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: 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100) — by astronomy; check the weather when the night is within four days.

2031-08-17astronomy score per night — click a bar for that night2031-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-08-17 Sun	100	—	unknown	22:05–04:15 (good, 6.17 h)	87.1° 22:15	6.75	0%	117.1°
2031-08-18 Mon	100	—	unknown	22:05–04:10 (good, 6.08 h)	87.1° 22:10	6.8	1%	112.7°
2031-08-19 Tue	100	—	unknown	22:00–04:05 (good, 6.08 h)	87.1° 22:05	6.86	3%	107.3°
2031-08-20 Wed	100	—	unknown	22:00–04:05 (good, 6.08 h)	87.1° 22:05	6.92	7%	101.2°
2031-08-21 Thu	100	—	unknown	22:00–04:00 (good, 6.0 h)	87.1° 22:00	6.98	14%	94.6°
2031-08-22 Fri	100	—	unknown	21:55–03:55 (good, 6.0 h)	87.1° 21:55	7.03	21%	87.8°
2031-08-23 Sat	100	—	unknown	21:55–03:50 (good, 5.92 h)	87.1° 21:50	7.09	30%	80.8°
2031-08-24 Sun	100	—	unknown	21:50–03:45 (good, 5.92 h)	87.1° 21:50	7.15	41%	74.1°
2031-08-25 Mon	100	—	unknown	21:50–03:45 (good, 5.92 h)	87.1° 21:45	7.2	52%	68.0°
2031-08-26 Tue	96	—	unknown	21:50–03:40 (good, 5.83 h)	87.1° 21:40	7.26	63%	62.8°
2031-08-27 Wed	88	—	unknown	21:45–03:35 (good, 5.83 h)	87.1° 21:35	7.32	74%	59.2°
2031-08-28 Thu	79	—	unknown	21:45–03:30 (good, 5.75 h)	87.1° 21:30	7.37	83%	57.6°
2031-08-29 Fri	55	—	unknown	21:40–03:55 (marginal, 6.25 h)	87.1° 21:30	7.43	91%	58.4°
2031-08-30 Sat	51	—	unknown	21:40–03:45 (marginal, 6.08 h)	87.1° 21:25	7.49	97%	61.5°
2031-08-31 Sun	52	—	unknown	21:40–22:10 (good, 0.5 h)	87.1° 21:20	7.54	100%	66.4°
2031-09-01 Mon	60	—	unknown	21:35–23:45 (good, 2.17 h)	87.1° 21:15	7.6	99%	72.8°
2031-09-02 Tue	70	—	unknown	21:35–00:40 (good, 3.08 h)	87.1° 21:10	7.66	97%	79.9°
2031-09-03 Wed	80	—	unknown	21:30–01:30 (good, 4.0 h)	87.1° 21:10	7.71	92%	87.2°
2031-09-04 Thu	85	—	unknown	21:30–02:25 (good, 4.92 h)	87.1° 21:05	7.77	84%	94.5°
2031-09-05 Fri	100	—	unknown	21:30–02:35 (good, 5.08 h)	87.1° 21:00	7.82	76%	101.4°
2031-09-06 Sat	100	—	unknown	21:25–02:40 (good, 5.25 h)	87.1° 20:55	7.88	67%	107.6°
2031-09-07 Sun	100	—	unknown	21:25–02:40 (good, 5.25 h)	87.1° 20:55	7.93	57%	113.0°
2031-09-08 Mon	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:50	7.99	48%	117.4°
2031-09-09 Tue	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:45	8.04	38%	120.5°
2031-09-10 Wed	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:40	8.09	29%	122.2°
2031-09-11 Thu	100	—	unknown	21:15–02:35 (good, 5.33 h)	87.1° 20:35	8.15	21%	122.4°
2031-09-12 Fri	100	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:35	8.2	14%	121.0°
2031-09-13 Sat	100	—	unknown	21:10–02:30 (good, 5.33 h)	87.1° 20:30	8.26	8%	118.2°
2031-09-14 Sun	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:25	8.31	4%	114.1°
2031-09-15 Mon	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:20	8.36	1%	108.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-08-17&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.