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: 12-19 (70), 12-18 (69), 12-17 (67), 12-16 (65), 12-15 (64) — by astronomy; check the weather when the night is within four days.

2026-11-20astronomy score per night — click a bar for that night2026-12-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-11-20 Fri	20	—	unknown	05:05–05:40 (good, 0.58 h)	50.2° 08:50	11.09	82%	171.1°
2026-11-21 Sat	22	—	unknown	05:00–05:45 (good, 0.75 h)	50.2° 08:45	11.12	90%	160.8°
2026-11-22 Sun	20	—	unknown	05:05–05:45 (good, 0.67 h)	50.2° 08:45	11.14	96%	147.3°
2026-11-23 Mon	20	—	unknown	05:00–05:45 (good, 0.75 h)	50.2° 08:40	11.17	99%	133.0°
2026-11-24 Tue	20	—	unknown	05:00–05:45 (good, 0.75 h)	50.2° 08:35	11.19	100%	118.3°
2026-11-25 Wed	17	—	unknown	05:10–05:45 (good, 0.58 h)	50.2° 08:30	11.21	97%	103.4°
2026-11-26 Thu	14	—	unknown	04:20–05:50 (marginal, 1.5 h)	50.2° 08:25	11.23	92%	88.5°
2026-11-27 Fri	12	—	unknown	04:20–05:50 (marginal, 1.5 h)	50.2° 08:25	11.26	84%	73.8°
2026-11-28 Sat	11	—	unknown	04:20–05:50 (marginal, 1.5 h)	50.2° 08:20	11.28	75%	59.3°
2026-11-29 Sun	12	—	unknown	04:15–05:50 (marginal, 1.58 h)	50.2° 08:15	11.3	65%	45.3°
2026-11-30 Mon	14	—	unknown	04:05–05:50 (marginal, 1.75 h)	50.2° 08:10	11.31	54%	31.8°
2026-12-01 Tue	20	—	unknown	05:35–05:55 (good, 0.33 h)	50.2° 08:05	11.33	43%	19.1°
2026-12-02 Wed	25	—	unknown	04:35–05:55 (good, 1.33 h)	50.2° 08:05	11.35	33%	9.2°
2026-12-03 Thu	32	—	unknown	04:25–05:55 (good, 1.5 h)	50.2° 08:00	11.36	23%	11.9°
2026-12-04 Fri	38	—	unknown	04:15–05:55 (good, 1.67 h)	50.2° 07:55	11.38	16%	22.7°
2026-12-05 Sat	43	—	unknown	04:05–05:55 (good, 1.83 h)	50.2° 07:50	11.39	9%	34.6°
2026-12-06 Sun	47	—	unknown	04:00–05:55 (good, 1.92 h)	50.2° 07:45	11.41	4%	46.5°
2026-12-07 Mon	49	—	unknown	03:55–06:00 (good, 2.08 h)	50.2° 07:45	11.42	1%	58.5°
2026-12-08 Tue	51	—	unknown	03:55–06:00 (good, 2.08 h)	50.2° 07:40	11.43	0%	70.3°
2026-12-09 Wed	53	—	unknown	03:50–06:00 (good, 2.17 h)	50.2° 07:35	11.44	1%	82.1°
2026-12-10 Thu	55	—	unknown	03:45–06:00 (good, 2.25 h)	50.2° 07:30	11.45	3%	93.8°
2026-12-11 Fri	56	—	unknown	03:40–06:00 (good, 2.33 h)	50.2° 07:30	11.46	7%	105.5°
2026-12-12 Sat	57	—	unknown	03:35–06:00 (good, 2.42 h)	50.2° 07:25	11.47	13%	117.2°
2026-12-13 Sun	59	—	unknown	03:35–06:00 (good, 2.42 h)	50.2° 07:20	11.48	20%	128.9°
2026-12-14 Mon	62	—	unknown	03:30–06:05 (good, 2.58 h)	50.2° 07:15	11.49	28%	140.6°
2026-12-15 Tue	64	—	unknown	03:25–06:05 (good, 2.67 h)	50.2° 07:10	11.49	37%	152.4°
2026-12-16 Wed	65	—	unknown	03:20–06:05 (good, 2.75 h)	50.2° 07:10	11.5	47%	163.8°
2026-12-17 Thu	67	—	unknown	03:15–06:05 (good, 2.83 h)	50.2° 07:05	11.5	57%	171.6°
2026-12-18 Fri	69	—	unknown	03:15–06:05 (good, 2.83 h)	50.2° 07:00	11.5	67%	165.5°
2026-12-19 Sat	70	—	unknown	03:15–06:05 (good, 2.83 h)	50.2° 06:55	11.51	77%	153.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-11-20&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.