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: 04-21 (100), 04-22 (100), 04-23 (100), 04-24 (100), 05-06 (100) — by astronomy; check the weather when the night is within four days.

2037-04-21astronomy score per night — click a bar for that night2037-05-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-04-21 Tue	100	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 05:55	6.93	37%	119.7°
2037-04-22 Wed	100	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 05:55	6.87	48%	117.5°
2037-04-23 Thu	100	—	unknown	00:05–04:45 (good, 4.67 h)	87.1° 05:50	6.81	59%	113.5°
2037-04-24 Fri	100	—	unknown	00:05–04:45 (good, 4.67 h)	87.1° 05:45	6.75	70%	108.1°
2037-04-25 Sat	88	—	unknown	00:10–04:40 (good, 4.5 h)	87.1° 05:40	6.69	80%	101.7°
2037-04-26 Sun	83	—	unknown	00:25–04:40 (good, 4.25 h)	87.1° 05:35	6.64	89%	94.6°
2037-04-27 Mon	72	—	unknown	01:15–04:40 (good, 3.42 h)	87.1° 05:35	6.58	95%	87.2°
2037-04-28 Tue	61	—	unknown	02:00–04:35 (good, 2.58 h)	87.1° 05:30	6.52	99%	80.0°
2037-04-29 Wed	55	—	unknown	02:35–04:35 (good, 2.0 h)	87.1° 05:25	6.46	100%	73.3°
2037-04-30 Thu	52	—	unknown	02:50–04:35 (good, 1.75 h)	87.1° 05:20	6.4	98%	67.7°
2037-05-01 Fri	52	—	unknown	02:25–04:30 (good, 2.08 h)	87.1° 05:20	6.34	94%	63.5°
2037-05-02 Sat	60	—	unknown	00:45–04:30 (good, 3.75 h)	87.1° 05:15	6.29	88%	60.8°
2037-05-03 Sun	84	—	unknown	23:15–04:25 (good, 5.17 h)	87.1° 05:10	6.23	80%	59.9°
2037-05-04 Mon	91	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:05	6.17	72%	60.7°
2037-05-05 Tue	97	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:00	6.11	62%	62.9°
2037-05-06 Wed	100	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 05:00	6.06	53%	66.3°
2037-05-07 Thu	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:55	6.0	43%	70.7°
2037-05-08 Fri	100	—	unknown	22:55–04:20 (good, 5.42 h)	87.1° 04:50	5.94	34%	75.8°
2037-05-09 Sat	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:45	5.89	25%	81.3°
2037-05-10 Sun	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:40	5.83	18%	87.2°
2037-05-11 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.78	11%	93.2°
2037-05-12 Tue	100	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.72	6%	99.2°
2037-05-13 Wed	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.67	2%	105.0°
2037-05-14 Thu	100	—	unknown	22:30–04:10 (good, 5.67 h)	87.1° 04:25	5.61	0%	110.2°
2037-05-15 Fri	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:25	5.56	1%	114.7°
2037-05-16 Sat	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.51	3%	118.0°
2037-05-17 Sun	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.46	8%	119.7°
2037-05-18 Mon	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.4	15%	119.7°
2037-05-19 Tue	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.35	24%	117.9°
2037-05-20 Wed	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.3	34%	114.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-04-21&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.