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 Vega: 05-27 (100), 05-28 (100), 05-29 (100), 06-07 (100), 06-08 (100) — by astronomy; check the weather when the night is within four days.

2042-05-27astronomy score per night — click a bar for that night2042-06-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-05-27 Tue	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.99	61%	99.1°
2042-05-28 Wed	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.95	70%	94.6°
2042-05-29 Thu	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.91	78%	90.0°
2042-05-30 Fri	82	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.87	86%	85.3°
2042-05-31 Sat	79	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:20	4.83	92%	80.8°
2042-06-01 Sun	73	—	unknown	23:20–03:45 (good, 4.42 h)	87.1° 03:15	4.79	96%	76.5°
2042-06-02 Mon	67	—	unknown	23:25–03:45 (good, 4.33 h)	87.1° 03:15	4.76	99%	72.8°
2042-06-03 Tue	63	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.72	100%	69.8°
2042-06-04 Wed	63	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.69	99%	67.7°
2042-06-05 Thu	89	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:00	4.66	95%	66.8°
2042-06-06 Fri	96	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.63	90%	67.1°
2042-06-07 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.6	82%	68.8°
2042-06-08 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.58	73%	71.7°
2042-06-09 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.55	62%	75.7°
2042-06-10 Tue	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:40	4.53	51%	80.5°
2042-06-11 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:40	4.51	40%	85.9°
2042-06-12 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.49	29%	91.5°
2042-06-13 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.48	19%	97.1°
2042-06-14 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.46	11%	102.3°
2042-06-15 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.45	5%	106.8°
2042-06-16 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.44	1%	110.2°
2042-06-17 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:15	4.43	0%	112.5°
2042-06-18 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:10	4.43	2%	113.3°
2042-06-19 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:05	4.42	6%	112.8°
2042-06-20 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 02:00	4.42	11%	111.0°
2042-06-21 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 02:00	4.42	18%	108.3°
2042-06-22 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:55	4.42	26%	104.8°
2042-06-23 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:50	4.43	36%	100.7°
2042-06-24 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:45	4.44	45%	96.3°
2042-06-25 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:45	4.44	54%	91.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-05-27&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.