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: 04-13 (100), 04-14 (100), 04-25 (100), 04-26 (100), 04-27 (100) — by astronomy; check the weather when the night is within four days.

2030-04-13astronomy score per night — click a bar for that night2030-05-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-04-13 Sat	100	—	unknown	00:50–05:05 (good, 4.25 h)	87.1° 06:30	7.41	77%	115.1°
2030-04-14 Sun	100	—	unknown	00:50–05:05 (good, 4.25 h)	87.1° 06:25	7.35	86%	110.0°
2030-04-15 Mon	87	—	unknown	00:50–05:00 (good, 4.17 h)	87.1° 06:20	7.29	93%	103.8°
2030-04-16 Tue	77	—	unknown	01:00–05:00 (good, 4.0 h)	87.1° 06:20	7.23	98%	96.6°
2030-04-17 Wed	68	—	unknown	01:35–05:00 (good, 3.42 h)	87.1° 06:15	7.18	100%	89.0°
2030-04-18 Thu	61	—	unknown	02:00–04:55 (good, 2.92 h)	87.1° 06:10	7.12	99%	81.3°
2030-04-19 Fri	57	—	unknown	02:05–04:55 (good, 2.83 h)	87.1° 06:05	7.06	95%	74.1°
2030-04-20 Sat	57	—	unknown	01:25–04:50 (good, 3.42 h)	87.1° 06:00	7.0	89%	67.8°
2030-04-21 Sun	70	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 06:00	6.94	80%	63.0°
2030-04-22 Mon	86	—	unknown	00:00–04:50 (good, 4.83 h)	87.1° 05:55	6.89	70%	60.0°
2030-04-23 Tue	92	—	unknown	23:55–04:45 (good, 4.83 h)	87.1° 05:50	6.83	59%	59.0°
2030-04-24 Wed	96	—	unknown	23:50–04:45 (good, 4.92 h)	87.1° 05:45	6.77	48%	60.0°
2030-04-25 Thu	100	—	unknown	23:50–04:45 (good, 4.92 h)	87.1° 05:40	6.71	38%	62.7°
2030-04-26 Fri	100	—	unknown	23:45–04:40 (good, 4.92 h)	87.1° 05:40	6.65	28%	66.7°
2030-04-27 Sat	100	—	unknown	23:40–04:40 (good, 5.0 h)	87.1° 05:35	6.59	20%	71.7°
2030-04-28 Sun	100	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:30	6.54	12%	77.4°
2030-04-29 Mon	100	—	unknown	23:30–04:35 (good, 5.08 h)	87.1° 05:25	6.48	7%	83.4°
2030-04-30 Tue	100	—	unknown	23:30–04:35 (good, 5.08 h)	87.1° 05:25	6.42	3%	89.6°
2030-05-01 Wed	100	—	unknown	23:25–04:30 (good, 5.08 h)	87.1° 05:20	6.36	0%	95.8°
2030-05-02 Thu	100	—	unknown	23:20–04:30 (good, 5.17 h)	87.1° 05:15	6.3	0%	101.7°
2030-05-03 Fri	100	—	unknown	23:15–04:30 (good, 5.25 h)	87.1° 05:10	6.25	2%	107.2°
2030-05-04 Sat	100	—	unknown	23:15–04:25 (good, 5.17 h)	87.1° 05:05	6.19	5%	112.1°
2030-05-05 Sun	100	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:05	6.13	10%	116.2°
2030-05-06 Mon	100	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 05:00	6.07	16%	119.1°
2030-05-07 Tue	100	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 04:55	6.02	24%	120.8°
2030-05-08 Wed	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:50	5.96	32%	121.0°
2030-05-09 Thu	100	—	unknown	23:00–04:15 (good, 5.25 h)	87.1° 04:45	5.9	42%	119.6°
2030-05-10 Fri	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:45	5.85	52%	116.6°
2030-05-11 Sat	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:40	5.79	63%	112.2°
2030-05-12 Sun	100	—	unknown	23:00–04:10 (good, 5.17 h)	87.1° 04:35	5.74	73%	106.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-13&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.