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.

2038-05-31astronomy score per night — click a bar for that night2038-06-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-05-31 Mon	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.83	4%	99.1°
2038-06-01 Tue	100	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:40	4.79	1%	107.5°
2038-06-02 Wed	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:35	4.76	0%	115.5°
2038-06-03 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:35	4.72	1%	122.8°
2038-06-04 Fri	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:30	4.69	4%	129.0°
2038-06-05 Sat	100	—	unknown	23:25–03:40 (good, 4.25 h)	71.1° 04:25	4.66	8%	133.5°
2038-06-06 Sun	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:20	4.63	15%	135.5°
2038-06-07 Mon	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:15	4.6	23%	134.5°
2038-06-08 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.58	33%	130.5°
2038-06-09 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:10	4.55	44%	124.2°
2038-06-10 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:05	4.53	55%	116.0°
2038-06-11 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:00	4.51	66%	106.7°
2038-06-12 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:00	4.49	77%	96.7°
2038-06-13 Sun	80	—	unknown	23:40–03:40 (good, 4.0 h)	71.1° 03:55	4.48	86%	86.3°
2038-06-14 Mon	66	—	unknown	00:35–03:40 (good, 3.08 h)	71.1° 03:50	4.46	93%	75.9°
2038-06-15 Tue	53	—	unknown	01:30–03:40 (good, 2.17 h)	71.1° 03:45	4.45	98%	66.1°
2038-06-16 Wed	44	—	unknown	03:30–03:40 (good, 0.17 h)	71.1° 03:40	4.44	100%	57.3°
2038-06-17 Thu	39	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:40	4.43	99%	50.3°
2038-06-18 Fri	40	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:35	4.43	96%	45.9°
2038-06-19 Sat	68	—	unknown	23:10–23:25 (good, 0.25 h)	71.1° 03:30	4.42	90%	44.5°
2038-06-20 Sun	81	—	unknown	23:15–03:10 (good, 3.92 h)	71.1° 03:25	4.42	83%	46.3°
2038-06-21 Mon	94	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	74%	50.6°
2038-06-22 Tue	98	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.43	65%	56.6°
2038-06-23 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	56%	63.8°
2038-06-24 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	46%	71.6°
2038-06-25 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.45	37%	79.8°
2038-06-26 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.46	28%	88.2°
2038-06-27 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.47	20%	96.6°
2038-06-28 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	13%	105.0°
2038-06-29 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	7%	113.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-05-31&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.