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: 07-21 (1) — by astronomy; check the weather when the night is within four days.

2046-07-21astronomy score per night — click a bar for that night2046-08-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-07-21 Sat	1	—	unknown	—	50.1° 17:55	5.28	86%	156.0°
2046-07-22 Sun	0	—	unknown	—	50.1° 17:50	5.33	79%	166.1°
2046-07-23 Mon	0	—	unknown	—	50.1° 17:45	5.38	70%	170.5°
2046-07-24 Tue	0	—	unknown	—	50.1° 17:45	5.43	62%	163.7°
2046-07-25 Wed	0	—	unknown	—	50.1° 17:40	5.48	52%	153.1°
2046-07-26 Thu	0	—	unknown	—	50.1° 17:35	5.53	42%	141.5°
2046-07-27 Fri	0	—	unknown	—	50.1° 17:30	5.59	33%	129.5°
2046-07-28 Sat	0	—	unknown	—	50.1° 17:25	5.64	23%	117.0°
2046-07-29 Sun	0	—	unknown	—	50.1° 17:25	5.69	15%	104.1°
2046-07-30 Mon	0	—	unknown	—	50.1° 17:20	5.75	8%	90.8°
2046-07-31 Tue	0	—	unknown	—	50.1° 17:15	5.8	3%	77.0°
2046-08-01 Wed	0	—	unknown	—	50.1° 17:10	5.86	0%	62.9°
2046-08-02 Thu	0	—	unknown	—	50.1° 17:05	5.91	0%	48.5°
2046-08-03 Fri	0	—	unknown	—	50.1° 17:05	5.97	3%	34.2°
2046-08-04 Sat	0	—	unknown	—	50.1° 17:00	6.02	9%	20.4°
2046-08-05 Sun	0	—	unknown	—	50.1° 16:55	6.08	17%	10.0°
2046-08-06 Mon	0	—	unknown	—	50.1° 16:50	6.14	27%	14.5°
2046-08-07 Tue	0	—	unknown	—	50.1° 16:50	6.19	37%	27.0°
2046-08-08 Wed	0	—	unknown	—	50.1° 16:45	6.25	49%	40.4°
2046-08-09 Thu	0	—	unknown	—	50.1° 16:40	6.31	60%	53.7°
2046-08-10 Fri	0	—	unknown	—	50.1° 16:35	6.36	70%	66.9°
2046-08-11 Sat	0	—	unknown	—	50.1° 16:30	6.42	79%	79.8°
2046-08-12 Sun	0	—	unknown	—	50.1° 16:30	6.48	87%	92.6°
2046-08-13 Mon	0	—	unknown	—	50.1° 16:25	6.54	93%	105.1°
2046-08-14 Tue	0	—	unknown	—	50.1° 16:20	6.59	97%	117.4°
2046-08-15 Wed	0	—	unknown	—	50.1° 16:15	6.65	100%	129.5°
2046-08-16 Thu	0	—	unknown	—	50.1° 16:10	6.71	100%	141.3°
2046-08-17 Fri	0	—	unknown	—	50.1° 16:10	6.77	98%	152.8°
2046-08-18 Sat	0	—	unknown	—	50.1° 16:05	6.82	95%	163.4°
2046-08-19 Sun	0	—	unknown	—	50.1° 16:00	6.88	90%	170.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-07-21&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.