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: 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100), 09-25 (100) — by astronomy; check the weather when the night is within four days.

2030-09-21astronomy score per night — click a bar for that night2030-10-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-09-21 Sat	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.69	30%	121.4°
2030-09-22 Sun	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:55	8.74	22%	120.6°
2030-09-23 Mon	100	—	unknown	20:50–01:50 (good, 5.0 h)	87.1° 19:50	8.79	14%	118.2°
2030-09-24 Tue	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.84	8%	114.2°
2030-09-25 Wed	100	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.89	3%	109.0°
2030-09-26 Thu	100	—	unknown	20:45–01:35 (good, 4.83 h)	87.1° 19:35	8.94	0%	102.6°
2030-09-27 Fri	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:35	8.99	0%	95.5°
2030-09-28 Sat	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:30	9.04	3%	88.1°
2030-09-29 Sun	100	—	unknown	20:40–01:25 (good, 4.75 h)	87.1° 19:25	9.08	8%	80.7°
2030-09-30 Mon	100	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:20	9.13	16%	73.6°
2030-10-01 Tue	100	—	unknown	20:40–01:15 (good, 4.58 h)	87.1° 19:15	9.18	25%	67.5°
2030-10-02 Wed	95	—	unknown	20:35–01:15 (good, 4.67 h)	87.1° 19:15	9.23	36%	62.7°
2030-10-03 Thu	87	—	unknown	20:35–01:10 (good, 4.58 h)	87.1° 19:10	9.28	47%	59.6°
2030-10-04 Fri	70	—	unknown	20:35–01:05 (good, 4.5 h)	87.1° 19:05	9.32	58%	58.5°
2030-10-05 Sat	58	—	unknown	20:30–00:30 (good, 4.0 h)	87.1° 19:00	9.37	69%	59.4°
2030-10-06 Sun	50	—	unknown	20:30–22:35 (good, 2.08 h)	87.1° 19:00	9.42	79%	62.2°
2030-10-07 Mon	45	—	unknown	20:30–21:50 (good, 1.33 h)	87.1° 18:55	9.46	87%	66.5°
2030-10-08 Tue	45	—	unknown	20:25–21:45 (good, 1.33 h)	87.1° 18:50	9.51	93%	71.9°
2030-10-09 Wed	47	—	unknown	20:25–21:55 (good, 1.5 h)	87.1° 18:45	9.56	97%	78.0°
2030-10-10 Thu	52	—	unknown	20:25–22:25 (good, 2.0 h)	87.1° 18:40	9.6	100%	84.4°
2030-10-11 Fri	60	—	unknown	20:20–23:00 (good, 2.67 h)	87.1° 18:40	9.65	100%	91.0°
2030-10-12 Sat	68	—	unknown	20:20–23:40 (good, 3.33 h)	87.1° 18:35	9.69	98%	97.4°
2030-10-13 Sun	75	—	unknown	20:20–00:05 (good, 3.75 h)	87.1° 18:30	9.74	94%	103.5°
2030-10-14 Mon	94	—	unknown	20:15–00:05 (good, 3.83 h)	87.1° 18:25	9.78	89%	109.0°
2030-10-15 Tue	99	—	unknown	20:15–00:10 (good, 3.92 h)	87.1° 18:20	9.82	82%	113.8°
2030-10-16 Wed	100	—	unknown	20:15–00:10 (good, 3.92 h)	87.1° 18:20	9.87	75%	117.6°
2030-10-17 Thu	100	—	unknown	20:10–00:05 (good, 3.92 h)	87.1° 18:15	9.91	66%	120.3°
2030-10-18 Fri	100	—	unknown	20:10–00:05 (good, 3.92 h)	87.1° 18:10	9.95	57%	121.6°
2030-10-19 Sat	100	—	unknown	20:10–00:05 (good, 3.92 h)	87.1° 18:05	9.99	47%	121.3°
2030-10-20 Sun	100	—	unknown	20:05–00:00 (good, 3.92 h)	87.1° 18:05	10.03	37%	119.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-09-21&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.