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: 04-27 (100), 05-08 (100), 05-09 (100), 05-10 (100), 05-11 (100) — by astronomy; check the weather when the night is within four days.

2045-04-27astronomy score per night — click a bar for that night2045-05-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-27 Thu	100	—	unknown	00:05–04:40 (good, 4.58 h)	87.1° 05:35	6.57	87%	101.2°
2045-04-28 Fri	83	—	unknown	00:10–04:35 (good, 4.42 h)	87.1° 05:30	6.51	94%	95.6°
2045-04-29 Sat	78	—	unknown	00:40–04:35 (good, 3.92 h)	87.1° 05:25	6.46	98%	89.8°
2045-04-30 Sun	71	—	unknown	00:55–04:30 (good, 3.58 h)	87.1° 05:20	6.4	100%	84.1°
2045-05-01 Mon	67	—	unknown	01:00–04:30 (good, 3.5 h)	87.1° 05:20	6.34	99%	78.8°
2045-05-02 Tue	65	—	unknown	00:40–04:30 (good, 3.83 h)	87.1° 05:15	6.28	97%	74.1°
2045-05-03 Wed	68	—	unknown	23:45–04:25 (good, 4.67 h)	87.1° 05:10	6.22	92%	70.2°
2045-05-04 Thu	84	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:05	6.17	86%	67.3°
2045-05-05 Fri	90	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:00	6.11	78%	65.5°
2045-05-06 Sat	95	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 05:00	6.05	70%	64.9°
2045-05-07 Sun	99	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:55	6.0	61%	65.5°
2045-05-08 Mon	100	—	unknown	22:55–04:20 (good, 5.42 h)	87.1° 04:50	5.94	52%	67.1°
2045-05-09 Tue	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:45	5.88	42%	69.8°
2045-05-10 Wed	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:40	5.83	33%	73.3°
2045-05-11 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.77	24%	77.6°
2045-05-12 Fri	100	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.72	16%	82.5°
2045-05-13 Sat	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.66	10%	87.8°
2045-05-14 Sun	100	—	unknown	22:30–04:10 (good, 5.67 h)	87.1° 04:25	5.61	4%	93.4°
2045-05-15 Mon	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:25	5.56	1%	99.0°
2045-05-16 Tue	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.5	0%	104.3°
2045-05-17 Wed	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.45	2%	108.9°
2045-05-18 Thu	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.4	6%	112.4°
2045-05-19 Fri	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.35	13%	114.6°
2045-05-20 Sat	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.3	22%	115.2°
2045-05-21 Sun	100	—	unknown	22:45–04:00 (good, 5.25 h)	87.1° 04:00	5.25	32%	114.0°
2045-05-22 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.2	43%	111.4°
2045-05-23 Tue	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.16	55%	107.5°
2045-05-24 Wed	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:45	5.11	66%	102.6°
2045-05-25 Thu	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:45	5.06	76%	97.2°
2045-05-26 Fri	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.02	84%	91.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-27&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.