02	31%	91.6°
2030-08-05 Mon	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:00	6.07	41%	84.4°
2030-08-06 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 22:55	6.13	53%	77.4°
2030-08-07 Wed	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 22:55	6.19	64%	71.0°
2030-08-08 Thu	98	—	unknown	22:20–04:35 (good, 6.25 h)	87.1° 22:50	6.24	75%	65.4°
2030-08-09 Fri	90	—	unknown	22:20–04:40 (good, 6.33 h)	87.1° 22:45	6.3	84%	61.4°
2030-08-10 Sat	81	—	unknown	22:20–03:35 (good, 5.25 h)	87.1° 22:40	6.36	92%	59.2°
2030-08-11 Sun	57	—	unknown	22:15–04:40 (marginal, 6.42 h)	87.1° 22:40	6.41	97%	59.1°
2030-08-12 Mon	55	—	unknown	22:15–04:45 (marginal, 6.5 h)	87.1° 22:35	6.47	100%	61.1°
2030-08-13 Tue	58	—	unknown	22:15–23:00 (good, 0.75 h)	87.1° 22:30	6.53	100%	64.9°
2030-08-14 Wed	67	—	unknown	22:10–00:30 (good, 2.33 h)	87.1° 22:25	6.59	97%	70.0°
2030-08-15 Thu	74	—	unknown	22:10–01:40 (good, 3.5 h)	87.1° 22:20	6.64	92%	76.0°
2030-08-16 Fri	80	—	unknown	22:05–02:30 (good, 4.42 h)	87.1° 22:20	6.7	86%	82.3°
2030-08-17 Sat	85	—	unknown	22:05–03:20 (good, 5.25 h)	87.1° 22:15	6.76	78%	88.8°
2030-08-18 Sun	100	—	unknown	22:05–03:45 (good, 5.67 h)	87.1° 22:10	6.82	70%	95.2°
2030-08-19 Mon	100	—	unknown	22:00–03:50 (good, 5.83 h)	87.1° 22:05	6.87	61%	101.3°
2030-08-20 Tue	100	—	unknown	22:00–03:50 (good, 5.83 h)	87.1° 22:00	6.93	51%	106.9°
2030-08-21 Wed	100	—	unknown	21:55–03:50 (good, 5.92 h)	87.1° 22:00	6.99	42%	111.9°
2030-08-22 Thu	100	—	unknown	21:55–03:50 (good, 5.92 h)	87.1° 21:55	7.05	33%	116.0°
2030-08-23 Fri	100	—	unknown	21:55–03:45 (good, 5.83 h)	87.1° 21:50	7.1	24%	119.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-25&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.