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: 07-09 (100), 07-10 (100), 07-11 (100), 07-12 (100), 07-13 (100) — by astronomy; check the weather when the night is within four days.

2045-07-09astronomy score per night — click a bar for that night2045-08-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-07-09 Sun	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:10	4.78	26%	93.0°
2045-07-10 Mon	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.81	17%	102.8°
2045-07-11 Tue	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.85	9%	112.6°
2045-07-12 Wed	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:00	4.89	3%	121.8°
2045-07-13 Thu	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:55	4.93	0%	129.7°
2045-07-14 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	4.97	0%	135.1°
2045-07-15 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.02	3%	136.7°
2045-07-16 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.06	9%	134.3°
2045-07-17 Mon	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:40	5.1	17%	128.5°
2045-07-18 Tue	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.15	27%	120.5°
2045-07-19 Wed	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:30	5.2	38%	111.5°
2045-07-20 Thu	100	—	unknown	22:55–04:10 (good, 5.25 h)	71.1° 01:25	5.24	48%	102.0°
2045-07-21 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:25	5.29	59%	92.4°
2045-07-22 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.34	69%	83.0°
2045-07-23 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:15	5.39	78%	74.0°
2045-07-24 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.44	86%	65.5°
2045-07-25 Tue	98	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.49	92%	57.9°
2045-07-26 Wed	63	—	unknown	01:50–04:15 (good, 2.42 h)	71.1° 01:05	5.55	96%	51.4°
2045-07-27 Thu	50	—	unknown	22:40–04:20 (marginal, 5.67 h)	71.1° 01:00	5.6	99%	46.5°
2045-07-28 Fri	45	—	unknown	22:40–04:20 (marginal, 5.67 h)	71.1° 00:55	5.65	100%	43.7°
2045-07-29 Sat	45	—	unknown	22:40–04:20 (marginal, 5.67 h)	71.1° 00:50	5.71	99%	43.4°
2045-07-30 Sun	50	—	unknown	22:35–04:25 (marginal, 5.83 h)	71.1° 00:50	5.76	96%	45.7°
2045-07-31 Mon	59	—	unknown	22:35–23:45 (good, 1.17 h)	71.1° 00:45	5.81	92%	50.1°
2045-08-01 Tue	71	—	unknown	22:35–01:10 (good, 2.58 h)	71.1° 00:40	5.87	86%	56.2°
2045-08-02 Wed	98	—	unknown	22:30–03:00 (good, 4.5 h)	71.1° 00:35	5.93	79%	63.5°
2045-08-03 Thu	100	—	unknown	22:30–04:05 (good, 5.58 h)	71.1° 00:30	5.98	70%	71.7°
2045-08-04 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.04	61%	80.5°
2045-08-05 Sat	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:25	6.09	51%	89.7°
2045-08-06 Sun	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.15	40%	99.3°
2045-08-07 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:15	6.21	30%	108.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-07-09&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.