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: 07-22 (100), 07-23 (100), 07-24 (100), 07-25 (100), 07-26 (100) — by astronomy; check the weather when the night is within four days.

2030-07-22astronomy score per night — click a bar for that night2030-08-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-07-22 Mon	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.32	44%	86.4°
2030-07-23 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:15	5.37	35%	95.7°
2030-07-24 Wed	100	—	unknown	22:50–04:15 (good, 5.42 h)	71.1° 01:10	5.42	26%	105.0°
2030-07-25 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.48	18%	113.9°
2030-07-26 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.53	12%	122.5°
2030-07-27 Sat	100	—	unknown	22:45–04:20 (good, 5.58 h)	71.1° 01:00	5.58	6%	130.2°
2030-07-28 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.63	2%	136.6°
2030-07-29 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.69	0%	140.8°
2030-07-30 Tue	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:50	5.74	0%	141.9°
2030-07-31 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.79	2%	139.5°
2030-08-01 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.85	7%	134.0°
2030-08-02 Fri	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:35	5.9	13%	126.3°
2030-08-03 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.96	21%	117.0°
2030-08-04 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.02	31%	106.8°
2030-08-05 Mon	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:25	6.07	41%	96.0°
2030-08-06 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.13	53%	85.0°
2030-08-07 Wed	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:15	6.19	64%	73.9°
2030-08-08 Thu	100	—	unknown	22:20–04:35 (good, 6.25 h)	71.1° 00:15	6.24	75%	63.2°
2030-08-09 Fri	95	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:10	6.3	84%	53.3°
2030-08-10 Sat	86	—	unknown	03:55–04:40 (good, 0.75 h)	71.1° 00:05	6.36	92%	45.0°
2030-08-11 Sun	43	—	unknown	22:15–04:40 (marginal, 6.42 h)	71.1° 00:00	6.41	97%	39.5°
2030-08-12 Mon	37	—	unknown	22:15–04:45 (marginal, 6.5 h)	71.1° 00:00	6.47	100%	38.1°
2030-08-13 Tue	39	—	unknown	22:15–04:45 (marginal, 6.5 h)	71.1° 23:55	6.53	100%	40.9°
2030-08-14 Wed	48	—	unknown	22:10–04:45 (marginal, 6.58 h)	71.1° 23:50	6.59	97%	47.1°
2030-08-15 Thu	62	—	unknown	22:10–23:20 (good, 1.17 h)	71.1° 23:45	6.64	92%	55.2°
2030-08-16 Fri	74	—	unknown	22:05–01:35 (good, 3.5 h)	71.1° 23:40	6.7	86%	64.2°
2030-08-17 Sat	81	—	unknown	22:05–02:50 (good, 4.75 h)	71.1° 23:40	6.76	78%	73.7°
2030-08-18 Sun	100	—	unknown	22:05–03:55 (good, 5.83 h)	71.1° 23:35	6.82	70%	83.3°
2030-08-19 Mon	100	—	unknown	22:00–04:15 (good, 6.25 h)	71.1° 23:30	6.87	61%	92.8°
2030-08-20 Tue	100	—	unknown	22:00–04:20 (good, 6.33 h)	71.1° 23:25	6.93	51%	102.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-22&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.