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 (47), 02-04 (46), 02-02 (45), 02-05 (45), 02-01 (43) — by astronomy; check the weather when the night is within four days.

2039-01-17astronomy score per night — click a bar for that night2039-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-01-17 Mon	17	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:10	11.18	48%	79.2°
2039-01-18 Tue	20	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:05	11.16	37%	73.4°
2039-01-19 Wed	23	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 11:00	11.14	26%	68.6°
2039-01-20 Thu	27	—	unknown	05:05–06:10 (good, 1.08 h)	87.1° 10:55	11.11	17%	65.0°
2039-01-21 Fri	30	—	unknown	05:00–06:05 (good, 1.08 h)	87.1° 10:55	11.09	9%	62.9°
2039-01-22 Sat	31	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:50	11.06	4%	62.8°
2039-01-23 Sun	33	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:45	11.03	1%	64.4°
2039-01-24 Mon	34	—	unknown	04:45–06:05 (good, 1.33 h)	87.1° 10:40	11.01	0%	67.6°
2039-01-25 Tue	36	—	unknown	04:45–06:05 (good, 1.33 h)	87.1° 10:35	10.98	2%	72.0°
2039-01-26 Wed	37	—	unknown	04:40–06:05 (good, 1.42 h)	87.1° 10:35	10.95	7%	77.2°
2039-01-27 Thu	38	—	unknown	04:35–06:05 (good, 1.5 h)	87.1° 10:30	10.92	13%	82.8°
2039-01-28 Fri	39	—	unknown	04:30–06:05 (good, 1.58 h)	87.1° 10:25	10.89	20%	88.6°
2039-01-29 Sat	40	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.86	29%	94.3°
2039-01-30 Sun	41	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.83	38%	99.7°
2039-01-31 Mon	42	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:15	10.79	48%	104.6°
2039-02-01 Tue	43	—	unknown	04:15–06:00 (good, 1.75 h)	87.1° 10:10	10.76	57%	109.0°
2039-02-02 Wed	45	—	unknown	04:10–06:00 (good, 1.83 h)	87.1° 10:05	10.73	66%	112.7°
2039-02-03 Thu	47	—	unknown	04:10–06:00 (good, 1.83 h)	87.1° 10:00	10.7	75%	115.4°
2039-02-04 Fri	46	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 10:00	10.66	83%	117.0°
2039-02-05 Sat	45	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:55	10.63	89%	117.3°
2039-02-06 Sun	40	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:50	10.59	95%	116.2°
2039-02-07 Mon	38	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:45	10.56	98%	113.8°
2039-02-08 Tue	37	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:40	10.52	100%	110.0°
2039-02-09 Wed	34	—	unknown	04:10–05:50 (good, 1.67 h)	87.1° 09:40	10.48	99%	105.2°
2039-02-10 Thu	32	—	unknown	04:15–05:50 (good, 1.58 h)	87.1° 09:35	10.45	96%	99.6°
2039-02-11 Fri	30	—	unknown	04:30–05:50 (good, 1.33 h)	87.1° 09:30	10.41	91%	93.4°
2039-02-12 Sat	30	—	unknown	04:35–05:50 (good, 1.25 h)	87.1° 09:25	10.37	83%	87.0°
2039-02-13 Sun	31	—	unknown	04:15–05:45 (good, 1.5 h)	87.1° 09:25	10.33	74%	80.7°
2039-02-14 Mon	34	—	unknown	03:50–05:45 (good, 1.92 h)	87.1° 09:20	10.29	63%	74.8°
2039-02-15 Tue	39	—	unknown	03:40–05:45 (good, 2.08 h)	87.1° 09:15	10.25	52%	69.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-01-17&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.