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: 06-18 (100), 06-19 (100), 06-20 (100), 06-21 (100), 06-22 (100) — by astronomy; check the weather when the night is within four days.

2042-06-18astronomy score per night — click a bar for that night2042-07-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-06-18 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	2%	127.0°
2042-06-19 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:30	4.42	6%	131.2°
2042-06-20 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:25	4.42	11%	132.9°
2042-06-21 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	18%	132.0°
2042-06-22 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	26%	128.7°
2042-06-23 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	36%	123.7°
2042-06-24 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	45%	117.4°
2042-06-25 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.44	54%	110.3°
2042-06-26 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.46	64%	102.7°
2042-06-27 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.47	72%	94.7°
2042-06-28 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	81%	86.4°
2042-06-29 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	88%	78.2°
2042-06-30 Mon	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 02:45	4.52	94%	70.0°
2042-07-01 Tue	63	—	unknown	00:15–03:45 (good, 3.5 h)	71.1° 02:45	4.54	98%	62.3°
2042-07-02 Wed	53	—	unknown	02:20–03:45 (good, 1.42 h)	71.1° 02:40	4.56	100%	55.5°
2042-07-03 Thu	46	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 02:35	4.59	99%	50.3°
2042-07-04 Fri	47	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 02:30	4.61	97%	47.4°
2042-07-05 Sat	54	—	unknown	23:10–01:10 (good, 2.0 h)	71.1° 02:25	4.64	92%	47.4°
2042-07-06 Sun	90	—	unknown	23:10–02:45 (good, 3.58 h)	71.1° 02:25	4.67	84%	50.5°
2042-07-07 Mon	97	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:20	4.7	75%	56.2°
2042-07-08 Tue	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:15	4.73	65%	63.7°
2042-07-09 Wed	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:10	4.77	54%	72.4°
2042-07-10 Thu	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:10	4.8	42%	81.8°
2042-07-11 Fri	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.84	31%	91.3°
2042-07-12 Sat	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:00	4.88	21%	100.8°
2042-07-13 Sun	100	—	unknown	23:00–03:55 (good, 4.92 h)	71.1° 01:55	4.92	13%	109.9°
2042-07-14 Mon	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	4.96	6%	118.1°
2042-07-15 Tue	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	5.0	2%	125.0°
2042-07-16 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.05	0%	130.1°
2042-07-17 Thu	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:40	5.09	1%	132.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-06-18&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.