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: 12-23 (22), 12-24 (20), 12-25 (19), 12-26 (18), 12-27 (16) — by astronomy; check the weather when the night is within four days.

2046-12-23astronomy score per night — click a bar for that night2047-01-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-12-23 Sun	22	—	unknown	18:40–19:20 (good, 0.67 h)	71.2° 14:15	11.51	15%	87.7°
2046-12-24 Mon	20	—	unknown	18:40–19:15 (good, 0.58 h)	71.1° 14:10	11.5	8%	77.0°
2046-12-25 Tue	19	—	unknown	18:40–19:15 (good, 0.58 h)	71.1° 14:05	11.5	3%	66.7°
2046-12-26 Wed	18	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:05	11.5	0%	57.3°
2046-12-27 Thu	16	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:00	11.49	0%	49.4°
2046-12-28 Fri	15	—	unknown	18:40–19:00 (good, 0.33 h)	71.2° 13:55	11.48	3%	43.7°
2046-12-29 Sat	12	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 13:50	11.48	7%	40.9°
2046-12-30 Sun	10	—	unknown	18:40–18:50 (good, 0.17 h)	71.1° 13:45	11.47	13%	41.5°
2046-12-31 Mon	7	—	unknown	18:45–19:15 (marginal, 0.5 h)	71.1° 13:45	11.46	20%	45.0°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-12-23&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.