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: 09-26 (100), 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100) — by astronomy; check the weather when the night is within four days.

2040-09-26astronomy score per night — click a bar for that night2040-10-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-09-26 Wed	100	—	unknown	20:45–01:25 (good, 4.67 h)	87.1° 19:35	8.97	62%	113.4°
2040-09-27 Thu	100	—	unknown	20:45–01:25 (good, 4.67 h)	87.1° 19:30	9.01	53%	114.5°
2040-09-28 Fri	100	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:25	9.06	43%	114.4°
2040-09-29 Sat	100	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:25	9.11	34%	113.3°
2040-09-30 Sun	100	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:20	9.16	25%	111.1°
2040-10-01 Mon	100	—	unknown	20:35–01:15 (good, 4.67 h)	87.1° 19:15	9.21	18%	108.0°
2040-10-02 Tue	100	—	unknown	20:35–01:10 (good, 4.58 h)	87.1° 19:10	9.26	11%	104.2°
2040-10-03 Wed	100	—	unknown	20:35–01:05 (good, 4.5 h)	87.1° 19:05	9.3	6%	99.6°
2040-10-04 Thu	100	—	unknown	20:30–01:05 (good, 4.58 h)	87.1° 19:05	9.35	2%	94.7°
2040-10-05 Fri	100	—	unknown	20:30–01:00 (good, 4.5 h)	87.1° 19:00	9.4	0%	89.4°
2040-10-06 Sat	100	—	unknown	20:30–00:55 (good, 4.42 h)	87.1° 18:55	9.44	1%	84.1°
2040-10-07 Sun	100	—	unknown	20:25–00:50 (good, 4.42 h)	87.1° 18:50	9.49	3%	78.9°
2040-10-08 Mon	100	—	unknown	20:25–00:45 (good, 4.33 h)	87.1° 18:50	9.54	8%	74.2°
2040-10-09 Tue	100	—	unknown	20:25–00:45 (good, 4.33 h)	87.1° 18:45	9.58	15%	70.2°
2040-10-10 Wed	100	—	unknown	20:20–00:40 (good, 4.33 h)	87.1° 18:40	9.63	24%	67.3°
2040-10-11 Thu	94	—	unknown	20:20–00:35 (good, 4.25 h)	87.1° 18:35	9.67	34%	65.7°
2040-10-12 Fri	86	—	unknown	20:20–00:30 (good, 4.17 h)	87.1° 18:30	9.72	45%	65.7°
2040-10-13 Sat	72	—	unknown	20:15–00:25 (good, 4.17 h)	87.1° 18:30	9.76	56%	67.2°
2040-10-14 Sun	62	—	unknown	20:15–00:00 (good, 3.75 h)	87.1° 18:25	9.8	68%	70.1°
2040-10-15 Mon	56	—	unknown	20:15–23:30 (good, 3.25 h)	87.1° 18:20	9.85	78%	74.2°
2040-10-16 Tue	54	—	unknown	20:10–22:50 (good, 2.67 h)	87.1° 18:15	9.89	87%	79.3°
2040-10-17 Wed	54	—	unknown	20:10–22:35 (good, 2.42 h)	87.1° 18:10	9.93	93%	84.8°
2040-10-18 Thu	56	—	unknown	20:10–22:45 (good, 2.58 h)	87.1° 18:10	9.98	98%	90.6°
2040-10-19 Fri	60	—	unknown	20:10–23:00 (good, 2.83 h)	87.1° 18:05	10.02	100%	96.3°
2040-10-20 Sat	66	—	unknown	20:05–23:30 (good, 3.42 h)	87.1° 18:00	10.06	99%	101.6°
2040-10-21 Sun	71	—	unknown	20:05–23:30 (good, 3.42 h)	87.1° 17:55	10.1	97%	106.2°
2040-10-22 Mon	77	—	unknown	20:05–23:35 (good, 3.5 h)	87.1° 17:55	10.14	92%	109.9°
2040-10-23 Tue	89	—	unknown	20:05–23:35 (good, 3.5 h)	87.1° 17:50	10.18	86%	112.5°
2040-10-24 Wed	92	—	unknown	20:00–23:35 (good, 3.58 h)	87.1° 17:45	10.22	78%	114.1°
2040-10-25 Thu	92	—	unknown	20:00–23:30 (good, 3.5 h)	87.1° 17:40	10.26	69%	114.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-09-26&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.