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: 02-17 (63), 02-16 (62), 02-15 (60), 02-13 (59), 02-14 (58) — by astronomy; check the weather when the night is within four days.

2040-01-19astronomy score per night — click a bar for that night2040-02-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-01-19 Thu	28	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:00	11.14	38%	94.1°
2040-01-20 Fri	30	—	unknown	05:05–06:10 (good, 1.08 h)	87.1° 11:00	11.12	48%	99.4°
2040-01-21 Sat	30	—	unknown	05:00–06:05 (good, 1.08 h)	87.1° 10:55	11.09	58%	104.2°
2040-01-22 Sun	31	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:50	11.07	68%	108.4°
2040-01-23 Mon	33	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:45	11.04	76%	111.7°
2040-01-24 Tue	33	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:40	11.01	84%	114.2°
2040-01-25 Wed	33	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:40	10.98	90%	115.5°
2040-01-26 Thu	29	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:35	10.96	95%	115.7°
2040-01-27 Fri	29	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:30	10.93	98%	114.7°
2040-01-28 Sat	28	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:25	10.9	100%	112.6°
2040-01-29 Sun	27	—	unknown	04:50–06:00 (good, 1.17 h)	87.1° 10:25	10.87	100%	109.5°
2040-01-30 Mon	26	—	unknown	04:50–06:00 (good, 1.17 h)	87.1° 10:20	10.83	97%	105.5°
2040-01-31 Tue	25	—	unknown	04:50–06:00 (good, 1.17 h)	87.1° 10:15	10.8	93%	100.8°
2040-02-01 Wed	25	—	unknown	04:55–06:00 (good, 1.08 h)	87.1° 10:10	10.77	88%	95.5°
2040-02-02 Thu	25	—	unknown	04:50–06:00 (good, 1.17 h)	87.1° 10:05	10.74	80%	90.0°
2040-02-03 Fri	27	—	unknown	04:40–06:00 (good, 1.33 h)	87.1° 10:05	10.7	71%	84.4°
2040-02-04 Sat	28	—	unknown	04:30–05:55 (good, 1.42 h)	87.1° 10:00	10.67	61%	78.9°
2040-02-05 Sun	32	—	unknown	04:20–05:55 (good, 1.58 h)	87.1° 09:55	10.64	50%	73.8°
2040-02-06 Mon	37	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:50	10.6	39%	69.5°
2040-02-07 Tue	42	—	unknown	04:00–05:55 (good, 1.92 h)	87.1° 09:45	10.56	28%	66.3°
2040-02-08 Wed	48	—	unknown	03:50–05:55 (good, 2.08 h)	87.1° 09:45	10.53	18%	64.6°
2040-02-09 Thu	52	—	unknown	03:45–05:50 (good, 2.08 h)	87.1° 09:40	10.49	10%	64.6°
2040-02-10 Fri	54	—	unknown	03:40–05:50 (good, 2.17 h)	87.1° 09:35	10.45	4%	66.3°
2040-02-11 Sat	55	—	unknown	03:35–05:50 (good, 2.25 h)	87.1° 09:30	10.42	1%	69.8°
2040-02-12 Sun	57	—	unknown	03:35–05:50 (good, 2.25 h)	87.1° 09:25	10.38	0%	74.4°
2040-02-13 Mon	59	—	unknown	03:30–05:50 (good, 2.33 h)	87.1° 09:25	10.34	3%	79.9°
2040-02-14 Tue	58	—	unknown	03:25–05:45 (good, 2.33 h)	87.1° 09:20	10.3	7%	85.8°
2040-02-15 Wed	60	—	unknown	03:20–05:45 (good, 2.42 h)	87.1° 09:15	10.26	14%	91.7°
2040-02-16 Thu	62	—	unknown	03:15–05:45 (good, 2.5 h)	87.1° 09:10	10.22	22%	97.3°
2040-02-17 Fri	63	—	unknown	03:15–05:45 (good, 2.5 h)	87.1° 09:10	10.18	31%	102.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-01-19&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.