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: 04-26 (100), 04-27 (100), 04-28 (100), 04-29 (100), 04-30 (100) — by astronomy; check the weather when the night is within four days.

2030-04-26astronomy score per night — click a bar for that night2030-05-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2030-05-13 Mon	100	—	unknown	23:00–04:10 (good, 5.17 h)	87.1° 04:30	5.68	82%	99.9°
2030-05-14 Tue	84	—	unknown	23:10–04:10 (good, 5.0 h)	87.1° 04:30	5.63	90%	92.5°
2030-05-15 Wed	78	—	unknown	23:50–04:05 (good, 4.25 h)	87.1° 04:25	5.58	96%	84.8°
2030-05-16 Thu	70	—	unknown	00:30–04:05 (good, 3.58 h)	87.1° 04:20	5.52	100%	77.3°
2030-05-17 Fri	63	—	unknown	00:50–04:05 (good, 3.25 h)	87.1° 04:15	5.47	100%	70.4°
2030-05-18 Sat	60	—	unknown	00:35–04:00 (good, 3.42 h)	87.1° 04:10	5.42	97%	64.7°
2030-05-19 Sun	83	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.37	91%	60.8°
2030-05-20 Mon	89	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.32	83%	59.0°
2030-05-21 Tue	95	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.27	74%	59.3°
2030-05-22 Wed	99	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.22	64%	61.6°
2030-05-23 Thu	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.17	53%	65.4°
2030-05-24 Fri	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.13	43%	70.3°
2030-05-25 Sat	100	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.08	33%	75.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-26&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.