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: 03-27 (100), 03-28 (100), 03-29 (100), 03-30 (100), 03-31 (100) — by astronomy; check the weather when the night is within four days.

2041-03-17astronomy score per night — click a bar for that night2041-04-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-03-17 Sun	52	—	unknown	02:30–04:55 (good, 2.42 h)	87.1° 07:15	8.86	100%	94.4°
2041-03-18 Mon	50	—	unknown	02:50–04:55 (good, 2.08 h)	87.1° 07:10	8.81	99%	89.5°
2041-03-19 Tue	48	—	unknown	02:55–04:55 (good, 2.0 h)	87.1° 07:05	8.75	96%	84.5°
2041-03-20 Wed	47	—	unknown	02:50–04:50 (good, 2.0 h)	87.1° 07:05	8.7	91%	79.6°
2041-03-21 Thu	49	—	unknown	02:20–04:50 (good, 2.5 h)	87.1° 07:00	8.65	84%	75.2°
2041-03-22 Fri	54	—	unknown	01:30–04:50 (good, 3.33 h)	87.1° 06:55	8.6	76%	71.3°
2041-03-23 Sat	61	—	unknown	01:20–04:45 (good, 3.42 h)	87.1° 06:50	8.55	66%	68.3°
2041-03-24 Sun	74	—	unknown	00:55–04:45 (good, 3.83 h)	87.1° 06:45	8.49	56%	66.5°
2041-03-25 Mon	87	—	unknown	00:50–04:40 (good, 3.83 h)	87.1° 06:45	8.44	44%	66.1°
2041-03-26 Tue	98	—	unknown	00:45–04:40 (good, 3.92 h)	87.1° 06:40	8.39	33%	67.1°
2041-03-27 Wed	100	—	unknown	00:40–04:40 (good, 4.0 h)	87.1° 06:35	8.33	23%	69.7°
2041-03-28 Thu	100	—	unknown	00:35–04:35 (good, 4.0 h)	87.1° 06:30	8.28	14%	73.5°
2041-03-29 Fri	100	—	unknown	00:35–04:35 (good, 4.0 h)	87.1° 06:30	8.23	7%	78.5°
2041-03-30 Sat	100	—	unknown	00:30–05:35 (good, 4.08 h)	87.1° 07:25	8.17	2%	84.1°
2041-03-31 Sun	100	—	unknown	01:25–05:30 (good, 4.08 h)	87.1° 07:20	8.12	0%	90.1°
2041-04-01 Mon	100	—	unknown	01:20–05:30 (good, 4.17 h)	87.1° 07:15	8.06	1%	95.9°
2041-04-02 Tue	100	—	unknown	01:20–05:25 (good, 4.08 h)	87.1° 07:10	8.01	5%	101.3°
2041-04-03 Wed	100	—	unknown	01:15–05:25 (good, 4.17 h)	87.1° 07:10	7.95	10%	105.9°
2041-04-04 Thu	100	—	unknown	01:10–05:25 (good, 4.25 h)	87.1° 07:05	7.9	18%	109.6°
2041-04-05 Fri	100	—	unknown	01:10–05:20 (good, 4.17 h)	87.1° 07:00	7.84	26%	112.2°
2041-04-06 Sat	100	—	unknown	01:05–05:20 (good, 4.25 h)	87.1° 06:55	7.78	36%	113.6°
2041-04-07 Sun	100	—	unknown	01:05–05:15 (good, 4.17 h)	87.1° 06:50	7.73	46%	113.8°
2041-04-08 Mon	100	—	unknown	01:05–05:15 (good, 4.17 h)	87.1° 06:50	7.67	55%	112.9°
2041-04-09 Tue	100	—	unknown	01:00–05:15 (good, 4.25 h)	87.1° 06:45	7.62	64%	111.0°
2041-04-10 Wed	100	—	unknown	01:00–05:10 (good, 4.17 h)	87.1° 06:40	7.56	73%	108.2°
2041-04-11 Thu	89	—	unknown	01:05–05:10 (good, 4.08 h)	87.1° 06:35	7.5	81%	104.6°
2041-04-12 Fri	82	—	unknown	01:05–05:05 (good, 4.0 h)	87.1° 06:35	7.44	88%	100.5°
2041-04-13 Sat	74	—	unknown	01:20–05:05 (good, 3.75 h)	87.1° 06:30	7.39	94%	95.9°
2041-04-14 Sun	68	—	unknown	01:50–05:05 (good, 3.25 h)	87.1° 06:25	7.33	98%	91.0°
2041-04-15 Mon	61	—	unknown	02:15–05:00 (good, 2.75 h)	87.1° 06:20	7.27	100%	85.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-03-17&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.