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: 01-28 (39), 01-27 (38), 01-26 (37), 01-25 (36), 01-23 (34) — by astronomy; check the weather when the night is within four days.

2037-01-03astronomy score per night — click a bar for that night2037-02-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-01-03 Sat	8	—	unknown	05:35–06:10 (marginal, 0.58 h)	87.1° 12:05	11.42	95%	115.6°
2037-01-04 Sun	8	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 12:00	11.41	89%	110.4°
2037-01-05 Mon	8	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 11:55	11.4	80%	104.0°
2037-01-06 Tue	9	—	unknown	05:25–06:10 (marginal, 0.75 h)	87.1° 11:50	11.38	70%	97.0°
2037-01-07 Wed	10	—	unknown	05:20–06:10 (marginal, 0.83 h)	87.1° 11:45	11.37	59%	89.8°
2037-01-08 Thu	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:40	11.35	48%	82.8°
2037-01-09 Fri	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:40	11.34	37%	76.3°
2037-01-10 Sat	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:35	11.32	27%	70.5°
2037-01-11 Sun	17	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:30	11.3	19%	65.6°
2037-01-12 Mon	20	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:25	11.28	11%	62.1°
2037-01-13 Tue	22	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:20	11.26	6%	59.9°
2037-01-14 Wed	23	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.24	2%	59.3°
2037-01-15 Thu	24	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.22	0%	60.3°
2037-01-16 Fri	25	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 11:10	11.2	0%	62.7°
2037-01-17 Sat	27	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:05	11.17	2%	66.3°
2037-01-18 Sun	28	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:05	11.15	6%	70.8°
2037-01-19 Mon	29	—	unknown	05:05–06:10 (good, 1.08 h)	87.1° 11:00	11.12	11%	76.1°
2037-01-20 Tue	30	—	unknown	05:00–06:10 (good, 1.17 h)	87.1° 10:55	11.1	17%	81.7°
2037-01-21 Wed	31	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:50	11.07	25%	87.7°
2037-01-22 Thu	32	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:45	11.05	34%	93.8°
2037-01-23 Fri	34	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:45	11.02	43%	99.8°
2037-01-24 Sat	34	—	unknown	04:45–06:05 (good, 1.33 h)	87.1° 10:40	10.99	53%	105.7°
2037-01-25 Sun	36	—	unknown	04:40–06:05 (good, 1.42 h)	87.1° 10:35	10.96	63%	111.1°
2037-01-26 Mon	37	—	unknown	04:35–06:05 (good, 1.5 h)	87.1° 10:30	10.93	73%	115.6°
2037-01-27 Tue	38	—	unknown	04:35–06:05 (good, 1.5 h)	87.1° 10:25	10.9	82%	118.9°
2037-01-28 Wed	39	—	unknown	04:35–06:05 (good, 1.5 h)	87.1° 10:25	10.87	90%	120.6°
2037-01-29 Thu	34	—	unknown	04:35–06:00 (good, 1.42 h)	87.1° 10:20	10.84	96%	120.1°
2037-01-30 Fri	33	—	unknown	04:35–06:00 (good, 1.42 h)	87.1° 10:15	10.81	99%	117.4°
2037-01-31 Sat	31	—	unknown	04:35–06:00 (good, 1.42 h)	87.1° 10:10	10.78	100%	112.8°
2037-02-01 Sun	29	—	unknown	04:40–06:00 (good, 1.33 h)	87.1° 10:10	10.75	97%	106.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-01-03&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.