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: 09-10 (100), 09-11 (100), 09-12 (100), 09-13 (100), 09-14 (100) — by astronomy; check the weather when the night is within four days.

2028-09-10astronomy score per night — click a bar for that night2028-10-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-09-10 Sun	100	—	unknown	21:15–02:25 (good, 5.17 h)	87.1° 20:40	8.13	61%	107.9°
2028-09-11 Mon	100	—	unknown	21:15–02:25 (good, 5.17 h)	87.1° 20:35	8.19	51%	112.3°
2028-09-12 Tue	100	—	unknown	21:15–02:25 (good, 5.17 h)	87.1° 20:30	8.24	41%	115.7°
2028-09-13 Wed	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:25	8.29	30%	117.7°
2028-09-14 Thu	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:20	8.35	20%	118.1°
2028-09-15 Fri	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:20	8.4	12%	116.5°
2028-09-16 Sat	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.45	5%	113.1°
2028-09-17 Sun	100	—	unknown	21:05–02:10 (good, 5.08 h)	87.1° 20:10	8.5	1%	108.1°
2028-09-18 Mon	100	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.56	0%	101.9°
2028-09-19 Tue	100	—	unknown	21:00–02:00 (good, 5.0 h)	87.1° 20:00	8.61	2%	95.0°
2028-09-20 Wed	100	—	unknown	20:55–02:00 (good, 5.08 h)	87.1° 20:00	8.66	7%	87.9°
2028-09-21 Thu	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.71	14%	81.2°
2028-09-22 Fri	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:50	8.76	23%	75.0°
2028-09-23 Sat	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.81	33%	69.8°
2028-09-24 Sun	96	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:45	8.86	44%	65.8°
2028-09-25 Mon	89	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.91	54%	63.1°
2028-09-26 Tue	80	—	unknown	20:45–01:35 (good, 4.83 h)	87.1° 19:35	8.96	64%	61.8°
2028-09-27 Wed	62	—	unknown	20:45–01:00 (good, 4.25 h)	87.1° 19:30	9.01	73%	62.0°
2028-09-28 Thu	54	—	unknown	20:40–23:25 (good, 2.75 h)	87.1° 19:25	9.06	81%	63.5°
2028-09-29 Fri	49	—	unknown	20:40–22:30 (good, 1.83 h)	87.1° 19:25	9.11	88%	66.3°
2028-09-30 Sat	47	—	unknown	20:40–22:10 (good, 1.5 h)	87.1° 19:20	9.16	93%	70.0°
2028-10-01 Sun	48	—	unknown	20:35–22:10 (good, 1.58 h)	87.1° 19:15	9.2	97%	74.4°
2028-10-02 Mon	51	—	unknown	20:35–22:25 (good, 1.83 h)	87.1° 19:10	9.25	99%	79.5°
2028-10-03 Tue	56	—	unknown	20:35–22:50 (good, 2.25 h)	87.1° 19:05	9.3	100%	84.9°
2028-10-04 Wed	64	—	unknown	20:30–23:25 (good, 2.92 h)	87.1° 19:05	9.35	98%	90.6°
2028-10-05 Thu	72	—	unknown	20:30–00:05 (good, 3.58 h)	87.1° 19:00	9.39	95%	96.3°
2028-10-06 Fri	80	—	unknown	20:30–00:30 (good, 4.0 h)	87.1° 18:55	9.44	90%	101.8°
2028-10-07 Sat	100	—	unknown	20:25–00:30 (good, 4.08 h)	87.1° 18:50	9.49	84%	107.0°
2028-10-08 Sun	100	—	unknown	20:25–00:35 (good, 4.17 h)	87.1° 18:50	9.53	76%	111.5°
2028-10-09 Mon	100	—	unknown	20:25–00:35 (good, 4.17 h)	87.1° 18:45	9.58	66%	115.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-09-10&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.