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: 05-02 (100), 05-03 (100), 05-04 (100), 05-05 (100), 05-06 (100) — by astronomy; check the weather when the night is within four days.

2040-04-24astronomy score per night — click a bar for that night2040-05-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-04-24 Tue	74	—	unknown	01:10–04:45 (good, 3.58 h)	87.1° 05:45	6.74	94%	89.9°
2040-04-25 Wed	66	—	unknown	01:45–04:40 (good, 2.92 h)	87.1° 05:40	6.68	98%	84.2°
2040-04-26 Thu	60	—	unknown	02:10–04:40 (good, 2.5 h)	87.1° 05:35	6.62	100%	78.6°
2040-04-27 Fri	57	—	unknown	02:15–04:40 (good, 2.42 h)	87.1° 05:35	6.56	99%	73.5°
2040-04-28 Sat	56	—	unknown	01:55–04:35 (good, 2.67 h)	87.1° 05:30	6.5	96%	69.3°
2040-04-29 Sun	63	—	unknown	00:25–04:35 (good, 4.17 h)	87.1° 05:25	6.44	90%	66.4°
2040-04-30 Mon	85	—	unknown	23:25–04:30 (good, 5.08 h)	87.1° 05:20	6.39	81%	65.0°
2040-05-01 Tue	93	—	unknown	23:25–04:30 (good, 5.08 h)	87.1° 05:15	6.33	71%	65.3°
2040-05-02 Wed	100	—	unknown	23:20–04:30 (good, 5.17 h)	87.1° 05:15	6.27	60%	67.3°
2040-05-03 Thu	100	—	unknown	23:15–04:25 (good, 5.17 h)	87.1° 05:10	6.21	49%	70.6°
2040-05-04 Fri	100	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:05	6.16	38%	75.0°
2040-05-05 Sat	100	—	unknown	23:05–04:25 (good, 5.33 h)	87.1° 05:00	6.1	27%	80.1°
2040-05-06 Sun	100	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 04:55	6.04	18%	85.6°
2040-05-07 Mon	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:55	5.98	11%	91.2°
2040-05-08 Tue	100	—	unknown	22:55–04:20 (good, 5.42 h)	87.1° 04:50	5.93	5%	96.6°
2040-05-09 Wed	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:45	5.87	2%	101.7°
2040-05-10 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.82	0%	106.2°
2040-05-11 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.76	1%	110.0°
2040-05-12 Sat	100	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.71	3%	112.8°
2040-05-13 Sun	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.65	7%	114.5°
2040-05-14 Mon	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:25	5.6	13%	115.0°
2040-05-15 Tue	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.55	20%	114.5°
2040-05-16 Wed	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.49	28%	112.8°
2040-05-17 Thu	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.44	37%	110.1°
2040-05-18 Fri	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.39	46%	106.6°
2040-05-19 Sat	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.34	56%	102.3°
2040-05-20 Sun	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.29	66%	97.4°
2040-05-21 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 04:00	5.24	75%	92.1°
2040-05-22 Tue	82	—	unknown	23:05–03:55 (good, 4.83 h)	87.1° 03:55	5.19	84%	86.5°
2040-05-23 Wed	77	—	unknown	23:45–03:55 (good, 4.17 h)	87.1° 03:50	5.15	91%	80.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-04-24&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.