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.

2038-12-11astronomy score per night — click a bar for that night2039-01-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-11 Sat	36	—	unknown	04:05–06:00 (good, 1.92 h)	50.1° 07:30	11.46	100%	103.8°
2038-12-12 Sun	29	—	unknown	05:00–06:00 (good, 1.0 h)	50.1° 07:25	11.47	99%	91.6°
2038-12-13 Mon	24	—	unknown	03:20–06:00 (marginal, 2.67 h)	50.1° 07:20	11.48	96%	79.3°
2038-12-14 Tue	20	—	unknown	03:25–06:05 (marginal, 2.67 h)	50.1° 07:15	11.49	90%	66.8°
2038-12-15 Wed	17	—	unknown	03:25–06:05 (marginal, 2.67 h)	50.1° 07:10	11.49	84%	54.1°
2038-12-16 Thu	16	—	unknown	03:25–06:05 (marginal, 2.67 h)	50.1° 07:10	11.5	75%	41.2°
2038-12-17 Fri	18	—	unknown	03:10–06:05 (marginal, 2.92 h)	50.1° 07:05	11.5	66%	28.1°
2038-12-18 Sat	25	—	unknown	02:55–06:05 (marginal, 3.17 h)	50.1° 07:00	11.5	55%	14.7°
2038-12-19 Sun	35	—	unknown	04:00–06:05 (good, 2.08 h)	50.1° 06:55	11.51	44%	1.0°
2038-12-20 Mon	46	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 06:55	11.51	33%	13.2°
2038-12-21 Tue	57	—	unknown	03:00–06:05 (good, 3.08 h)	50.1° 06:50	11.51	23%	27.5°
2038-12-22 Wed	69	—	unknown	03:00–06:10 (good, 3.17 h)	50.1° 06:45	11.51	14%	42.2°
2038-12-23 Thu	76	—	unknown	02:55–06:10 (good, 3.25 h)	50.1° 06:40	11.51	6%	57.0°
2038-12-24 Fri	79	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:35	11.5	2%	72.0°
2038-12-25 Sat	81	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 06:35	11.5	0%	86.8°
2038-12-26 Sun	82	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 06:30	11.5	1%	101.5°
2038-12-27 Mon	84	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 06:25	11.49	5%	115.8°
2038-12-28 Tue	86	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:20	11.48	11%	129.7°
2038-12-29 Wed	87	—	unknown	02:30–06:10 (good, 3.67 h)	50.1° 06:15	11.48	18%	143.2°
2038-12-30 Thu	88	—	unknown	02:25–06:10 (good, 3.75 h)	50.1° 06:15	11.47	27%	156.2°
2038-12-31 Fri	90	—	unknown	02:25–06:10 (good, 3.75 h)	50.1° 06:10	11.46	37%	168.9°
2039-01-01 Sat	91	—	unknown	02:20–06:10 (good, 3.83 h)	50.1° 06:05	11.45	46%	178.7°
2039-01-02 Sun	93	—	unknown	02:15–06:10 (good, 3.92 h)	50.1° 06:00	11.44	56%	166.7°
2039-01-03 Mon	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.1° 06:00	11.43	65%	154.8°
2039-01-04 Tue	93	—	unknown	02:15–06:10 (good, 3.92 h)	50.1° 05:55	11.42	74%	143.0°
2039-01-05 Wed	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.1° 05:50	11.4	82%	131.2°
2039-01-06 Thu	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.1° 05:45	11.39	88%	119.3°
2039-01-07 Fri	86	—	unknown	02:15–06:10 (good, 3.92 h)	50.1° 05:40	11.38	94%	107.3°
2039-01-08 Sat	63	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 05:40	11.36	98%	95.1°
2039-01-09 Sun	49	—	unknown	04:15–06:10 (good, 1.92 h)	50.1° 05:35	11.34	100%	82.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-11&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.