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: 08-23 (100), 08-24 (100), 09-03 (100), 09-04 (100), 09-05 (100) — by astronomy; check the weather when the night is within four days.

2042-08-23astronomy score per night — click a bar for that night2042-09-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-08-23 Sat	100	—	unknown	21:55–03:50 (good, 5.92 h)	87.1° 21:50	7.11	50%	73.4°
2042-08-24 Sun	100	—	unknown	21:50–03:45 (good, 5.92 h)	87.1° 21:45	7.17	60%	70.3°
2042-08-25 Mon	97	—	unknown	21:50–03:40 (good, 5.83 h)	87.1° 21:45	7.22	70%	68.1°
2042-08-26 Tue	89	—	unknown	21:45–03:40 (good, 5.92 h)	87.1° 21:40	7.28	79%	67.0°
2042-08-27 Wed	81	—	unknown	21:45–03:35 (good, 5.83 h)	87.1° 21:35	7.34	87%	67.1°
2042-08-28 Thu	67	—	unknown	21:45–01:50 (good, 4.08 h)	87.1° 21:30	7.39	94%	68.6°
2042-08-29 Fri	66	—	unknown	21:40–00:50 (good, 3.17 h)	87.1° 21:25	7.45	98%	71.5°
2042-08-30 Sat	67	—	unknown	21:40–00:40 (good, 3.0 h)	87.1° 21:25	7.51	100%	75.6°
2042-08-31 Sun	74	—	unknown	21:35–01:00 (good, 3.42 h)	87.1° 21:20	7.56	99%	80.7°
2042-09-01 Mon	79	—	unknown	21:35–01:30 (good, 3.92 h)	87.1° 21:15	7.62	95%	86.3°
2042-09-02 Tue	83	—	unknown	21:35–02:10 (good, 4.58 h)	87.1° 21:10	7.67	88%	92.2°
2042-09-03 Wed	100	—	unknown	21:30–02:40 (good, 5.17 h)	87.1° 21:05	7.73	80%	97.8°
2042-09-04 Thu	100	—	unknown	21:30–02:45 (good, 5.25 h)	87.1° 21:05	7.78	70%	102.9°
2042-09-05 Fri	100	—	unknown	21:25–02:45 (good, 5.33 h)	87.1° 21:00	7.84	59%	107.2°
2042-09-06 Sat	100	—	unknown	21:25–02:45 (good, 5.33 h)	87.1° 20:55	7.89	48%	110.3°
2042-09-07 Sun	100	—	unknown	21:25–02:45 (good, 5.33 h)	87.1° 20:50	7.95	37%	112.3°
2042-09-08 Mon	100	—	unknown	21:20–02:45 (good, 5.42 h)	87.1° 20:50	8.0	27%	113.1°
2042-09-09 Tue	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:45	8.06	18%	112.5°
2042-09-10 Wed	100	—	unknown	21:15–02:40 (good, 5.42 h)	87.1° 20:40	8.11	11%	110.8°
2042-09-11 Thu	100	—	unknown	21:15–02:35 (good, 5.33 h)	87.1° 20:35	8.17	6%	108.2°
2042-09-12 Fri	100	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:30	8.22	2%	104.7°
2042-09-13 Sat	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:30	8.27	0%	100.7°
2042-09-14 Sun	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:25	8.33	0%	96.4°
2042-09-15 Mon	100	—	unknown	21:05–02:20 (good, 5.25 h)	87.1° 20:20	8.38	2%	91.8°
2042-09-16 Tue	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.43	6%	87.2°
2042-09-17 Wed	100	—	unknown	21:05–02:10 (good, 5.08 h)	87.1° 20:10	8.48	11%	82.7°
2042-09-18 Thu	100	—	unknown	21:00–02:10 (good, 5.17 h)	87.1° 20:10	8.54	18%	78.4°
2042-09-19 Fri	100	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.59	25%	74.6°
2042-09-20 Sat	100	—	unknown	21:00–02:00 (good, 5.0 h)	87.1° 20:00	8.64	34%	71.4°
2042-09-21 Sun	99	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.69	44%	68.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-08-23&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.