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: 05-31 (100), 06-01 (100), 06-02 (100), 06-03 (100), 06-04 (100) — by astronomy; check the weather when the night is within four days.

2035-05-26astronomy score per night — click a bar for that night2035-06-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-05-26 Sat	41	—	unknown	00:05–00:10 (good, 0.08 h)	71.1° 05:05	5.05	81%	40.1°
2035-05-27 Sun	62	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:00	5.0	73%	39.6°
2035-05-28 Mon	75	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 05:00	4.96	64%	42.1°
2035-05-29 Tue	86	—	unknown	23:50–03:50 (good, 4.0 h)	71.1° 04:55	4.92	54%	47.4°
2035-05-30 Wed	96	—	unknown	23:50–03:45 (good, 3.92 h)	71.1° 04:50	4.88	44%	54.7°
2035-05-31 Thu	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.84	33%	63.5°
2035-06-01 Fri	100	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:40	4.8	24%	73.4°
2035-06-02 Sat	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:40	4.77	15%	84.1°
2035-06-03 Sun	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:35	4.73	7%	95.3°
2035-06-04 Mon	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:30	4.7	2%	106.7°
2035-06-05 Tue	100	—	unknown	23:25–03:40 (good, 4.25 h)	71.1° 04:25	4.67	0%	117.7°
2035-06-06 Wed	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:20	4.64	1%	127.6°
2035-06-07 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:20	4.61	5%	135.4°
2035-06-08 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.59	12%	139.9°
2035-06-09 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:10	4.56	20%	140.0°
2035-06-10 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:05	4.54	30%	136.0°
2035-06-11 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.52	40%	129.3°
2035-06-12 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.5	51%	121.0°
2035-06-13 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:55	4.48	61%	112.0°
2035-06-14 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:50	4.47	71%	102.6°
2035-06-15 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.46	79%	93.2°
2035-06-16 Sat	80	—	unknown	23:35–03:40 (good, 4.08 h)	71.1° 03:45	4.44	87%	83.9°
2035-06-17 Sun	67	—	unknown	00:30–03:40 (good, 3.17 h)	71.1° 03:40	4.44	92%	74.7°
2035-06-18 Mon	55	—	unknown	01:25–03:40 (good, 2.25 h)	71.1° 03:35	4.43	97%	66.0°
2035-06-19 Tue	45	—	unknown	03:20–03:40 (good, 0.33 h)	71.1° 03:30	4.43	99%	57.8°
2035-06-20 Wed	38	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:25	4.42	100%	50.5°
2035-06-21 Thu	33	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:25	4.42	99%	44.6°
2035-06-22 Fri	34	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:20	4.42	96%	40.8°
2035-06-23 Sat	39	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:15	4.43	91%	39.6°
2035-06-24 Sun	70	—	unknown	23:15–23:25 (good, 0.17 h)	71.1° 03:10	4.43	85%	41.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-26&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.