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 HD 189733: 01-01 (6), 01-02 (4), 01-03 (3), 01-04 (3), 01-05 (2) — by astronomy; check the weather when the night is within four days.

2047-01-01astronomy score per night — click a bar for that night2047-01-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-01-01 Tue	6	—	unknown	18:45–19:15 (marginal, 0.5 h)	71.2° 13:40	11.45	29%	50.7°
2047-01-02 Wed	4	—	unknown	18:45–19:10 (marginal, 0.42 h)	71.1° 13:35	11.44	38%	57.7°
2047-01-03 Thu	3	—	unknown	18:45–19:05 (marginal, 0.33 h)	71.1° 13:30	11.43	47%	65.7°
2047-01-04 Fri	3	—	unknown	18:45–19:00 (marginal, 0.25 h)	71.1° 13:30	11.42	57%	74.2°
2047-01-05 Sat	2	—	unknown	18:45–18:55 (marginal, 0.17 h)	71.1° 13:25	11.4	66%	83.0°
2047-01-06 Sun	2	—	unknown	18:50–18:55 (marginal, 0.08 h)	71.2° 13:20	11.39	75%	92.1°
2047-01-07 Mon	1	—	unknown	—	71.1° 13:15	11.37	83%	101.3°
2047-01-08 Tue	1	—	unknown	—	71.1° 13:10	11.36	90%	110.5°
2047-01-09 Wed	1	—	unknown	—	71.1° 13:10	11.34	95%	119.3°
2047-01-10 Thu	1	—	unknown	—	71.1° 13:05	11.33	98%	127.5°
2047-01-11 Fri	1	—	unknown	—	71.2° 13:00	11.31	100%	134.2°
2047-01-12 Sat	0	—	unknown	—	71.1° 12:55	11.29	99%	138.4°
2047-01-13 Sun	0	—	unknown	—	71.1° 12:50	11.27	96%	139.0°
2047-01-14 Mon	0	—	unknown	—	71.1° 12:50	11.25	90%	135.9°
2047-01-15 Tue	0	—	unknown	—	71.2° 12:45	11.23	82%	129.5°
2047-01-16 Wed	0	—	unknown	—	71.2° 12:40	11.21	72%	121.0°
2047-01-17 Thu	0	—	unknown	—	71.1° 12:35	11.18	61%	111.3°
2047-01-18 Fri	0	—	unknown	—	71.1° 12:35	11.16	50%	101.0°
2047-01-19 Sat	0	—	unknown	—	71.1° 12:30	11.13	39%	90.4°
2047-01-20 Sun	0	—	unknown	—	71.2° 12:25	11.11	28%	79.8°
2047-01-21 Mon	0	—	unknown	—	71.1° 12:20	11.08	19%	69.6°
2047-01-22 Tue	0	—	unknown	—	71.1° 12:15	11.06	11%	60.1°
2047-01-23 Wed	0	—	unknown	—	71.1° 12:15	11.03	5%	51.8°
2047-01-24 Thu	0	—	unknown	—	71.1° 12:10	11.0	1%	45.4°
2047-01-25 Fri	0	—	unknown	—	71.2° 12:05	10.98	0%	41.5°
2047-01-26 Sat	0	—	unknown	—	71.1° 12:00	10.95	1%	40.9°
2047-01-27 Sun	1	—	unknown	—	71.1° 11:55	10.92	4%	43.4°
2047-01-28 Mon	1	—	unknown	—	71.2° 11:50	10.89	8%	48.5°
2047-01-29 Tue	1	—	unknown	—	71.2° 11:45	10.86	14%	55.2°
2047-01-30 Wed	1	—	unknown	—	71.1° 11:40	10.82	22%	62.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-01-01&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.