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: 02-03 (45), 02-02 (44), 02-04 (44), 02-01 (43), 01-31 (42) — by astronomy; check the weather when the night is within four days.

2031-01-10astronomy score per night — click a bar for that night2031-02-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-01-10 Fri	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:35	11.33	96%	119.0°
2031-01-11 Sat	15	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:30	11.31	91%	115.5°
2031-01-12 Sun	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:30	11.29	84%	110.9°
2031-01-13 Mon	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:25	11.27	76%	105.2°
2031-01-14 Tue	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:20	11.25	67%	98.9°
2031-01-15 Wed	17	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:15	11.23	56%	92.0°
2031-01-16 Thu	19	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:15	11.21	46%	84.9°
2031-01-17 Fri	20	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:10	11.19	35%	77.8°
2031-01-18 Sat	23	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:05	11.16	24%	71.1°
2031-01-19 Sun	26	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:00	11.14	15%	65.3°
2031-01-20 Mon	29	—	unknown	05:05–06:10 (good, 1.08 h)	87.1° 10:55	11.11	7%	60.9°
2031-01-21 Tue	30	—	unknown	05:00–06:05 (good, 1.08 h)	87.1° 10:55	11.09	2%	58.6°
2031-01-22 Wed	31	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:50	11.06	0%	58.6°
2031-01-23 Thu	33	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:45	11.03	1%	60.9°
2031-01-24 Fri	34	—	unknown	04:45–06:05 (good, 1.33 h)	87.1° 10:40	11.01	4%	65.2°
2031-01-25 Sat	36	—	unknown	04:45–06:05 (good, 1.33 h)	87.1° 10:35	10.98	10%	70.8°
2031-01-26 Sun	37	—	unknown	04:40–06:05 (good, 1.42 h)	87.1° 10:35	10.95	18%	77.2°
2031-01-27 Mon	38	—	unknown	04:35–06:05 (good, 1.5 h)	87.1° 10:30	10.92	27%	83.9°
2031-01-28 Tue	39	—	unknown	04:30–06:05 (good, 1.58 h)	87.1° 10:25	10.89	36%	90.6°
2031-01-29 Wed	40	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.86	46%	97.2°
2031-01-30 Thu	41	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.83	56%	103.3°
2031-01-31 Fri	42	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:15	10.8	65%	108.9°
2031-02-01 Sat	43	—	unknown	04:15–06:00 (good, 1.75 h)	87.1° 10:10	10.76	74%	113.7°
2031-02-02 Sun	44	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:05	10.73	82%	117.6°
2031-02-03 Mon	45	—	unknown	04:15–06:00 (good, 1.75 h)	87.1° 10:00	10.7	88%	120.3°
2031-02-04 Tue	44	—	unknown	04:15–05:55 (good, 1.67 h)	87.1° 10:00	10.66	94%	121.7°
2031-02-05 Wed	40	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:55	10.63	97%	121.5°
2031-02-06 Thu	40	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:50	10.59	100%	119.7°
2031-02-07 Fri	39	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:45	10.56	100%	116.5°
2031-02-08 Sat	38	—	unknown	04:05–05:55 (good, 1.83 h)	87.1° 09:40	10.52	98%	112.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-01-10&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.