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: 02-10 (6), 02-08 (5), 02-09 (5), 02-07 (4), 02-04 (3) — by astronomy; check the weather when the night is within four days.

2046-01-12astronomy score per night — click a bar for that night2046-02-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-01-12 Fri	0	—	unknown	—	71.1° 12:55	11.28	27%	56.9°
2046-01-13 Sat	0	—	unknown	—	71.1° 12:50	11.26	36%	64.4°
2046-01-14 Sun	0	—	unknown	—	71.1° 12:45	11.24	45%	72.7°
2046-01-15 Mon	0	—	unknown	—	71.1° 12:45	11.22	55%	81.5°
2046-01-16 Tue	0	—	unknown	—	71.1° 12:40	11.2	65%	90.7°
2046-01-17 Wed	0	—	unknown	—	71.1° 12:35	11.18	75%	100.2°
2046-01-18 Thu	0	—	unknown	—	71.1° 12:30	11.15	83%	109.8°
2046-01-19 Fri	0	—	unknown	—	71.1° 12:30	11.13	91%	119.1°
2046-01-20 Sat	0	—	unknown	—	71.1° 12:25	11.1	96%	127.5°
2046-01-21 Sun	0	—	unknown	—	71.1° 12:20	11.08	100%	134.0°
2046-01-22 Mon	0	—	unknown	—	71.1° 12:15	11.05	100%	137.4°
2046-01-23 Tue	0	—	unknown	—	71.1° 12:10	11.02	97%	136.6°
2046-01-24 Wed	0	—	unknown	—	71.1° 12:10	11.0	92%	131.9°
2046-01-25 Thu	0	—	unknown	—	71.1° 12:00	10.97	84%	124.4°
2046-01-26 Fri	0	—	unknown	—	71.1° 12:00	10.94	74%	115.3°
2046-01-27 Sat	0	—	unknown	—	71.1° 11:50	10.91	64%	105.5°
2046-01-28 Sun	1	—	unknown	—	71.1° 11:50	10.88	53%	95.4°
2046-01-29 Mon	1	—	unknown	—	71.1° 11:45	10.85	42%	85.5°
2046-01-30 Tue	1	—	unknown	—	71.1° 11:40	10.82	32%	75.9°
2046-01-31 Wed	1	—	unknown	—	71.1° 11:35	10.79	22%	66.9°
2046-02-01 Thu	1	—	unknown	—	71.1° 11:35	10.75	15%	58.7°
2046-02-02 Fri	1	—	unknown	—	71.1° 11:30	10.72	8%	51.7°
2046-02-03 Sat	2	—	unknown	05:55–06:00 (marginal, 0.08 h)	71.1° 11:25	10.69	4%	46.3°
2046-02-04 Sun	3	—	unknown	06:20–06:30 (marginal, 0.17 h)	71.1° 11:20	10.65	1%	43.1°
2046-02-05 Mon	3	—	unknown	06:15–06:30 (marginal, 0.25 h)	71.1° 11:15	10.62	0%	42.5°
2046-02-06 Tue	3	—	unknown	06:10–06:25 (marginal, 0.25 h)	71.1° 11:15	10.58	1%	44.6°
2046-02-07 Wed	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.54	4%	48.9°
2046-02-08 Thu	5	—	unknown	05:35–05:55 (marginal, 0.33 h)	71.1° 11:05	10.51	8%	55.0°
2046-02-09 Fri	5	—	unknown	06:00–06:25 (marginal, 0.42 h)	71.1° 11:00	10.47	14%	62.2°
2046-02-10 Sat	6	—	unknown	05:55–06:25 (marginal, 0.5 h)	71.1° 10:55	10.43	21%	70.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-01-12&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.