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: 01-07 (93), 01-08 (93), 01-09 (93), 01-10 (93), 01-11 (93) — by astronomy; check the weather when the night is within four days.

2042-12-30astronomy score per night — click a bar for that night2043-01-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-12-30 Tue	17	—	unknown	02:40–06:10 (marginal, 3.5 h)	50.1° 06:15	11.47	80%	33.7°
2042-12-31 Wed	22	—	unknown	02:20–06:10 (marginal, 3.83 h)	50.1° 06:10	11.46	72%	21.3°
2043-01-01 Thu	30	—	unknown	02:00–06:10 (marginal, 4.17 h)	50.1° 06:05	11.45	62%	9.5°
2043-01-02 Fri	40	—	unknown	05:30–06:10 (good, 0.67 h)	50.1° 06:00	11.44	53%	5.3°
2043-01-03 Sat	51	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:00	11.43	44%	15.8°
2043-01-04 Sun	64	—	unknown	02:05–06:10 (good, 4.08 h)	50.1° 05:55	11.42	34%	27.4°
2043-01-05 Mon	82	—	unknown	02:05–06:10 (good, 4.08 h)	50.1° 05:50	11.4	26%	39.2°
2043-01-06 Tue	91	—	unknown	02:00–06:10 (good, 4.17 h)	50.1° 05:45	11.39	18%	51.1°
2043-01-07 Wed	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.1° 05:40	11.38	11%	63.1°
2043-01-08 Thu	93	—	unknown	01:50–06:10 (good, 4.33 h)	50.1° 05:40	11.36	6%	75.4°
2043-01-09 Fri	93	—	unknown	01:45–06:10 (good, 4.42 h)	50.1° 05:35	11.34	2%	88.0°
2043-01-10 Sat	93	—	unknown	01:45–06:10 (good, 4.42 h)	50.1° 05:30	11.33	0%	100.8°
2043-01-11 Sun	93	—	unknown	01:40–06:10 (good, 4.5 h)	50.1° 05:25	11.31	1%	113.9°
2043-01-12 Mon	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:20	11.29	3%	127.2°
2043-01-13 Tue	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:20	11.27	8%	140.7°
2043-01-14 Wed	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:15	11.25	15%	154.3°
2043-01-15 Thu	93	—	unknown	01:25–06:10 (good, 4.75 h)	50.1° 05:10	11.23	24%	167.7°
2043-01-16 Fri	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.1° 05:05	11.21	34%	175.1°
2043-01-17 Sat	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 05:05	11.18	45%	163.0°
2043-01-18 Sun	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 05:00	11.16	56%	149.1°
2043-01-19 Mon	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 04:55	11.14	67%	135.0°
2043-01-20 Tue	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 04:50	11.11	78%	120.9°
2043-01-21 Wed	93	—	unknown	01:20–06:05 (good, 4.75 h)	50.1° 04:45	11.09	86%	106.8°
2043-01-22 Thu	73	—	unknown	02:00–06:05 (good, 4.08 h)	50.1° 04:45	11.06	93%	92.8°
2043-01-23 Fri	56	—	unknown	03:50–06:05 (good, 2.25 h)	50.1° 04:40	11.03	98%	78.9°
2043-01-24 Sat	40	—	unknown	00:55–06:05 (marginal, 5.17 h)	50.1° 04:35	11.0	100%	65.2°
2043-01-25 Sun	28	—	unknown	01:10–06:05 (marginal, 4.92 h)	50.1° 04:30	10.98	99%	51.8°
2043-01-26 Mon	20	—	unknown	03:00–06:05 (marginal, 3.08 h)	50.1° 04:25	10.95	97%	38.7°
2043-01-27 Tue	17	—	unknown	03:35–06:05 (marginal, 2.5 h)	50.1° 04:25	10.92	92%	26.0°
2043-01-28 Wed	22	—	unknown	00:45–06:05 (marginal, 5.33 h)	50.1° 04:20	10.89	86%	13.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-12-30&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.