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: 05-23 (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.

2038-05-21astronomy score per night — click a bar for that night2038-06-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-05-21 Fri	89	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.27	87%	62.0°
2038-05-22 Sat	96	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.22	78%	63.9°
2038-05-23 Sun	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.17	69%	67.1°
2038-05-24 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.12	59%	71.3°
2038-05-25 Tue	100	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.08	49%	76.3°
2038-05-26 Wed	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.03	40%	81.6°
2038-05-27 Thu	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.99	31%	87.2°
2038-05-28 Fri	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.95	22%	92.8°
2038-05-29 Sat	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.91	15%	98.3°
2038-05-30 Sun	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.87	9%	103.5°
2038-05-31 Mon	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.83	4%	108.3°
2038-06-01 Tue	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.79	1%	112.4°
2038-06-02 Wed	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.76	0%	115.6°
2038-06-03 Thu	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.72	1%	117.6°
2038-06-04 Fri	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.69	4%	118.3°
2038-06-05 Sat	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:00	4.66	8%	117.4°
2038-06-06 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.63	15%	115.1°
2038-06-07 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.6	23%	111.4°
2038-06-08 Tue	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.58	33%	106.5°
2038-06-09 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.55	44%	100.7°
2038-06-10 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:40	4.53	55%	94.4°
2038-06-11 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:40	4.51	66%	87.7°
2038-06-12 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.49	77%	80.9°
2038-06-13 Sun	78	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.48	86%	74.6°
2038-06-14 Mon	67	—	unknown	23:20–03:40 (good, 4.33 h)	87.1° 02:25	4.46	93%	69.2°
2038-06-15 Tue	58	—	unknown	23:45–03:40 (good, 3.92 h)	87.1° 02:20	4.45	98%	65.0°
2038-06-16 Wed	53	—	unknown	02:20–03:40 (good, 1.33 h)	87.1° 02:20	4.44	100%	62.4°
2038-06-17 Thu	54	—	unknown	23:10–01:40 (good, 2.5 h)	87.1° 02:15	4.43	99%	61.8°
2038-06-18 Fri	63	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:10	4.43	96%	63.0°
2038-06-19 Sat	99	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:05	4.42	90%	65.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-05-21&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.