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: 07-24 (100), 07-25 (100), 07-26 (100), 07-27 (100), 07-28 (100) — by astronomy; check the weather when the night is within four days.

2046-07-20astronomy score per night — click a bar for that night2046-08-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-07-20 Fri	50	—	unknown	22:55–23:25 (good, 0.5 h)	71.1° 01:30	5.23	92%	44.6°
2046-07-21 Sat	62	—	unknown	22:50–00:50 (good, 2.0 h)	71.1° 01:25	5.28	86%	49.6°
2046-07-22 Sun	73	—	unknown	22:50–02:55 (good, 4.08 h)	71.1° 01:20	5.33	79%	56.1°
2046-07-23 Mon	98	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:15	5.38	70%	63.7°
2046-07-24 Tue	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:15	5.43	62%	71.9°
2046-07-25 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.48	52%	80.7°
2046-07-26 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.53	42%	89.7°
2046-07-27 Fri	100	—	unknown	22:45–04:20 (good, 5.58 h)	71.1° 01:00	5.59	33%	98.9°
2046-07-28 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.64	23%	108.2°
2046-07-29 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.69	15%	117.3°
2046-07-30 Mon	100	—	unknown	22:40–04:25 (good, 5.75 h)	71.1° 00:50	5.75	8%	125.7°
2046-07-31 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.8	3%	132.8°
2046-08-01 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.86	0%	137.4°
2046-08-02 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:35	5.91	0%	138.2°
2046-08-03 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.97	3%	135.0°
2046-08-04 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.02	9%	128.4°
2046-08-05 Sun	100	—	unknown	22:25–04:30 (good, 6.08 h)	71.1° 00:25	6.08	17%	119.6°
2046-08-06 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.14	27%	109.7°
2046-08-07 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.19	37%	99.3°
2046-08-08 Wed	100	—	unknown	22:20–04:35 (good, 6.25 h)	71.1° 00:15	6.25	49%	88.8°
2046-08-09 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:10	6.31	60%	78.6°
2046-08-10 Fri	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:05	6.36	70%	69.0°
2046-08-11 Sat	100	—	unknown	22:15–04:40 (good, 6.42 h)	71.1° 00:00	6.42	79%	60.1°
2046-08-12 Sun	93	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 00:00	6.48	87%	52.4°
2046-08-13 Mon	84	—	unknown	03:55–04:45 (good, 0.83 h)	71.1° 23:55	6.54	93%	46.3°
2046-08-14 Tue	48	—	unknown	22:10–04:45 (marginal, 6.58 h)	71.1° 23:50	6.59	97%	42.6°
2046-08-15 Wed	43	—	unknown	22:10–04:50 (marginal, 6.67 h)	71.1° 23:45	6.65	100%	41.6°
2046-08-16 Thu	43	—	unknown	22:05–04:50 (marginal, 6.75 h)	71.1° 23:40	6.71	100%	43.6°
2046-08-17 Fri	48	—	unknown	22:05–04:45 (marginal, 6.67 h)	71.1° 23:40	6.77	98%	47.9°
2046-08-18 Sat	57	—	unknown	22:05–22:45 (good, 0.67 h)	71.1° 23:35	6.82	95%	54.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-07-20&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.