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: 12-12 (56), 12-11 (55), 12-13 (55), 12-10 (54), 12-09 (53) — by astronomy; check the weather when the night is within four days.

2043-11-18astronomy score per night — click a bar for that night2043-12-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-11-18 Wed	9	—	unknown	04:45–06:15 (marginal, 1.5 h)	50.1° 09:00	11.04	94%	100.3°
2043-11-19 Thu	8	—	unknown	04:50–05:40 (marginal, 0.83 h)	50.1° 08:55	11.07	87%	85.4°
2043-11-20 Fri	8	—	unknown	04:50–05:40 (marginal, 0.83 h)	50.1° 08:50	11.09	78%	70.9°
2043-11-21 Sat	8	—	unknown	04:45–05:45 (marginal, 1.0 h)	50.1° 08:50	11.12	68%	56.9°
2043-11-22 Sun	9	—	unknown	04:40–05:45 (marginal, 1.08 h)	50.1° 08:45	11.14	57%	43.3°
2043-11-23 Mon	11	—	unknown	04:30–05:45 (marginal, 1.25 h)	50.1° 08:40	11.16	46%	30.2°
2043-11-24 Tue	15	—	unknown	05:15–05:45 (good, 0.5 h)	50.1° 08:35	11.19	36%	17.8°
2043-11-25 Wed	19	—	unknown	05:00–05:45 (good, 0.75 h)	50.1° 08:30	11.21	27%	7.0°
2043-11-26 Thu	24	—	unknown	04:50–05:50 (good, 1.0 h)	50.1° 08:30	11.23	19%	9.6°
2043-11-27 Fri	27	—	unknown	04:40–05:50 (good, 1.17 h)	50.1° 08:25	11.25	12%	20.8°
2043-11-28 Sat	32	—	unknown	04:35–05:50 (good, 1.25 h)	50.1° 08:20	11.27	6%	32.5°
2043-11-29 Sun	34	—	unknown	04:30–05:50 (good, 1.33 h)	50.1° 08:15	11.29	3%	44.2°
2043-11-30 Mon	36	—	unknown	04:25–05:50 (good, 1.42 h)	50.1° 08:10	11.31	1%	56.0°
2043-12-01 Tue	38	—	unknown	04:20–05:55 (good, 1.58 h)	50.1° 08:10	11.33	0%	67.7°
2043-12-02 Wed	39	—	unknown	04:20–05:55 (good, 1.58 h)	50.1° 08:05	11.35	2%	79.5°
2043-12-03 Thu	42	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 08:00	11.36	5%	91.3°
2043-12-04 Fri	43	—	unknown	04:10–05:55 (good, 1.75 h)	50.1° 07:55	11.38	10%	103.2°
2043-12-05 Sat	44	—	unknown	04:05–05:55 (good, 1.83 h)	50.1° 07:55	11.39	16%	115.2°
2043-12-06 Sun	46	—	unknown	04:00–05:55 (good, 1.92 h)	50.1° 07:50	11.41	24%	127.3°
2043-12-07 Mon	49	—	unknown	04:00–06:00 (good, 2.0 h)	50.1° 07:45	11.42	33%	139.6°
2043-12-08 Tue	50	—	unknown	03:55–06:00 (good, 2.08 h)	50.1° 07:40	11.43	42%	152.1°
2043-12-09 Wed	53	—	unknown	03:50–06:00 (good, 2.17 h)	50.1° 07:35	11.44	53%	164.6°
2043-12-10 Thu	54	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:35	11.45	64%	174.3°
2043-12-11 Fri	55	—	unknown	03:40–06:00 (good, 2.33 h)	50.1° 07:30	11.46	74%	165.8°
2043-12-12 Sat	56	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:25	11.47	83%	152.0°
2043-12-13 Sun	55	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:20	11.48	91%	137.5°
2043-12-14 Mon	51	—	unknown	03:40–06:05 (good, 2.42 h)	50.1° 07:15	11.49	97%	122.5°
2043-12-15 Tue	42	—	unknown	03:50–06:05 (good, 2.25 h)	50.1° 07:15	11.49	100%	107.3°
2043-12-16 Wed	34	—	unknown	04:50–06:05 (good, 1.25 h)	50.1° 07:10	11.5	99%	92.1°
2043-12-17 Thu	25	—	unknown	03:10–06:05 (marginal, 2.92 h)	50.1° 07:05	11.5	96%	77.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-11-18&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.