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: 11-16 (13), 11-15 (11), 11-14 (9), 11-13 (8), 11-12 (6) — by astronomy; check the weather when the night is within four days.

2031-10-18astronomy score per night — click a bar for that night2031-11-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-10-18 Sat	0	—	unknown	—	50.2° 12:05	9.94	8%	52.0°
2031-10-19 Sun	0	—	unknown	—	50.2° 12:00	9.98	15%	65.8°
2031-10-20 Mon	0	—	unknown	—	50.2° 11:55	10.02	24%	79.7°
2031-10-21 Tue	0	—	unknown	—	50.2° 11:50	10.07	34%	93.7°
2031-10-22 Wed	0	—	unknown	—	50.2° 11:45	10.11	46%	107.7°
2031-10-23 Thu	0	—	unknown	—	50.2° 11:40	10.15	57%	121.6°
2031-10-24 Fri	0	—	unknown	—	50.2° 11:40	10.19	68%	135.5°
2031-10-25 Sat	0	—	unknown	—	50.2° 10:35	10.23	78%	149.1°
2031-10-26 Sun	0	—	unknown	—	50.2° 10:30	10.27	87%	162.1°
2031-10-27 Mon	0	—	unknown	—	50.2° 10:25	10.31	93%	171.4°
2031-10-28 Tue	0	—	unknown	—	50.2° 10:20	10.34	98%	165.7°
2031-10-29 Wed	0	—	unknown	—	50.2° 10:20	10.38	100%	153.7°
2031-10-30 Thu	0	—	unknown	—	50.2° 10:15	10.42	100%	141.0°
2031-10-31 Fri	0	—	unknown	—	50.2° 10:10	10.46	97%	128.4°
2031-11-01 Sat	0	—	unknown	—	50.2° 10:05	10.49	93%	115.9°
2031-11-02 Sun	0	—	unknown	—	50.2° 10:00	10.53	87%	103.7°
2031-11-03 Mon	0	—	unknown	—	50.2° 10:00	10.57	80%	91.7°
2031-11-04 Tue	0	—	unknown	—	50.2° 09:55	10.6	72%	79.9°
2031-11-05 Wed	1	—	unknown	—	50.2° 09:50	10.64	63%	68.1°
2031-11-06 Thu	1	—	unknown	—	50.2° 09:45	10.67	54%	56.5°
2031-11-07 Fri	1	—	unknown	—	50.2° 09:45	10.7	44%	44.8°
2031-11-08 Sat	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.2° 09:40	10.74	35%	33.1°
2031-11-09 Sun	2	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.2° 09:35	10.77	26%	21.5°
2031-11-10 Mon	4	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.2° 09:30	10.8	17%	11.1°
2031-11-11 Tue	5	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.2° 09:25	10.83	10%	10.1°
2031-11-12 Wed	6	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.2° 09:25	10.86	5%	20.6°
2031-11-13 Thu	8	—	unknown	05:30–05:35 (good, 0.08 h)	50.2° 09:20	10.89	1%	33.5°
2031-11-14 Fri	9	—	unknown	05:30–05:35 (good, 0.08 h)	50.2° 09:15	10.92	0%	47.1°
2031-11-15 Sat	11	—	unknown	05:25–05:35 (good, 0.17 h)	50.2° 09:10	10.95	1%	61.2°
2031-11-16 Sun	13	—	unknown	05:20–05:40 (good, 0.33 h)	50.2° 09:05	10.98	6%	75.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-10-18&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.