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.

2042-12-13astronomy score per night — click a bar for that night2043-01-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-12-13 Sat	59	—	unknown	03:35–06:00 (good, 2.42 h)	50.1° 07:20	11.48	2%	91.8°
2042-12-14 Sun	62	—	unknown	03:30–06:05 (good, 2.58 h)	50.1° 07:15	11.49	6%	104.6°
2042-12-15 Mon	64	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 07:10	11.49	11%	117.5°
2042-12-16 Tue	65	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:10	11.5	19%	130.6°
2042-12-17 Wed	67	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:05	11.5	28%	143.9°
2042-12-18 Thu	69	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 07:00	11.5	38%	157.3°
2042-12-19 Fri	70	—	unknown	03:10–06:05 (good, 2.92 h)	50.1° 06:55	11.51	49%	170.6°
2042-12-20 Sat	71	—	unknown	03:05–06:05 (good, 3.0 h)	50.1° 06:55	11.51	60%	173.2°
2042-12-21 Sun	73	—	unknown	03:00–06:05 (good, 3.08 h)	50.1° 06:50	11.51	71%	159.9°
2042-12-22 Mon	74	—	unknown	03:05–06:10 (good, 3.08 h)	50.1° 06:45	11.51	81%	145.6°
2042-12-23 Tue	73	—	unknown	03:05–06:10 (good, 3.08 h)	50.1° 06:40	11.51	89%	131.1°
2042-12-24 Wed	64	—	unknown	03:05–06:10 (good, 3.08 h)	50.1° 06:35	11.5	95%	116.5°
2042-12-25 Thu	52	—	unknown	03:15–06:10 (good, 2.92 h)	50.1° 06:35	11.5	99%	102.0°
2042-12-26 Fri	40	—	unknown	04:40–06:10 (good, 1.5 h)	50.1° 06:30	11.5	100%	87.6°
2042-12-27 Sat	30	—	unknown	02:35–06:10 (marginal, 3.58 h)	50.1° 06:25	11.49	98%	73.6°
2042-12-28 Sun	23	—	unknown	02:40–06:10 (marginal, 3.5 h)	50.1° 06:20	11.48	94%	59.9°
2042-12-29 Mon	19	—	unknown	02:45–06:10 (marginal, 3.42 h)	50.1° 06:15	11.48	88%	46.6°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-12-13&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.