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: 05-09 (100), 05-10 (100), 05-20 (100), 05-21 (100), 05-22 (100) — by astronomy; check the weather when the night is within four days.

2041-05-09astronomy score per night — click a bar for that night2041-06-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-05-09 Thu	100	—	unknown	23:10–04:15 (good, 5.08 h)	87.1° 04:45	5.89	66%	101.9°
2041-05-10 Fri	100	—	unknown	23:15–04:15 (good, 5.0 h)	87.1° 04:40	5.83	75%	97.4°
2041-05-11 Sat	85	—	unknown	23:20–04:15 (good, 4.92 h)	87.1° 04:40	5.77	83%	92.6°
2041-05-12 Sun	80	—	unknown	23:55–04:10 (good, 4.25 h)	87.1° 04:35	5.72	90%	87.6°
2041-05-13 Mon	76	—	unknown	00:25–04:10 (good, 3.75 h)	87.1° 04:30	5.67	95%	82.6°
2041-05-14 Tue	71	—	unknown	00:50–04:10 (good, 3.33 h)	87.1° 04:25	5.61	99%	77.8°
2041-05-15 Wed	65	—	unknown	00:55–04:05 (good, 3.17 h)	87.1° 04:25	5.56	100%	73.5°
2041-05-16 Thu	63	—	unknown	00:40–04:05 (good, 3.42 h)	87.1° 04:20	5.51	99%	69.9°
2041-05-17 Fri	74	—	unknown	23:15–04:05 (good, 4.83 h)	87.1° 04:15	5.45	96%	67.4°
2041-05-18 Sat	87	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.4	90%	66.2°
2041-05-19 Sun	95	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.35	82%	66.5°
2041-05-20 Mon	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.3	72%	68.4°
2041-05-21 Tue	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.25	62%	71.5°
2041-05-22 Wed	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.2	50%	75.8°
2041-05-23 Thu	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.16	39%	80.8°
2041-05-24 Fri	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:45	5.11	28%	86.3°
2041-05-25 Sat	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:45	5.07	18%	91.9°
2041-05-26 Sun	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.02	10%	97.4°
2041-05-27 Mon	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.98	5%	102.5°
2041-05-28 Tue	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.94	1%	106.9°
2041-05-29 Wed	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.9	0%	110.3°
2041-05-30 Thu	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.86	1%	112.7°
2041-05-31 Fri	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.82	4%	113.8°
2041-06-01 Sat	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.78	9%	113.7°
2041-06-02 Sun	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.75	16%	112.4°
2041-06-03 Mon	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.71	23%	110.2°
2041-06-04 Tue	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:05	4.68	32%	107.1°
2041-06-05 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 03:00	4.65	41%	103.3°
2041-06-06 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.62	50%	99.0°
2041-06-07 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.6	60%	94.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-05-09&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.