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: 08-10 (100), 08-11 (100), 08-12 (100), 08-13 (100), 08-14 (100) — by astronomy; check the weather when the night is within four days.

2028-08-06astronomy score per night — click a bar for that night2028-09-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-08-06 Sun	46	—	unknown	22:25–04:35 (marginal, 6.17 h)	71.1° 00:20	6.16	98%	44.3°
2028-08-07 Mon	55	—	unknown	22:25–22:55 (good, 0.5 h)	71.1° 00:15	6.21	94%	49.6°
2028-08-08 Tue	69	—	unknown	22:20–00:20 (good, 2.0 h)	71.1° 00:10	6.27	88%	56.4°
2028-08-09 Wed	76	—	unknown	22:20–02:20 (good, 4.0 h)	71.1° 00:05	6.33	82%	64.2°
2028-08-10 Thu	100	—	unknown	22:15–03:25 (good, 5.17 h)	71.1° 00:05	6.38	74%	72.7°
2028-08-11 Fri	100	—	unknown	22:15–04:30 (good, 6.25 h)	71.1° 00:00	6.44	65%	81.6°
2028-08-12 Sat	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 23:55	6.5	56%	90.9°
2028-08-13 Sun	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:50	6.56	46%	100.3°
2028-08-14 Mon	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:50	6.61	35%	109.8°
2028-08-15 Tue	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:45	6.67	26%	119.0°
2028-08-16 Wed	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:40	6.73	16%	127.6°
2028-08-17 Thu	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.79	9%	134.6°
2028-08-18 Fri	100	—	unknown	22:00–04:40 (good, 6.67 h)	71.1° 23:30	6.84	3%	138.8°
2028-08-19 Sat	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.9	0%	138.9°
2028-08-20 Sun	100	—	unknown	22:00–04:30 (good, 6.5 h)	71.1° 23:25	6.96	0%	134.6°
2028-08-21 Mon	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:20	7.02	4%	127.0°
2028-08-22 Tue	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:15	7.07	9%	117.5°
2028-08-23 Wed	100	—	unknown	21:50–04:20 (good, 6.5 h)	71.1° 23:10	7.13	17%	107.0°
2028-08-24 Thu	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.19	27%	96.2°
2028-08-25 Fri	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.25	38%	85.6°
2028-08-26 Sat	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.3	49%	75.4°
2028-08-27 Sun	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 22:55	7.36	59%	65.9°
2028-08-28 Mon	98	—	unknown	21:40–04:00 (good, 6.33 h)	71.1° 22:55	7.42	69%	57.2°
2028-08-29 Tue	91	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.47	78%	49.9°
2028-08-30 Wed	82	—	unknown	03:05–03:50 (good, 0.75 h)	71.1° 22:45	7.53	86%	44.3°
2028-08-31 Thu	46	—	unknown	21:35–04:15 (marginal, 6.67 h)	71.1° 22:40	7.58	92%	41.1°
2028-09-01 Fri	39	—	unknown	21:35–03:55 (marginal, 6.33 h)	71.1° 22:35	7.64	96%	40.8°
2028-09-02 Sat	37	—	unknown	21:30–03:40 (marginal, 6.17 h)	71.1° 22:35	7.7	99%	43.2°
2028-09-03 Sun	40	—	unknown	21:30–03:30 (marginal, 6.0 h)	71.1° 22:30	7.75	100%	48.0°
2028-09-04 Mon	46	—	unknown	21:30–03:25 (marginal, 5.92 h)	71.1° 22:25	7.81	99%	54.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-08-06&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.