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: 11-10 (4), 11-09 (3), 11-07 (2), 11-08 (2), 11-05 (1) — by astronomy; check the weather when the night is within four days.

2042-10-12astronomy score per night — click a bar for that night2042-11-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-10-12 Sun	0	—	unknown	—	50.1° 12:30	9.69	1%	4.0°
2042-10-13 Mon	0	—	unknown	—	50.1° 12:25	9.74	0%	13.9°
2042-10-14 Tue	0	—	unknown	—	50.1° 12:20	9.78	1%	25.5°
2042-10-15 Wed	0	—	unknown	—	50.1° 12:15	9.83	3%	37.3°
2042-10-16 Thu	0	—	unknown	—	50.1° 12:10	9.87	7%	49.1°
2042-10-17 Fri	0	—	unknown	—	50.1° 12:10	9.91	13%	61.0°
2042-10-18 Sat	0	—	unknown	—	50.1° 12:00	9.95	20%	73.1°
2042-10-19 Sun	0	—	unknown	—	50.1° 12:00	10.0	28%	85.4°
2042-10-20 Mon	0	—	unknown	—	50.1° 11:55	10.04	38%	97.8°
2042-10-21 Tue	0	—	unknown	—	50.1° 11:50	10.08	48%	110.7°
2042-10-22 Wed	0	—	unknown	—	50.1° 11:45	10.12	58%	123.8°
2042-10-23 Thu	0	—	unknown	—	50.1° 11:40	10.16	69%	137.4°
2042-10-24 Fri	0	—	unknown	—	50.1° 11:35	10.2	79%	151.4°
2042-10-25 Sat	0	—	unknown	—	50.1° 10:35	10.24	88%	165.7°
2042-10-26 Sun	0	—	unknown	—	50.1° 10:30	10.28	94%	176.2°
2042-10-27 Mon	0	—	unknown	—	50.1° 10:25	10.32	99%	163.4°
2042-10-28 Tue	0	—	unknown	—	50.1° 10:20	10.36	100%	148.3°
2042-10-29 Wed	0	—	unknown	—	50.1° 10:15	10.4	98%	133.2°
2042-10-30 Thu	0	—	unknown	—	50.1° 10:15	10.43	93%	118.3°
2042-10-31 Fri	0	—	unknown	—	50.1° 10:10	10.47	86%	103.7°
2042-11-01 Sat	0	—	unknown	—	50.1° 10:05	10.51	78%	89.6°
2042-11-02 Sun	0	—	unknown	—	50.1° 10:00	10.54	68%	75.9°
2042-11-03 Mon	0	—	unknown	—	50.1° 10:00	10.58	58%	62.8°
2042-11-04 Tue	0	—	unknown	—	50.1° 09:55	10.61	47%	50.0°
2042-11-05 Wed	1	—	unknown	—	50.1° 09:50	10.65	38%	37.7°
2042-11-06 Thu	1	—	unknown	—	50.1° 09:45	10.68	28%	25.6°
2042-11-07 Fri	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:40	10.71	20%	13.8°
2042-11-08 Sat	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:40	10.75	13%	3.9°
2042-11-09 Sun	3	—	unknown	05:50–06:05 (marginal, 0.25 h)	50.1° 09:35	10.78	8%	11.0°
2042-11-10 Mon	4	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.1° 09:30	10.81	3%	22.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-10-12&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.