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 HD 189733: 05-23 (100), 05-24 (100), 05-25 (100), 05-26 (100), 05-27 (100) — by astronomy; check the weather when the night is within four days.

2047-05-12astronomy score per night — click a bar for that night2047-06-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-05-12 Sun	34	—	unknown	03:45–04:10 (good, 0.42 h)	71.2° 06:00	5.74	86%	52.5°
2047-05-13 Mon	37	—	unknown	03:00–04:10 (good, 1.17 h)	71.1° 05:55	5.69	78%	45.4°
2047-05-14 Tue	54	—	unknown	00:50–04:10 (good, 3.33 h)	71.1° 05:55	5.64	68%	41.1°
2047-05-15 Wed	62	—	unknown	00:45–04:05 (good, 3.33 h)	71.1° 05:50	5.58	58%	40.2°
2047-05-16 Thu	71	—	unknown	00:45–04:05 (good, 3.33 h)	71.2° 05:45	5.53	48%	42.7°
2047-05-17 Fri	80	—	unknown	00:40–04:05 (good, 3.42 h)	71.2° 05:40	5.48	38%	47.6°
2047-05-18 Sat	86	—	unknown	00:35–04:05 (good, 3.5 h)	71.1° 05:35	5.42	29%	54.3°
2047-05-19 Sun	90	—	unknown	00:30–04:00 (good, 3.5 h)	71.1° 05:35	5.37	21%	62.1°
2047-05-20 Mon	95	—	unknown	00:30–04:00 (good, 3.5 h)	71.2° 05:30	5.32	14%	70.4°
2047-05-21 Tue	98	—	unknown	00:25–04:00 (good, 3.58 h)	71.2° 05:25	5.27	8%	79.2°
2047-05-22 Wed	98	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.23	4%	88.2°
2047-05-23 Thu	100	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:15	5.18	1%	97.3°
2047-05-24 Fri	100	—	unknown	00:10–03:55 (good, 3.75 h)	71.1° 05:15	5.13	0%	106.3°
2047-05-25 Sat	100	—	unknown	00:10–03:55 (good, 3.75 h)	71.2° 05:10	5.09	1%	115.1°
2047-05-26 Sun	100	—	unknown	00:05–03:50 (good, 3.75 h)	71.2° 05:05	5.04	4%	123.4°
2047-05-27 Mon	100	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:00	5.0	9%	130.7°
2047-05-28 Tue	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 05:00	4.96	16%	136.4°
2047-05-29 Wed	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 04:55	4.91	24%	139.6°
2047-05-30 Thu	100	—	unknown	23:50–03:45 (good, 3.92 h)	71.2° 04:50	4.87	33%	139.5°
2047-05-31 Fri	100	—	unknown	23:50–03:45 (good, 3.92 h)	71.2° 04:45	4.84	44%	135.9°
2047-06-01 Sat	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:40	4.8	55%	129.3°
2047-06-02 Sun	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:40	4.76	66%	120.7°
2047-06-03 Mon	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.2° 04:35	4.73	77%	110.6°
2047-06-04 Tue	100	—	unknown	23:50–03:45 (good, 3.92 h)	71.2° 04:30	4.7	86%	99.7°
2047-06-05 Wed	74	—	unknown	00:00–03:40 (good, 3.67 h)	71.1° 04:25	4.67	93%	88.3°
2047-06-06 Thu	61	—	unknown	00:50–03:40 (good, 2.83 h)	71.1° 04:20	4.64	98%	77.0°
2047-06-07 Fri	49	—	unknown	01:50–03:40 (good, 1.83 h)	71.1° 04:20	4.61	100%	66.1°
2047-06-08 Sat	42	—	unknown	23:05–03:40 (marginal, 4.58 h)	71.2° 04:15	4.58	99%	56.1°
2047-06-09 Sun	38	—	unknown	23:05–03:40 (marginal, 4.58 h)	71.2° 04:10	4.56	95%	47.9°
2047-06-10 Mon	50	—	unknown	23:05–23:20 (good, 0.25 h)	71.1° 04:05	4.54	90%	42.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-05-12&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.