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

2030-12-03astronomy score per night — click a bar for that night2031-01-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-12-03 Tue	42	—	unknown	04:10–05:55 (good, 1.75 h)	50.2° 08:00	11.36	70%	170.5°
2030-12-04 Wed	44	—	unknown	04:10–05:55 (good, 1.75 h)	50.2° 07:55	11.38	78%	165.2°
2030-12-05 Thu	45	—	unknown	04:10–05:55 (good, 1.75 h)	50.2° 07:50	11.39	86%	154.6°
2030-12-06 Fri	45	—	unknown	04:10–05:55 (good, 1.75 h)	50.2° 07:50	11.41	92%	143.2°
2030-12-07 Sat	41	—	unknown	04:05–06:00 (good, 1.92 h)	50.2° 07:45	11.42	96%	131.6°
2030-12-08 Sun	41	—	unknown	04:05–06:00 (good, 1.92 h)	50.2° 07:40	11.43	99%	119.9°
2030-12-09 Mon	37	—	unknown	04:10–06:00 (good, 1.83 h)	50.2° 07:35	11.44	100%	108.2°
2030-12-10 Tue	31	—	unknown	04:35–06:00 (good, 1.42 h)	50.2° 07:30	11.45	99%	96.5°
2030-12-11 Wed	25	—	unknown	05:35–06:00 (good, 0.42 h)	50.2° 07:30	11.46	96%	84.8°
2030-12-12 Thu	21	—	unknown	03:25–06:00 (marginal, 2.58 h)	50.2° 07:25	11.47	92%	73.1°
2030-12-13 Fri	18	—	unknown	03:30–06:00 (marginal, 2.5 h)	50.2° 07:20	11.48	86%	61.3°
2030-12-14 Sat	18	—	unknown	03:25–06:05 (marginal, 2.67 h)	50.2° 07:15	11.49	79%	49.5°
2030-12-15 Sun	18	—	unknown	03:20–06:05 (marginal, 2.75 h)	50.2° 07:10	11.49	70%	37.5°
2030-12-16 Mon	22	—	unknown	03:05–06:05 (marginal, 3.0 h)	50.2° 07:10	11.5	61%	25.6°
2030-12-17 Tue	30	—	unknown	05:55–06:05 (good, 0.17 h)	50.2° 07:05	11.5	51%	14.5°
2030-12-18 Wed	39	—	unknown	03:40–06:05 (good, 2.42 h)	50.2° 07:00	11.5	40%	9.6°
2030-12-19 Thu	49	—	unknown	03:25–06:05 (good, 2.67 h)	50.2° 06:55	11.51	30%	18.3°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-12-03&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.