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: 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100) — by astronomy; check the weather when the night is within four days.

2046-09-17astronomy score per night — click a bar for that night2046-10-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-09-17 Mon	77	—	unknown	21:05–00:40 (good, 3.58 h)	87.1° 20:10	8.49	94%	89.7°
2046-09-18 Tue	84	—	unknown	21:00–01:20 (good, 4.33 h)	87.1° 20:10	8.54	88%	95.1°
2046-09-19 Wed	88	—	unknown	21:00–01:40 (good, 4.67 h)	87.1° 20:05	8.59	82%	100.3°
2046-09-20 Thu	100	—	unknown	21:00–01:40 (good, 4.67 h)	87.1° 20:00	8.64	73%	105.3°
2046-09-21 Fri	100	—	unknown	20:55–01:45 (good, 4.83 h)	87.1° 19:55	8.69	64%	109.7°
2046-09-22 Sat	100	—	unknown	20:55–01:45 (good, 4.83 h)	87.1° 19:55	8.74	54%	113.3°
2046-09-23 Sun	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:50	8.79	44%	115.9°
2046-09-24 Mon	100	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:45	8.84	33%	117.1°
2046-09-25 Tue	100	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.89	23%	116.7°
2046-09-26 Wed	100	—	unknown	20:45–01:35 (good, 4.83 h)	87.1° 19:35	8.94	14%	114.5°
2046-09-27 Thu	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:35	8.99	7%	110.7°
2046-09-28 Fri	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:30	9.04	2%	105.4°
2046-09-29 Sat	100	—	unknown	20:40–01:25 (good, 4.75 h)	87.1° 19:25	9.09	0%	99.1°
2046-09-30 Sun	100	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:20	9.14	1%	92.3°
2046-10-01 Mon	100	—	unknown	20:40–01:15 (good, 4.58 h)	87.1° 19:15	9.19	5%	85.4°
2046-10-02 Tue	100	—	unknown	20:35–01:15 (good, 4.67 h)	87.1° 19:15	9.24	12%	78.9°
2046-10-03 Wed	100	—	unknown	20:35–01:10 (good, 4.58 h)	87.1° 19:10	9.28	20%	73.1°
2046-10-04 Thu	100	—	unknown	20:30–01:05 (good, 4.58 h)	87.1° 19:05	9.33	30%	68.5°
2046-10-05 Fri	93	—	unknown	20:30–01:00 (good, 4.5 h)	87.1° 19:00	9.38	40%	65.1°
2046-10-06 Sat	85	—	unknown	20:30–00:55 (good, 4.42 h)	87.1° 19:00	9.42	51%	63.2°
2046-10-07 Sun	70	—	unknown	20:25–00:35 (good, 4.17 h)	87.1° 18:55	9.47	61%	62.8°
2046-10-08 Mon	59	—	unknown	20:25–00:20 (good, 3.92 h)	87.1° 18:50	9.52	70%	63.7°
2046-10-09 Tue	52	—	unknown	20:25–22:55 (good, 2.5 h)	87.1° 18:45	9.56	78%	65.9°
2046-10-10 Wed	48	—	unknown	20:20–22:05 (good, 1.75 h)	87.1° 18:40	9.61	86%	69.1°
2046-10-11 Thu	46	—	unknown	20:20–21:50 (good, 1.5 h)	87.1° 18:40	9.65	92%	73.2°
2046-10-12 Fri	46	—	unknown	20:20–21:50 (good, 1.5 h)	87.1° 18:35	9.7	96%	77.9°
2046-10-13 Sat	49	—	unknown	20:20–22:05 (good, 1.75 h)	87.1° 18:30	9.74	99%	83.0°
2046-10-14 Sun	54	—	unknown	20:15–22:30 (good, 2.25 h)	87.1° 18:25	9.78	100%	88.3°
2046-10-15 Mon	61	—	unknown	20:15–23:00 (good, 2.75 h)	87.1° 18:20	9.83	99%	93.8°
2046-10-16 Tue	67	—	unknown	20:15–23:35 (good, 3.33 h)	87.1° 18:20	9.87	96%	99.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-09-17&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.