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: 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100), 09-30 (100) — by astronomy; check the weather when the night is within four days.

2045-09-13astronomy score per night — click a bar for that night2045-10-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-09-13 Wed	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:25	8.29	11%	87.0°
2045-09-14 Thu	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:25	8.34	20%	81.2°
2045-09-15 Fri	100	—	unknown	21:05–02:20 (good, 5.25 h)	87.1° 20:20	8.39	29%	76.0°
2045-09-16 Sat	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.45	39%	71.6°
2045-09-17 Sun	98	—	unknown	21:05–02:10 (good, 5.08 h)	87.1° 20:10	8.5	49%	68.2°
2045-09-18 Mon	91	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.55	58%	65.9°
2045-09-19 Tue	83	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.6	68%	64.7°
2045-09-20 Wed	68	—	unknown	20:55–01:30 (good, 4.58 h)	87.1° 20:00	8.65	76%	64.7°
2045-09-21 Thu	59	—	unknown	20:55–00:15 (good, 3.33 h)	87.1° 19:55	8.7	84%	65.9°
2045-09-22 Fri	54	—	unknown	20:55–23:10 (good, 2.25 h)	87.1° 19:50	8.75	90%	68.1°
2045-09-23 Sat	52	—	unknown	20:50–22:45 (good, 1.92 h)	87.1° 19:50	8.81	95%	71.3°
2045-09-24 Sun	53	—	unknown	20:50–22:45 (good, 1.92 h)	87.1° 19:45	8.86	98%	75.2°
2045-09-25 Mon	55	—	unknown	20:50–22:55 (good, 2.08 h)	87.1° 19:40	8.91	100%	79.8°
2045-09-26 Tue	61	—	unknown	20:45–23:20 (good, 2.58 h)	87.1° 19:35	8.96	100%	84.8°
2045-09-27 Wed	69	—	unknown	20:45–23:55 (good, 3.17 h)	87.1° 19:30	9.0	97%	90.2°
2045-09-28 Thu	77	—	unknown	20:45–00:35 (good, 3.83 h)	87.1° 19:30	9.05	93%	95.5°
2045-09-29 Fri	86	—	unknown	20:40–00:55 (good, 4.25 h)	87.1° 19:25	9.1	87%	100.8°
2045-09-30 Sat	100	—	unknown	20:40–01:00 (good, 4.33 h)	87.1° 19:20	9.15	79%	105.6°
2045-10-01 Sun	100	—	unknown	20:35–01:00 (good, 4.42 h)	87.1° 19:15	9.2	70%	109.8°
2045-10-02 Mon	100	—	unknown	20:35–01:05 (good, 4.5 h)	87.1° 19:10	9.25	59%	113.1°
2045-10-03 Tue	100	—	unknown	20:35–01:00 (good, 4.42 h)	87.1° 19:10	9.29	48%	115.0°
2045-10-04 Wed	100	—	unknown	20:30–01:05 (good, 4.58 h)	87.1° 19:05	9.34	37%	115.5°
2045-10-05 Thu	100	—	unknown	20:30–01:00 (good, 4.5 h)	87.1° 19:00	9.39	26%	114.3°
2045-10-06 Fri	100	—	unknown	20:30–00:55 (good, 4.42 h)	87.1° 18:55	9.43	17%	111.5°
2045-10-07 Sat	100	—	unknown	20:25–00:50 (good, 4.42 h)	87.1° 18:55	9.48	9%	107.2°
2045-10-08 Sun	100	—	unknown	20:25–00:50 (good, 4.42 h)	87.1° 18:50	9.53	3%	101.9°
2045-10-09 Mon	100	—	unknown	20:25–00:45 (good, 4.33 h)	87.1° 18:45	9.57	0%	95.9°
2045-10-10 Tue	100	—	unknown	20:20–00:40 (good, 4.33 h)	87.1° 18:40	9.62	0%	89.7°
2045-10-11 Wed	100	—	unknown	20:20–00:35 (good, 4.25 h)	87.1° 18:35	9.66	3%	83.6°
2045-10-12 Thu	100	—	unknown	20:20–00:30 (good, 4.17 h)	87.1° 18:35	9.71	8%	78.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-09-13&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.