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: 01-01 (92), 01-02 (92), 01-03 (92), 01-18 (92), 12-31 (90) — by astronomy; check the weather when the night is within four days.

2030-12-20astronomy score per night — click a bar for that night2031-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-12-20 Fri	60	—	unknown	03:05–06:05 (good, 3.0 h)	50.2° 06:50	11.51	20%	31.2°
2030-12-21 Sat	69	—	unknown	03:00–06:05 (good, 3.08 h)	50.2° 06:50	11.51	11%	45.2°
2030-12-22 Sun	76	—	unknown	03:00–06:10 (good, 3.17 h)	50.2° 06:45	11.51	5%	59.9°
2030-12-23 Mon	77	—	unknown	02:55–06:10 (good, 3.25 h)	50.2° 06:40	11.51	1%	74.8°
2030-12-24 Tue	79	—	unknown	02:50–06:10 (good, 3.33 h)	50.2° 06:35	11.5	0%	89.9°
2030-12-25 Wed	81	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:35	11.5	2%	104.9°
2030-12-26 Thu	83	—	unknown	02:40–06:10 (good, 3.5 h)	50.2° 06:30	11.5	7%	119.6°
2030-12-27 Fri	84	—	unknown	02:40–06:10 (good, 3.5 h)	50.2° 06:25	11.49	14%	133.9°
2030-12-28 Sat	86	—	unknown	02:35–06:10 (good, 3.58 h)	50.2° 06:20	11.48	23%	147.5°
2030-12-29 Sun	88	—	unknown	02:30–06:10 (good, 3.67 h)	50.2° 06:15	11.48	33%	160.1°
2030-12-30 Mon	88	—	unknown	02:25–06:10 (good, 3.75 h)	50.2° 06:15	11.47	44%	169.6°
2030-12-31 Tue	90	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 06:10	11.46	54%	167.6°
2031-01-01 Wed	92	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 06:05	11.45	64%	157.4°
2031-01-02 Thu	92	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 06:00	11.44	72%	146.0°
2031-01-03 Fri	92	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 05:55	11.43	81%	134.4°
2031-01-04 Sat	90	—	unknown	02:15–06:10 (good, 3.92 h)	50.2° 05:55	11.42	88%	122.8°
2031-01-05 Sun	86	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 05:50	11.4	93%	111.1°
2031-01-06 Mon	66	—	unknown	02:30–06:10 (good, 3.67 h)	50.2° 05:45	11.39	97%	99.5°
2031-01-07 Tue	55	—	unknown	03:35–06:10 (good, 2.58 h)	50.2° 05:40	11.38	99%	87.8°
2031-01-08 Wed	43	—	unknown	05:00–06:10 (good, 1.17 h)	50.2° 05:40	11.36	100%	76.0°
2031-01-09 Thu	34	—	unknown	01:50–06:10 (marginal, 4.33 h)	50.2° 05:35	11.34	99%	64.1°
2031-01-10 Fri	26	—	unknown	01:55–06:10 (marginal, 4.25 h)	50.2° 05:30	11.33	96%	52.2°
2031-01-11 Sat	22	—	unknown	02:00–06:10 (marginal, 4.17 h)	50.2° 05:25	11.31	91%	40.2°
2031-01-12 Sun	21	—	unknown	01:50–06:10 (marginal, 4.33 h)	50.2° 05:20	11.29	84%	28.3°
2031-01-13 Mon	27	—	unknown	01:25–06:10 (marginal, 4.75 h)	50.2° 05:20	11.27	76%	16.9°
2031-01-14 Tue	36	—	unknown	01:10–06:10 (marginal, 5.0 h)	50.2° 05:15	11.25	67%	9.3°
2031-01-15 Wed	48	—	unknown	03:35–05:30 (good, 1.92 h)	50.2° 05:10	11.23	56%	15.0°
2031-01-16 Thu	65	—	unknown	01:40–06:10 (good, 4.5 h)	50.2° 05:05	11.21	46%	26.9°
2031-01-17 Fri	86	—	unknown	01:15–06:10 (good, 4.92 h)	50.2° 05:00	11.19	35%	40.2°
2031-01-18 Sat	92	—	unknown	01:10–06:10 (good, 5.0 h)	50.2° 05:00	11.16	24%	54.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-12-20&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.