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: 08-17 (100), 08-18 (100), 08-29 (100), 08-30 (100), 08-31 (100) — by astronomy; check the weather when the night is within four days.

2029-08-17astronomy score per night — click a bar for that night2029-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-08-17 Fri	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:35	6.77	63%	68.8°
2029-08-18 Sat	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.83	73%	59.0°
2029-08-19 Sun	92	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.89	82%	50.5°
2029-08-20 Mon	83	—	unknown	03:35–04:30 (good, 0.92 h)	71.1° 23:25	6.95	90%	43.8°
2029-08-21 Tue	44	—	unknown	21:55–04:55 (marginal, 7.0 h)	71.1° 23:20	7.0	95%	39.9°
2029-08-22 Wed	38	—	unknown	21:55–04:30 (marginal, 6.58 h)	71.1° 23:15	7.06	98%	39.3°
2029-08-23 Thu	38	—	unknown	21:55–04:20 (marginal, 6.42 h)	71.1° 23:15	7.12	100%	42.2°
2029-08-24 Fri	44	—	unknown	21:50–04:10 (marginal, 6.33 h)	71.1° 23:10	7.17	99%	47.7°
2029-08-25 Sat	53	—	unknown	21:50–22:15 (good, 0.42 h)	71.1° 23:05	7.23	96%	54.8°
2029-08-26 Sun	67	—	unknown	21:45–23:50 (good, 2.08 h)	71.1° 23:00	7.29	92%	63.0°
2029-08-27 Mon	76	—	unknown	21:45–01:30 (good, 3.75 h)	71.1° 23:00	7.35	86%	71.7°
2029-08-28 Tue	82	—	unknown	21:45–02:35 (good, 4.83 h)	71.1° 22:55	7.4	79%	80.7°
2029-08-29 Wed	100	—	unknown	21:40–03:30 (good, 5.83 h)	71.1° 22:50	7.46	71%	89.9°
2029-08-30 Thu	100	—	unknown	21:40–03:35 (good, 5.92 h)	71.1° 22:45	7.51	62%	99.1°
2029-08-31 Fri	100	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:40	7.57	52%	108.2°
2029-09-01 Sat	100	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:40	7.63	43%	117.0°
2029-09-02 Sun	100	—	unknown	21:35–03:35 (good, 6.0 h)	71.1° 22:35	7.68	33%	125.4°
2029-09-03 Mon	100	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:30	7.74	24%	132.8°
2029-09-04 Tue	100	—	unknown	21:30–03:30 (good, 6.0 h)	71.1° 22:25	7.79	16%	138.4°
2029-09-05 Wed	100	—	unknown	21:25–03:30 (good, 6.08 h)	71.1° 22:20	7.85	8%	140.9°
2029-09-06 Thu	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.9	3%	139.4°
2029-09-07 Fri	100	—	unknown	21:25–03:20 (good, 5.92 h)	71.1° 22:15	7.96	0%	134.1°
2029-09-08 Sat	100	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:10	8.01	0%	125.8°
2029-09-09 Sun	100	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:05	8.07	3%	115.7°
2029-09-10 Mon	100	—	unknown	21:15–03:10 (good, 5.92 h)	71.1° 22:05	8.12	9%	104.7°
2029-09-11 Tue	100	—	unknown	21:15–03:05 (good, 5.83 h)	71.1° 22:00	8.17	17%	93.3°
2029-09-12 Wed	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.1° 21:55	8.23	27%	82.0°
2029-09-13 Thu	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:50	8.28	37%	71.1°
2029-09-14 Fri	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:45	8.33	48%	61.0°
2029-09-15 Sat	94	—	unknown	21:05–02:50 (good, 5.75 h)	71.1° 21:45	8.39	60%	52.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-08-17&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.