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: 12-28 (86), 12-27 (84), 12-26 (82), 12-25 (81), 12-24 (79) — by astronomy; check the weather when the night is within four days.

2038-11-29astronomy score per night — click a bar for that night2038-12-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-11-29 Mon	35	—	unknown	04:30–05:50 (good, 1.33 h)	50.1° 08:15	11.3	15%	107.9°
2038-11-30 Tue	36	—	unknown	04:25–05:50 (good, 1.42 h)	50.1° 08:10	11.31	24%	121.7°
2038-12-01 Wed	39	—	unknown	04:20–05:55 (good, 1.58 h)	50.1° 08:05	11.33	34%	135.1°
2038-12-02 Thu	40	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 08:05	11.35	44%	148.0°
2038-12-03 Fri	42	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 08:00	11.37	54%	160.5°
2038-12-04 Sat	44	—	unknown	04:10–05:55 (good, 1.75 h)	50.1° 07:55	11.38	64%	172.8°
2038-12-05 Sun	45	—	unknown	04:05–05:55 (good, 1.83 h)	50.1° 07:50	11.39	72%	175.2°
2038-12-06 Mon	46	—	unknown	04:00–05:55 (good, 1.92 h)	50.1° 07:50	11.41	80%	163.3°
2038-12-07 Tue	48	—	unknown	04:05–06:00 (good, 1.92 h)	50.1° 07:45	11.42	87%	151.4°
2038-12-08 Wed	48	—	unknown	04:00–06:00 (good, 2.0 h)	50.1° 07:40	11.43	93%	139.6°
2038-12-09 Thu	45	—	unknown	04:00–06:00 (good, 2.0 h)	50.1° 07:35	11.44	97%	127.8°
2038-12-10 Fri	42	—	unknown	04:00–06:00 (good, 2.0 h)	50.1° 07:30	11.45	99%	115.8°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-11-29&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.