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: 12-18 (21), 12-19 (20), 12-20 (18), 01-10 (18), 01-11 (17) — by astronomy; check the weather when the night is within four days.

2035-12-18astronomy score per night — click a bar for that night2036-01-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-12-18 Tue	21	—	unknown	18:35–19:10 (good, 0.58 h)	87.1° 13:10	11.5	79%	113.1°
2035-12-19 Wed	20	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:10	11.51	69%	107.0°
2035-12-20 Thu	18	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:05	11.51	58%	100.3°
2035-12-21 Fri	16	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:00	11.51	47%	93.3°
2035-12-22 Sat	15	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 12:55	11.51	37%	86.4°
2035-12-23 Sun	13	—	unknown	18:40–18:50 (good, 0.17 h)	87.1° 12:50	11.51	28%	79.8°
2035-12-24 Mon	12	—	unknown	18:40–18:45 (good, 0.08 h)	87.1° 12:50	11.5	19%	73.7°
2035-12-25 Tue	12	—	unknown	18:40–18:45 (good, 0.08 h)	87.1° 12:45	11.5	12%	68.3°
2035-12-26 Wed	11	—	unknown	18:05–19:10 (marginal, 1.08 h)	87.1° 12:40	11.5	7%	63.8°
2035-12-27 Thu	10	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	3%	60.5°
2035-12-28 Fri	10	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:30	11.49	0%	58.6°
2035-12-29 Sat	9	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	0%	58.1°
2035-12-30 Sun	8	—	unknown	18:40–18:55 (marginal, 0.25 h)	87.1° 12:25	11.47	2%	59.2°
2035-12-31 Mon	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	5%	61.7°
2036-01-01 Tue	9	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	10%	65.4°
2036-01-02 Wed	9	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.44	16%	70.1°
2036-01-03 Thu	10	—	unknown	05:40–06:45 (marginal, 1.08 h)	87.1° 12:10	11.43	23%	75.6°
2036-01-04 Fri	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:05	11.42	32%	81.8°
2036-01-05 Sat	12	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:00	11.41	42%	88.3°
2036-01-06 Sun	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:55	11.39	52%	95.1°
2036-01-07 Mon	13	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:50	11.38	62%	101.9°
2036-01-08 Tue	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:45	11.36	73%	108.4°
2036-01-09 Wed	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:40	11.35	82%	114.2°
2036-01-10 Thu	18	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:35	11.33	90%	118.7°
2036-01-11 Fri	17	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:35	11.31	96%	121.4°
2036-01-12 Sat	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:30	11.29	100%	121.7°
2036-01-13 Sun	17	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:25	11.28	100%	119.6°
2036-01-14 Mon	17	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:20	11.26	97%	115.3°
2036-01-15 Tue	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:20	11.23	91%	109.4°
2036-01-16 Wed	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:15	11.21	83%	102.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-12-18&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.