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: 06-23 (100), 06-24 (100), 06-25 (100), 06-26 (100), 06-27 (100) — by astronomy; check the weather when the night is within four days.

2030-06-20astronomy score per night — click a bar for that night2030-07-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-06-20 Thu	87	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:25	4.42	68%	45.3°
2030-06-21 Fri	94	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	58%	52.8°
2030-06-22 Sat	98	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	48%	61.3°
2030-06-23 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	38%	70.4°
2030-06-24 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	29%	79.7°
2030-06-25 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.44	21%	89.0°
2030-06-26 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.46	14%	98.3°
2030-06-27 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.47	8%	107.5°
2030-06-28 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	4%	116.4°
2030-06-29 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	1%	124.7°
2030-06-30 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.52	0%	132.1°
2030-07-01 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.54	1%	138.0°
2030-07-02 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.56	4%	141.5°
2030-07-03 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.58	9%	141.7°
2030-07-04 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.61	16%	138.6°
2030-07-05 Fri	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.64	24%	132.5°
2030-07-06 Sat	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.67	34%	124.4°
2030-07-07 Sun	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:20	4.7	44%	114.9°
2030-07-08 Mon	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:15	4.73	55%	104.5°
2030-07-09 Tue	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:10	4.77	66%	93.5°
2030-07-10 Wed	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.8	77%	82.1°
2030-07-11 Thu	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.84	86%	70.8°
2030-07-12 Fri	71	—	unknown	23:50–03:55 (good, 4.08 h)	71.1° 02:00	4.88	93%	59.9°
2030-07-13 Sat	51	—	unknown	03:20–03:55 (good, 0.58 h)	71.1° 01:55	4.92	98%	50.1°
2030-07-14 Sun	38	—	unknown	23:00–04:00 (marginal, 5.0 h)	71.1° 01:50	4.96	100%	42.5°
2030-07-15 Mon	34	—	unknown	23:00–04:00 (marginal, 5.0 h)	71.1° 01:50	5.0	99%	38.4°
2030-07-16 Tue	38	—	unknown	23:00–04:00 (marginal, 5.0 h)	71.1° 01:45	5.04	95%	38.7°
2030-07-17 Wed	49	—	unknown	22:55–23:15 (good, 0.33 h)	71.1° 01:40	5.09	89%	43.0°
2030-07-18 Thu	64	—	unknown	22:55–01:30 (good, 2.58 h)	71.1° 01:35	5.13	82%	50.0°
2030-07-19 Fri	96	—	unknown	22:55–03:55 (good, 5.0 h)	71.1° 01:30	5.18	73%	58.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-06-20&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.