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: 01-11 (93), 01-12 (93), 01-13 (93), 01-14 (93), 01-15 (93) — by astronomy; check the weather when the night is within four days.

2047-12-19astronomy score per night — click a bar for that night2048-01-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-12-19 Thu	69	—	unknown	03:10–06:05 (good, 2.92 h)	50.1° 07:00	11.51	12%	121.5°
2047-12-20 Fri	71	—	unknown	03:05–06:05 (good, 3.0 h)	50.1° 06:55	11.51	20%	134.9°
2047-12-21 Sat	73	—	unknown	03:05–06:05 (good, 3.0 h)	50.1° 06:50	11.51	29%	147.7°
2047-12-22 Sun	74	—	unknown	03:00–06:05 (good, 3.08 h)	50.1° 06:45	11.51	39%	159.5°
2047-12-23 Mon	77	—	unknown	02:55–06:10 (good, 3.25 h)	50.1° 06:40	11.51	48%	168.5°
2047-12-24 Tue	78	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:40	11.5	58%	167.9°
2047-12-25 Wed	80	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:35	11.5	68%	158.9°
2047-12-26 Thu	81	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:30	11.5	76%	148.0°
2047-12-27 Fri	81	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:25	11.49	84%	136.7°
2047-12-28 Sat	79	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 06:20	11.49	90%	125.1°
2047-12-29 Sun	69	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:20	11.48	95%	113.5°
2047-12-30 Mon	59	—	unknown	02:55–06:10 (good, 3.25 h)	50.1° 06:15	11.47	98%	101.7°
2047-12-31 Tue	48	—	unknown	04:00–06:10 (good, 2.17 h)	50.1° 06:10	11.46	100%	89.7°
2048-01-01 Wed	38	—	unknown	05:25–06:10 (good, 0.75 h)	50.1° 06:05	11.45	100%	77.6°
2048-01-02 Thu	30	—	unknown	02:20–06:10 (marginal, 3.83 h)	50.1° 06:05	11.44	97%	65.3°
2048-01-03 Fri	24	—	unknown	02:25–06:10 (marginal, 3.75 h)	50.1° 06:00	11.43	93%	52.9°
2048-01-04 Sat	20	—	unknown	02:25–06:10 (marginal, 3.75 h)	50.1° 05:55	11.42	87%	40.4°
2048-01-05 Sun	21	—	unknown	02:10–06:10 (marginal, 4.0 h)	50.1° 05:50	11.41	79%	28.0°
2048-01-06 Mon	28	—	unknown	01:50–06:10 (marginal, 4.33 h)	50.1° 05:45	11.39	70%	16.4°
2048-01-07 Tue	39	—	unknown	01:30–06:10 (marginal, 4.67 h)	50.1° 05:45	11.38	59%	10.1°
2048-01-08 Wed	52	—	unknown	02:20–06:10 (good, 3.83 h)	50.1° 05:40	11.36	48%	17.5°
2048-01-09 Thu	74	—	unknown	01:50–06:10 (good, 4.33 h)	50.1° 05:35	11.35	37%	30.0°
2048-01-10 Fri	88	—	unknown	01:45–06:10 (good, 4.42 h)	50.1° 05:30	11.33	26%	43.6°
2048-01-11 Sat	93	—	unknown	01:40–06:10 (good, 4.5 h)	50.1° 05:25	11.31	17%	57.8°
2048-01-12 Sun	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:25	11.29	9%	72.2°
2048-01-13 Mon	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:20	11.27	3%	86.7°
2048-01-14 Tue	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:15	11.25	0%	101.1°
2048-01-15 Wed	93	—	unknown	01:25–06:10 (good, 4.75 h)	50.1° 05:10	11.23	0%	115.3°
2048-01-16 Thu	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.1° 05:10	11.21	3%	129.2°
2048-01-17 Fri	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 05:05	11.19	8%	142.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-12-19&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.