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: 05-23 (100), 05-24 (100), 05-25 (100), 05-26 (100), 05-27 (100) — by astronomy; check the weather when the night is within four days.

2036-05-18astronomy score per night — click a bar for that night2036-06-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-05-18 Sun	81	—	unknown	00:35–04:00 (good, 3.42 h)	71.1° 05:35	5.39	45%	49.3°
2036-05-19 Mon	90	—	unknown	00:30–04:00 (good, 3.5 h)	71.1° 05:30	5.34	35%	56.2°
2036-05-20 Tue	95	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:25	5.29	26%	64.3°
2036-05-21 Wed	97	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.24	18%	73.3°
2036-05-22 Thu	99	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:20	5.19	10%	83.1°
2036-05-23 Fri	100	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:15	5.15	5%	93.3°
2036-05-24 Sat	100	—	unknown	00:10–03:55 (good, 3.75 h)	71.1° 05:10	5.1	1%	103.7°
2036-05-25 Sun	100	—	unknown	00:05–03:50 (good, 3.75 h)	71.1° 05:05	5.06	0%	113.9°
2036-05-26 Mon	100	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:00	5.01	2%	123.5°
2036-05-27 Tue	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 05:00	4.97	6%	131.6°
2036-05-28 Wed	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 04:55	4.93	13%	137.1°
2036-05-29 Thu	100	—	unknown	23:50–03:50 (good, 4.0 h)	71.1° 04:50	4.89	22%	139.0°
2036-05-30 Fri	100	—	unknown	23:50–03:45 (good, 3.92 h)	71.1° 04:45	4.85	33%	136.7°
2036-05-31 Sat	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.81	44%	131.0°
2036-06-01 Sun	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:40	4.78	55%	123.2°
2036-06-02 Mon	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:35	4.74	66%	114.1°
2036-06-03 Tue	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:30	4.71	76%	104.4°
2036-06-04 Wed	80	—	unknown	23:50–03:40 (good, 3.83 h)	71.1° 04:25	4.68	84%	94.6°
2036-06-05 Thu	68	—	unknown	00:25–03:40 (good, 3.25 h)	71.1° 04:25	4.65	91%	84.7°
2036-06-06 Fri	57	—	unknown	01:20–03:40 (good, 2.33 h)	71.1° 04:20	4.62	96%	75.2°
2036-06-07 Sat	47	—	unknown	02:10–03:40 (good, 1.5 h)	71.1° 04:15	4.59	99%	66.1°
2036-06-08 Sun	40	—	unknown	23:05–03:40 (marginal, 4.58 h)	71.1° 04:10	4.57	100%	57.9°
2036-06-09 Mon	35	—	unknown	23:05–03:40 (marginal, 4.58 h)	71.1° 04:05	4.54	99%	50.7°
2036-06-10 Tue	34	—	unknown	23:05–03:40 (marginal, 4.58 h)	71.1° 04:05	4.52	96%	45.2°
2036-06-11 Wed	38	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 04:00	4.5	91%	41.9°
2036-06-12 Thu	66	—	unknown	23:10–23:45 (good, 0.58 h)	71.1° 03:55	4.49	85%	41.2°
2036-06-13 Fri	79	—	unknown	23:10–03:30 (good, 4.33 h)	71.1° 03:50	4.47	78%	43.3°
2036-06-14 Sat	92	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:50	4.46	70%	47.7°
2036-06-15 Sun	96	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.45	61%	54.0°
2036-06-16 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.44	51%	61.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-05-18&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.