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), 11-08 (3), 11-09 (3), 11-07 (2), 11-03 (1) — by astronomy; check the weather when the night is within four days.

2030-10-12astronomy score per night — click a bar for that night2030-11-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-10-12 Sat	0	—	unknown	—	50.2° 12:30	9.69	98%	148.6°
2030-10-13 Sun	0	—	unknown	—	50.2° 12:25	9.74	94%	136.9°
2030-10-14 Mon	0	—	unknown	—	50.2° 12:20	9.78	89%	125.1°
2030-10-15 Tue	0	—	unknown	—	50.2° 12:15	9.82	82%	113.4°
2030-10-16 Wed	0	—	unknown	—	50.2° 12:10	9.87	75%	101.8°
2030-10-17 Thu	0	—	unknown	—	50.2° 12:10	9.91	66%	90.1°
2030-10-18 Fri	0	—	unknown	—	50.2° 12:00	9.95	57%	78.4°
2030-10-19 Sat	0	—	unknown	—	50.2° 12:00	9.99	47%	66.5°
2030-10-20 Sun	0	—	unknown	—	50.2° 11:50	10.03	37%	54.4°
2030-10-21 Mon	0	—	unknown	—	50.2° 11:50	10.08	28%	42.0°
2030-10-22 Tue	0	—	unknown	—	50.2° 11:45	10.12	19%	29.5°
2030-10-23 Wed	0	—	unknown	—	50.2° 11:40	10.16	11%	17.3°
2030-10-24 Thu	0	—	unknown	—	50.2° 11:35	10.2	5%	9.4°
2030-10-25 Fri	0	—	unknown	—	50.2° 11:35	10.24	1%	16.5°
2030-10-26 Sat	0	—	unknown	—	50.2° 10:30	10.28	0%	29.6°
2030-10-27 Sun	0	—	unknown	—	50.2° 10:25	10.32	2%	43.9°
2030-10-28 Mon	0	—	unknown	—	50.2° 10:20	10.35	6%	58.5°
2030-10-29 Tue	0	—	unknown	—	50.2° 10:15	10.39	13%	73.2°
2030-10-30 Wed	0	—	unknown	—	50.2° 10:15	10.43	22%	87.6°
2030-10-31 Thu	0	—	unknown	—	50.2° 10:10	10.47	32%	101.8°
2030-11-01 Fri	0	—	unknown	—	50.2° 10:05	10.5	44%	115.7°
2030-11-02 Sat	0	—	unknown	—	50.2° 10:00	10.54	55%	129.2°
2030-11-03 Sun	1	—	unknown	—	50.2° 09:55	10.57	65%	142.2°
2030-11-04 Mon	1	—	unknown	—	50.2° 09:55	10.61	75%	154.6°
2030-11-05 Tue	1	—	unknown	—	50.2° 09:50	10.64	83%	165.7°
2030-11-06 Wed	1	—	unknown	—	50.2° 09:45	10.68	90%	170.4°
2030-11-07 Thu	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.2° 09:40	10.71	95%	162.9°
2030-11-08 Fri	3	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.2° 09:40	10.74	98%	151.9°
2030-11-09 Sat	3	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.2° 09:35	10.78	100%	140.3°
2030-11-10 Sun	4	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.2° 09:30	10.81	99%	128.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-10-12&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.