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: 10-18 (100), 10-19 (100), 10-20 (100), 10-21 (100), 10-22 (100) — by astronomy; check the weather when the night is within four days.

2041-10-18astronomy score per night — click a bar for that night2041-11-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-10-18 Fri	100	—	unknown	20:10–00:10 (good, 4.0 h)	87.1° 18:10	9.97	31%	108.4°
2041-10-19 Sat	100	—	unknown	20:10–00:05 (good, 3.92 h)	87.1° 18:05	10.01	22%	105.0°
2041-10-20 Sun	100	—	unknown	20:05–00:00 (good, 3.92 h)	87.1° 18:00	10.05	15%	101.1°
2041-10-21 Mon	100	—	unknown	20:05–23:55 (good, 3.83 h)	87.1° 18:00	10.09	9%	96.7°
2041-10-22 Tue	100	—	unknown	20:05–23:55 (good, 3.83 h)	87.1° 17:55	10.13	4%	92.0°
2041-10-23 Wed	98	—	unknown	20:05–23:50 (good, 3.75 h)	87.1° 17:50	10.17	1%	87.2°
2041-10-24 Thu	98	—	unknown	20:00–23:45 (good, 3.75 h)	87.1° 17:45	10.21	0%	82.5°
2041-10-25 Fri	97	—	unknown	20:00–23:40 (good, 3.67 h)	87.1° 17:40	10.25	1%	78.0°
2041-10-26 Sat	95	—	unknown	20:00–23:35 (good, 3.58 h)	87.1° 17:40	10.29	3%	73.9°
2041-10-27 Sun	94	—	unknown	19:00–22:35 (good, 3.58 h)	87.1° 16:35	10.33	8%	70.5°
2041-10-28 Mon	92	—	unknown	18:55–22:30 (good, 3.58 h)	87.1° 16:30	10.37	15%	68.1°
2041-10-29 Tue	83	—	unknown	18:55–22:25 (good, 3.5 h)	87.1° 16:25	10.4	23%	66.8°
2041-10-30 Wed	76	—	unknown	18:55–22:20 (good, 3.42 h)	87.1° 16:20	10.44	33%	66.8°
2041-10-31 Thu	66	—	unknown	18:55–22:05 (good, 3.17 h)	87.1° 16:20	10.48	44%	68.1°
2041-11-01 Fri	58	—	unknown	18:50–21:55 (good, 3.08 h)	87.1° 16:15	10.51	55%	70.8°
2041-11-02 Sat	51	—	unknown	18:50–21:45 (good, 2.92 h)	87.1° 16:10	10.55	66%	74.7°
2041-11-03 Sun	47	—	unknown	18:50–21:15 (good, 2.42 h)	87.1° 16:05	10.59	76%	79.5°
2041-11-04 Mon	44	—	unknown	18:50–20:50 (good, 2.0 h)	87.1° 16:05	10.62	86%	85.0°
2041-11-05 Tue	44	—	unknown	18:50–20:45 (good, 1.92 h)	87.1° 16:00	10.66	93%	90.8°
2041-11-06 Wed	46	—	unknown	18:45–20:55 (good, 2.17 h)	87.1° 15:55	10.69	98%	96.5°
2041-11-07 Thu	49	—	unknown	18:45–21:20 (good, 2.58 h)	87.1° 15:50	10.72	100%	101.9°
2041-11-08 Fri	54	—	unknown	18:45–21:20 (good, 2.58 h)	87.1° 15:45	10.76	99%	106.4°
2041-11-09 Sat	57	—	unknown	18:45–21:25 (good, 2.67 h)	87.1° 15:45	10.79	96%	110.0°
2041-11-10 Sun	60	—	unknown	18:45–21:25 (good, 2.67 h)	87.1° 15:40	10.82	91%	112.3°
2041-11-11 Mon	69	—	unknown	18:40–21:25 (good, 2.75 h)	87.1° 15:35	10.85	84%	113.4°
2041-11-12 Tue	70	—	unknown	18:40–21:20 (good, 2.67 h)	87.1° 15:30	10.88	76%	113.1°
2041-11-13 Wed	70	—	unknown	18:40–21:25 (good, 2.75 h)	87.1° 15:25	10.91	67%	111.7°
2041-11-14 Thu	69	—	unknown	18:40–21:25 (good, 2.75 h)	87.1° 15:25	10.94	57%	109.4°
2041-11-15 Fri	67	—	unknown	18:40–21:20 (good, 2.67 h)	87.1° 15:20	10.97	48%	106.2°
2041-11-16 Sat	66	—	unknown	18:40–21:15 (good, 2.58 h)	87.1° 15:15	11.0	38%	102.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-10-18&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.