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: 11-11 (6), 11-10 (5), 11-09 (4), 11-08 (3), 11-07 (2) — by astronomy; check the weather when the night is within four days.

2040-10-13astronomy score per night — click a bar for that night2040-11-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-10-13 Sat	0	—	unknown	—	50.1° 12:20	9.76	56%	113.0°
2040-10-14 Sun	0	—	unknown	—	50.1° 12:20	9.8	68%	127.2°
2040-10-15 Mon	0	—	unknown	—	50.1° 12:15	9.85	78%	141.4°
2040-10-16 Tue	0	—	unknown	—	50.1° 12:10	9.89	87%	155.7°
2040-10-17 Wed	0	—	unknown	—	50.1° 12:05	9.93	93%	169.8°
2040-10-18 Thu	0	—	unknown	—	50.1° 12:00	9.98	98%	176.0°
2040-10-19 Fri	0	—	unknown	—	50.1° 11:55	10.02	100%	162.2°
2040-10-20 Sat	0	—	unknown	—	50.1° 11:50	10.06	99%	148.7°
2040-10-21 Sun	0	—	unknown	—	50.1° 11:45	10.1	97%	135.4°
2040-10-22 Mon	0	—	unknown	—	50.1° 11:45	10.14	92%	122.4°
2040-10-23 Tue	0	—	unknown	—	50.1° 11:40	10.18	86%	109.8°
2040-10-24 Wed	0	—	unknown	—	50.1° 11:35	10.22	78%	97.5°
2040-10-25 Thu	0	—	unknown	—	50.1° 11:30	10.26	69%	85.4°
2040-10-26 Fri	0	—	unknown	—	50.1° 11:25	10.3	60%	73.4°
2040-10-27 Sat	0	—	unknown	—	50.1° 10:25	10.34	51%	61.6°
2040-10-28 Sun	0	—	unknown	—	50.1° 10:20	10.38	42%	49.8°
2040-10-29 Mon	0	—	unknown	—	50.1° 10:15	10.41	32%	37.9°
2040-10-30 Tue	0	—	unknown	—	50.1° 10:10	10.45	24%	25.8°
2040-10-31 Wed	0	—	unknown	—	50.1° 10:05	10.49	16%	13.5°
2040-11-01 Thu	0	—	unknown	—	50.1° 10:05	10.52	9%	1.1°
2040-11-02 Fri	0	—	unknown	—	50.1° 10:00	10.56	4%	12.2°
2040-11-03 Sat	1	—	unknown	—	50.1° 09:55	10.59	1%	25.4°
2040-11-04 Sun	1	—	unknown	—	50.1° 09:50	10.63	0%	39.0°
2040-11-05 Mon	1	—	unknown	—	50.1° 09:50	10.66	2%	52.9°
2040-11-06 Tue	1	—	unknown	05:55–06:00 (marginal, 0.08 h)	50.1° 09:45	10.7	6%	67.0°
2040-11-07 Wed	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:40	10.73	12%	81.2°
2040-11-08 Thu	3	—	unknown	05:50–06:05 (marginal, 0.25 h)	50.1° 09:35	10.76	21%	95.5°
2040-11-09 Fri	4	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.1° 09:30	10.8	31%	109.8°
2040-11-10 Sat	5	—	unknown	05:15–05:35 (marginal, 0.33 h)	50.1° 09:30	10.83	42%	124.0°
2040-11-11 Sun	6	—	unknown	05:10–06:05 (marginal, 0.92 h)	50.1° 09:25	10.86	53%	138.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-10-13&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.