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: 04-09 (100), 04-10 (100), 04-11 (100), 04-12 (100), 04-13 (100) — by astronomy; check the weather when the night is within four days.

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

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-04-05 Sun	71	—	unknown	01:05–05:20 (good, 4.25 h)	87.1° 07:00	7.84	65%	60.0°
2037-04-06 Mon	85	—	unknown	01:00–05:20 (good, 4.33 h)	87.1° 06:55	7.79	55%	59.8°
2037-04-07 Tue	93	—	unknown	01:00–05:15 (good, 4.25 h)	87.1° 06:50	7.73	46%	61.0°
2037-04-08 Wed	99	—	unknown	00:55–05:15 (good, 4.33 h)	87.1° 06:50	7.67	36%	63.7°
2037-04-09 Thu	100	—	unknown	00:50–05:15 (good, 4.42 h)	87.1° 06:45	7.62	27%	67.4°
2037-04-10 Fri	100	—	unknown	00:45–05:10 (good, 4.42 h)	87.1° 06:40	7.56	19%	72.0°
2037-04-11 Sat	100	—	unknown	00:40–05:10 (good, 4.5 h)	87.1° 06:35	7.5	12%	77.2°
2037-04-12 Sun	100	—	unknown	00:40–05:05 (good, 4.42 h)	87.1° 06:35	7.45	7%	82.9°
2037-04-13 Mon	100	—	unknown	00:35–05:05 (good, 4.5 h)	87.1° 06:30	7.39	3%	88.9°
2037-04-14 Tue	100	—	unknown	00:30–05:05 (good, 4.58 h)	87.1° 06:25	7.33	1%	95.0°
2037-04-15 Wed	100	—	unknown	00:25–05:00 (good, 4.58 h)	87.1° 06:20	7.27	0%	100.9°
2037-04-16 Thu	100	—	unknown	00:25–05:00 (good, 4.58 h)	87.1° 06:15	7.22	2%	106.6°
2037-04-17 Fri	100	—	unknown	00:20–04:55 (good, 4.58 h)	87.1° 06:15	7.16	5%	111.6°
2037-04-18 Sat	100	—	unknown	00:15–04:55 (good, 4.67 h)	87.1° 06:10	7.1	11%	115.8°
2037-04-19 Sun	100	—	unknown	00:10–04:55 (good, 4.75 h)	87.1° 06:05	7.04	18%	118.7°
2037-04-20 Mon	100	—	unknown	00:10–04:50 (good, 4.67 h)	87.1° 06:00	6.98	27%	120.1°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-04-05&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.