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: 12-23 (76), 12-24 (75), 12-25 (75), 12-22 (74), 12-21 (73) — by astronomy; check the weather when the night is within four days.

2031-11-30astronomy score per night — click a bar for that night2031-12-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-11-30 Sun	20	—	unknown	05:15–05:50 (good, 0.58 h)	50.2° 08:10	11.31	96%	95.6°
2031-12-01 Mon	17	—	unknown	04:05–05:55 (marginal, 1.83 h)	50.2° 08:10	11.33	92%	83.7°
2031-12-02 Tue	15	—	unknown	04:05–05:55 (marginal, 1.83 h)	50.2° 08:05	11.34	86%	71.9°
2031-12-03 Wed	14	—	unknown	04:05–05:55 (marginal, 1.83 h)	50.2° 08:00	11.36	79%	60.2°
2031-12-04 Thu	14	—	unknown	04:00–05:55 (marginal, 1.92 h)	50.2° 07:55	11.38	70%	48.6°
2031-12-05 Fri	16	—	unknown	03:50–05:55 (marginal, 2.08 h)	50.2° 07:50	11.39	62%	37.0°
2031-12-06 Sat	19	—	unknown	03:40–05:55 (marginal, 2.25 h)	50.2° 07:50	11.4	52%	25.5°
2031-12-07 Sun	25	—	unknown	04:45–06:00 (good, 1.25 h)	50.2° 07:45	11.42	42%	14.6°
2031-12-08 Mon	32	—	unknown	04:15–06:00 (good, 1.75 h)	50.2° 07:40	11.43	33%	8.3°
2031-12-09 Tue	40	—	unknown	04:00–06:00 (good, 2.0 h)	50.2° 07:35	11.44	23%	15.7°
2031-12-10 Wed	47	—	unknown	03:45–06:00 (good, 2.25 h)	50.2° 07:35	11.45	15%	27.9°
2031-12-11 Thu	53	—	unknown	03:40–06:00 (good, 2.33 h)	50.2° 07:30	11.46	8%	41.2°
2031-12-12 Fri	57	—	unknown	03:40–06:00 (good, 2.33 h)	50.2° 07:25	11.47	3%	55.1°
2031-12-13 Sat	59	—	unknown	03:35–06:00 (good, 2.42 h)	50.2° 07:20	11.48	0%	69.5°
2031-12-14 Sun	62	—	unknown	03:30–06:05 (good, 2.58 h)	50.2° 07:15	11.48	0%	84.2°
2031-12-15 Mon	62	—	unknown	03:25–06:05 (good, 2.67 h)	50.2° 07:15	11.49	4%	99.0°
2031-12-16 Tue	65	—	unknown	03:20–06:05 (good, 2.75 h)	50.2° 07:10	11.5	10%	113.8°
2031-12-17 Wed	67	—	unknown	03:20–06:05 (good, 2.75 h)	50.2° 07:05	11.5	18%	128.4°
2031-12-18 Thu	68	—	unknown	03:15–06:05 (good, 2.83 h)	50.2° 07:00	11.5	27%	142.6°
2031-12-19 Fri	70	—	unknown	03:10–06:05 (good, 2.92 h)	50.2° 06:55	11.51	38%	156.2°
2031-12-20 Sat	71	—	unknown	03:05–06:05 (good, 3.0 h)	50.2° 06:55	11.51	49%	168.2°
2031-12-21 Sun	73	—	unknown	03:05–06:05 (good, 3.0 h)	50.2° 06:50	11.51	60%	170.3°
2031-12-22 Mon	74	—	unknown	03:00–06:05 (good, 3.08 h)	50.2° 06:45	11.51	70%	160.0°
2031-12-23 Tue	76	—	unknown	03:00–06:10 (good, 3.17 h)	50.2° 06:40	11.51	79%	147.9°
2031-12-24 Wed	75	—	unknown	03:00–06:10 (good, 3.17 h)	50.2° 06:40	11.5	87%	135.5°
2031-12-25 Thu	75	—	unknown	02:55–06:10 (good, 3.25 h)	50.2° 06:35	11.5	93%	123.2°
2031-12-26 Fri	63	—	unknown	03:00–06:10 (good, 3.17 h)	50.2° 06:30	11.5	97%	111.0°
2031-12-27 Sat	54	—	unknown	03:15–06:10 (good, 2.92 h)	50.2° 06:25	11.49	99%	99.0°
2031-12-28 Sun	44	—	unknown	04:25–06:10 (good, 1.75 h)	50.2° 06:20	11.49	100%	87.0°
2031-12-29 Mon	35	—	unknown	05:40–06:10 (good, 0.5 h)	50.2° 06:20	11.48	98%	75.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-11-30&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.