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: 12-18 (69), 12-19 (69), 12-20 (69), 12-17 (67), 12-16 (65) — by astronomy; check the weather when the night is within four days.

2045-11-25astronomy score per night — click a bar for that night2045-12-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-11-25 Sat	17	—	unknown	05:10–05:50 (good, 0.67 h)	50.1° 08:30	11.22	97%	103.1°
2045-11-26 Sun	14	—	unknown	04:20–05:50 (marginal, 1.5 h)	50.1° 08:25	11.24	93%	89.3°
2045-11-27 Mon	12	—	unknown	04:20–05:50 (marginal, 1.5 h)	50.1° 08:20	11.26	86%	75.4°
2045-11-28 Tue	11	—	unknown	04:20–05:50 (marginal, 1.5 h)	50.1° 08:20	11.28	77%	61.4°
2045-11-29 Wed	12	—	unknown	04:15–05:50 (marginal, 1.58 h)	50.1° 08:15	11.3	67%	47.4°
2045-11-30 Thu	14	—	unknown	04:05–05:50 (marginal, 1.75 h)	50.1° 08:10	11.32	56%	33.6°
2045-12-01 Fri	19	—	unknown	05:50–05:55 (good, 0.08 h)	50.1° 08:05	11.34	44%	20.4°
2045-12-02 Sat	25	—	unknown	04:35–05:55 (good, 1.33 h)	50.1° 08:05	11.35	33%	9.7°
2045-12-03 Sun	32	—	unknown	04:25–05:55 (good, 1.5 h)	50.1° 08:00	11.37	23%	12.8°
2045-12-04 Mon	38	—	unknown	04:10–05:55 (good, 1.75 h)	50.1° 07:55	11.39	14%	24.8°
2045-12-05 Tue	44	—	unknown	04:05–05:55 (good, 1.83 h)	50.1° 07:50	11.4	8%	37.8°
2045-12-06 Wed	47	—	unknown	04:00–05:55 (good, 1.92 h)	50.1° 07:45	11.41	3%	51.0°
2045-12-07 Thu	49	—	unknown	03:55–06:00 (good, 2.08 h)	50.1° 07:45	11.43	0%	64.1°
2045-12-08 Fri	51	—	unknown	03:50–06:00 (good, 2.17 h)	50.1° 07:40	11.44	0%	77.0°
2045-12-09 Sat	53	—	unknown	03:50–06:00 (good, 2.17 h)	50.1° 07:35	11.45	2%	89.7°
2045-12-10 Sun	55	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:30	11.46	6%	102.1°
2045-12-11 Mon	56	—	unknown	03:40–06:00 (good, 2.33 h)	50.1° 07:25	11.47	12%	114.2°
2045-12-12 Tue	57	—	unknown	03:35–06:00 (good, 2.42 h)	50.1° 07:25	11.47	18%	126.1°
2045-12-13 Wed	60	—	unknown	03:35–06:05 (good, 2.5 h)	50.1° 07:20	11.48	26%	137.8°
2045-12-14 Thu	62	—	unknown	03:30–06:05 (good, 2.58 h)	50.1° 07:15	11.49	35%	149.2°
2045-12-15 Fri	64	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 07:10	11.49	44%	160.2°
2045-12-16 Sat	65	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:10	11.5	54%	169.5°
2045-12-17 Sun	67	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 07:05	11.5	63%	169.3°
2045-12-18 Mon	69	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 07:00	11.5	72%	159.6°
2045-12-19 Tue	69	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 06:55	11.51	81%	147.8°
2045-12-20 Wed	69	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 06:50	11.51	88%	135.2°
2045-12-21 Thu	62	—	unknown	03:10–06:05 (good, 2.92 h)	50.1° 06:50	11.51	94%	122.0°
2045-12-22 Fri	54	—	unknown	03:20–06:10 (good, 2.83 h)	50.1° 06:45	11.51	98%	108.4°
2045-12-23 Sat	43	—	unknown	04:05–06:10 (good, 2.08 h)	50.1° 06:40	11.5	100%	94.4°
2045-12-24 Sun	33	—	unknown	05:35–06:10 (good, 0.58 h)	50.1° 06:35	11.5	99%	80.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-11-25&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.