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 3C 273: 01-02 (93), 01-03 (93), 01-04 (93), 01-05 (93), 01-06 (93) — 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	17	—	unknown	03:15–06:05 (marginal, 2.83 h)	50.2° 07:00	11.5	79%	44.8°
2035-12-19 Wed	18	—	unknown	03:05–06:05 (marginal, 3.0 h)	50.2° 07:00	11.51	69%	30.5°
2035-12-20 Thu	25	—	unknown	02:50–06:05 (marginal, 3.25 h)	50.2° 06:55	11.51	58%	16.6°
2035-12-21 Fri	34	—	unknown	04:45–06:05 (good, 1.33 h)	50.2° 06:50	11.51	47%	3.5°
2035-12-22 Sat	44	—	unknown	03:20–06:05 (good, 2.75 h)	50.2° 06:45	11.51	37%	10.1°
2035-12-23 Sun	55	—	unknown	03:05–06:10 (good, 3.08 h)	50.2° 06:40	11.51	28%	22.7°
2035-12-24 Mon	66	—	unknown	02:50–06:10 (good, 3.33 h)	50.2° 06:40	11.5	19%	35.2°
2035-12-25 Tue	75	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:35	11.5	12%	47.5°
2035-12-26 Wed	81	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:30	11.5	7%	59.6°
2035-12-27 Thu	84	—	unknown	02:40–06:10 (good, 3.5 h)	50.2° 06:25	11.49	3%	71.6°
2035-12-28 Fri	86	—	unknown	02:35–06:10 (good, 3.58 h)	50.2° 06:20	11.49	0%	83.5°
2035-12-29 Sat	86	—	unknown	02:30–06:10 (good, 3.67 h)	50.2° 06:20	11.48	0%	95.4°
2035-12-30 Sun	88	—	unknown	02:25–06:10 (good, 3.75 h)	50.2° 06:15	11.47	2%	107.2°
2035-12-31 Mon	90	—	unknown	02:25–06:10 (good, 3.75 h)	50.2° 06:10	11.46	5%	119.0°
2036-01-01 Tue	91	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 06:05	11.45	10%	130.9°
2036-01-02 Wed	93	—	unknown	02:15–06:10 (good, 3.92 h)	50.2° 06:00	11.44	16%	142.8°
2036-01-03 Thu	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.2° 06:00	11.43	23%	154.8°
2036-01-04 Fri	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.2° 05:55	11.42	32%	167.1°
2036-01-05 Sat	93	—	unknown	02:05–06:10 (good, 4.08 h)	50.2° 05:50	11.41	42%	178.5°
2036-01-06 Sun	93	—	unknown	02:00–06:10 (good, 4.17 h)	50.2° 05:45	11.39	52%	167.4°
2036-01-07 Mon	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.2° 05:45	11.38	62%	154.2°
2036-01-08 Tue	93	—	unknown	02:00–06:10 (good, 4.17 h)	50.2° 05:40	11.36	73%	140.6°
2036-01-09 Wed	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.2° 05:35	11.35	82%	126.4°
2036-01-10 Thu	93	—	unknown	02:00–06:10 (good, 4.17 h)	50.2° 05:30	11.33	90%	111.8°
2036-01-11 Fri	70	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 05:25	11.31	96%	96.8°
2036-01-12 Sat	52	—	unknown	04:05–06:10 (good, 2.08 h)	50.2° 05:25	11.29	100%	81.5°
2036-01-13 Sun	37	—	unknown	01:35–06:10 (marginal, 4.58 h)	50.2° 05:20	11.28	100%	66.2°
2036-01-14 Mon	25	—	unknown	01:50–06:10 (marginal, 4.33 h)	50.2° 05:15	11.26	97%	51.0°
2036-01-15 Tue	19	—	unknown	02:20–06:10 (marginal, 3.83 h)	50.2° 05:10	11.23	91%	36.1°
2036-01-16 Wed	20	—	unknown	01:35–06:10 (marginal, 4.58 h)	50.2° 05:05	11.21	83%	21.5°

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.