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: 03-19 (97), 03-18 (96), 03-20 (96), 03-16 (95), 03-15 (94) — by astronomy; check the weather when the night is within four days.

2040-02-20astronomy score per night — click a bar for that night2040-03-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-02-20 Mon	66	—	unknown	03:00–05:40 (good, 2.67 h)	87.1° 08:55	10.06	60%	113.3°
2040-02-21 Tue	66	—	unknown	03:05–05:35 (good, 2.5 h)	87.1° 08:50	10.02	69%	115.0°
2040-02-22 Wed	66	—	unknown	03:05–05:35 (good, 2.5 h)	87.1° 08:50	9.97	77%	115.6°
2040-02-23 Thu	64	—	unknown	03:00–05:35 (good, 2.58 h)	87.1° 08:45	9.93	84%	115.0°
2040-02-24 Fri	57	—	unknown	03:00–05:35 (good, 2.58 h)	87.1° 08:40	9.89	91%	113.3°
2040-02-25 Sat	53	—	unknown	03:00–05:30 (good, 2.5 h)	87.1° 08:35	9.84	96%	110.5°
2040-02-26 Sun	50	—	unknown	03:05–05:30 (good, 2.42 h)	87.1° 08:30	9.8	99%	106.7°
2040-02-27 Mon	47	—	unknown	03:05–05:30 (good, 2.42 h)	87.1° 08:30	9.75	100%	102.2°
2040-02-28 Tue	42	—	unknown	03:25–05:25 (good, 2.0 h)	87.1° 08:25	9.71	99%	97.1°
2040-02-29 Wed	40	—	unknown	03:45–05:25 (good, 1.67 h)	87.1° 08:20	9.66	96%	91.5°
2040-03-01 Thu	39	—	unknown	03:50–05:25 (good, 1.58 h)	87.1° 08:15	9.62	91%	85.9°
2040-03-02 Fri	40	—	unknown	03:40–05:20 (good, 1.67 h)	87.1° 08:15	9.57	84%	80.3°
2040-03-03 Sat	42	—	unknown	03:05–05:20 (good, 2.25 h)	87.1° 08:10	9.53	75%	75.2°
2040-03-04 Sun	47	—	unknown	02:35–05:20 (good, 2.75 h)	87.1° 08:05	9.48	65%	70.7°
2040-03-05 Mon	54	—	unknown	02:25–05:15 (good, 2.83 h)	87.1° 08:00	9.43	54%	67.2°
2040-03-06 Tue	64	—	unknown	02:05–05:15 (good, 3.17 h)	87.1° 07:55	9.39	43%	65.1°
2040-03-07 Wed	74	—	unknown	02:00–05:15 (good, 3.25 h)	87.1° 07:55	9.34	32%	64.6°
2040-03-08 Thu	83	—	unknown	01:55–05:10 (good, 3.25 h)	87.1° 07:50	9.29	22%	65.7°
2040-03-09 Fri	87	—	unknown	01:50–05:10 (good, 3.33 h)	87.1° 07:45	9.24	13%	68.4°
2040-03-10 Sat	89	—	unknown	01:45–05:10 (good, 3.42 h)	87.1° 07:40	9.19	6%	72.5°
2040-03-11 Sun	89	—	unknown	01:45–05:05 (good, 3.33 h)	87.1° 07:35	9.15	2%	77.5°
2040-03-12 Mon	91	—	unknown	01:40–05:05 (good, 3.42 h)	87.1° 07:35	9.1	0%	83.2°
2040-03-13 Tue	91	—	unknown	01:35–05:05 (good, 3.5 h)	87.1° 07:30	9.05	1%	89.1°
2040-03-14 Wed	92	—	unknown	01:30–05:00 (good, 3.5 h)	87.1° 07:25	9.0	4%	94.8°
2040-03-15 Thu	94	—	unknown	01:25–05:00 (good, 3.58 h)	87.1° 07:20	8.95	10%	100.2°
2040-03-16 Fri	95	—	unknown	01:25–05:00 (good, 3.58 h)	87.1° 07:20	8.9	16%	105.1°
2040-03-17 Sat	94	—	unknown	01:20–04:55 (good, 3.58 h)	87.1° 07:15	8.84	24%	109.1°
2040-03-18 Sun	96	—	unknown	01:15–04:55 (good, 3.67 h)	87.1° 07:10	8.79	33%	112.2°
2040-03-19 Mon	97	—	unknown	01:15–04:55 (good, 3.67 h)	87.1° 07:05	8.74	42%	114.3°
2040-03-20 Tue	96	—	unknown	01:15–04:50 (good, 3.58 h)	87.1° 07:00	8.69	52%	115.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-02-20&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.