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: 12-31 (90), 12-30 (88), 12-29 (86), 12-28 (85), 12-27 (82) — by astronomy; check the weather when the night is within four days.

2043-12-02astronomy score per night — click a bar for that night2043-12-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-12-02 Wed	39	—	unknown	04:20–05:55 (good, 1.58 h)	50.1° 08:05	11.35	2%	79.5°
2043-12-03 Thu	42	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 08:00	11.36	5%	91.3°
2043-12-04 Fri	43	—	unknown	04:10–05:55 (good, 1.75 h)	50.1° 07:55	11.38	10%	103.2°
2043-12-05 Sat	44	—	unknown	04:05–05:55 (good, 1.83 h)	50.1° 07:55	11.39	16%	115.2°
2043-12-06 Sun	46	—	unknown	04:00–05:55 (good, 1.92 h)	50.1° 07:50	11.41	24%	127.3°
2043-12-07 Mon	49	—	unknown	04:00–06:00 (good, 2.0 h)	50.1° 07:45	11.42	33%	139.6°
2043-12-08 Tue	50	—	unknown	03:55–06:00 (good, 2.08 h)	50.1° 07:40	11.43	42%	152.1°
2043-12-09 Wed	53	—	unknown	03:50–06:00 (good, 2.17 h)	50.1° 07:35	11.44	53%	164.6°
2043-12-10 Thu	54	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:35	11.45	64%	174.3°
2043-12-11 Fri	55	—	unknown	03:40–06:00 (good, 2.33 h)	50.1° 07:30	11.46	74%	165.8°
2043-12-12 Sat	56	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:25	11.47	83%	152.0°
2043-12-13 Sun	55	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:20	11.48	91%	137.5°
2043-12-14 Mon	51	—	unknown	03:40–06:05 (good, 2.42 h)	50.1° 07:15	11.49	97%	122.5°
2043-12-15 Tue	42	—	unknown	03:50–06:05 (good, 2.25 h)	50.1° 07:15	11.49	100%	107.3°
2043-12-16 Wed	34	—	unknown	04:50–06:05 (good, 1.25 h)	50.1° 07:10	11.5	99%	92.1°
2043-12-17 Thu	25	—	unknown	03:10–06:05 (marginal, 2.92 h)	50.1° 07:05	11.5	96%	77.1°
2043-12-18 Fri	20	—	unknown	03:15–06:05 (marginal, 2.83 h)	50.1° 07:00	11.5	90%	62.4°
2043-12-19 Sat	17	—	unknown	03:15–06:05 (marginal, 2.83 h)	50.1° 07:00	11.51	82%	48.2°
2043-12-20 Sun	17	—	unknown	03:10–06:05 (marginal, 2.92 h)	50.1° 06:55	11.51	73%	34.4°
2043-12-21 Mon	22	—	unknown	02:50–06:05 (marginal, 3.25 h)	50.1° 06:50	11.51	63%	21.4°
2043-12-22 Tue	31	—	unknown	02:35–06:05 (marginal, 3.5 h)	50.1° 06:45	11.51	53%	9.6°
2043-12-23 Wed	41	—	unknown	03:20–06:10 (good, 2.83 h)	50.1° 06:40	11.51	43%	7.5°
2043-12-24 Thu	51	—	unknown	03:05–06:10 (good, 3.08 h)	50.1° 06:40	11.5	33%	18.0°
2043-12-25 Fri	63	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 06:35	11.5	25%	29.7°
2043-12-26 Sat	74	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 06:30	11.5	17%	41.4°
2043-12-27 Sun	82	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 06:25	11.49	11%	53.1°
2043-12-28 Mon	85	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:20	11.49	6%	64.8°
2043-12-29 Tue	86	—	unknown	02:30–06:10 (good, 3.67 h)	50.1° 06:20	11.48	2%	76.6°
2043-12-30 Wed	88	—	unknown	02:30–06:10 (good, 3.67 h)	50.1° 06:15	11.47	0%	88.4°
2043-12-31 Thu	90	—	unknown	02:25–06:10 (good, 3.75 h)	50.1° 06:10	11.46	0%	100.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-12-02&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.