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: 11-08 (3), 11-07 (2), 11-04 (1), 11-05 (1), 11-06 (1) — by astronomy; check the weather when the night is within four days.

2026-10-10astronomy score per night — click a bar for that night2026-11-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-10-10 Sat	0	0	0	—	50.2° 12:35	9.6	0%	17.3°
2026-10-11 Sun	0	0	0	—	50.2° 12:30	9.64	2%	29.2°
2026-10-12 Mon	0	0	0	—	50.2° 12:30	9.69	6%	41.4°
2026-10-13 Tue	0	0	0	—	50.2° 12:25	9.73	11%	53.5°
2026-10-14 Wed	0	—	unknown	—	50.2° 12:20	9.78	17%	65.4°
2026-10-15 Thu	0	—	unknown	—	50.2° 12:15	9.82	25%	77.3°
2026-10-16 Fri	0	—	unknown	—	50.2° 12:10	9.86	34%	89.0°
2026-10-17 Sat	0	—	unknown	—	50.2° 12:10	9.91	43%	100.7°
2026-10-18 Sun	0	—	unknown	—	50.2° 12:00	9.95	52%	112.5°
2026-10-19 Mon	0	—	unknown	—	50.2° 12:00	9.99	62%	124.4°
2026-10-20 Tue	0	—	unknown	—	50.2° 11:50	10.03	71%	136.4°
2026-10-21 Wed	0	—	unknown	—	50.2° 11:50	10.08	80%	148.7°
2026-10-22 Thu	0	—	unknown	—	50.2° 11:45	10.12	87%	160.9°
2026-10-23 Fri	0	—	unknown	—	50.2° 11:40	10.16	94%	171.1°
2026-10-24 Sat	0	—	unknown	—	50.2° 10:35	10.2	98%	167.6°
2026-10-25 Sun	0	—	unknown	—	50.2° 10:35	10.24	100%	155.1°
2026-10-26 Mon	0	—	unknown	—	50.2° 10:30	10.28	99%	141.2°
2026-10-27 Tue	0	—	unknown	—	50.2° 10:25	10.31	96%	126.9°
2026-10-28 Wed	0	—	unknown	—	50.2° 10:20	10.35	90%	112.4°
2026-10-29 Thu	0	—	unknown	—	50.2° 10:15	10.39	81%	97.9°
2026-10-30 Fri	0	—	unknown	—	50.2° 10:15	10.43	71%	83.6°
2026-10-31 Sat	0	—	unknown	—	50.2° 10:10	10.47	60%	69.4°
2026-11-01 Sun	0	—	unknown	—	50.2° 10:05	10.5	49%	55.5°
2026-11-02 Mon	0	—	unknown	—	50.2° 10:00	10.54	38%	41.9°
2026-11-03 Tue	0	—	unknown	—	50.2° 09:55	10.57	28%	28.8°
2026-11-04 Wed	1	—	unknown	—	50.2° 09:55	10.61	19%	16.4°
2026-11-05 Thu	1	—	unknown	—	50.2° 09:50	10.64	12%	8.0°
2026-11-06 Fri	1	—	unknown	—	50.2° 09:45	10.68	6%	14.0°
2026-11-07 Sat	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.2° 09:40	10.71	2%	25.5°
2026-11-08 Sun	3	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.2° 09:40	10.74	0%	37.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-10-10&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.