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: 01-04 (5), 01-05 (4), 01-06 (3), 01-07 (2), 01-08 (2) — by astronomy; check the weather when the night is within four days.

2048-01-04astronomy score per night — click a bar for that night2048-02-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-01-04 Sat	5	—	unknown	18:10–18:35 (marginal, 0.42 h)	71.2° 13:30	11.42	87%	138.7°
2048-01-05 Sun	4	—	unknown	18:45–19:00 (marginal, 0.25 h)	71.2° 13:25	11.41	79%	133.6°
2048-01-06 Mon	3	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.2° 13:20	11.39	70%	126.2°
2048-01-07 Tue	2	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.1° 13:15	11.38	59%	117.2°
2048-01-08 Wed	2	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:15	11.36	48%	107.1°
2048-01-09 Thu	1	—	unknown	—	71.2° 13:10	11.35	37%	96.4°
2048-01-10 Fri	1	—	unknown	—	71.2° 13:05	11.33	26%	85.3°
2048-01-11 Sat	1	—	unknown	—	71.2° 13:00	11.31	17%	74.2°
2048-01-12 Sun	1	—	unknown	—	71.1° 12:55	11.29	9%	63.4°
2048-01-13 Mon	0	—	unknown	—	71.2° 12:55	11.27	3%	53.6°
2048-01-14 Tue	0	—	unknown	—	71.2° 12:50	11.25	0%	45.6°
2048-01-15 Wed	0	—	unknown	—	71.2° 12:45	11.23	0%	40.5°
2048-01-16 Thu	0	—	unknown	—	71.2° 12:40	11.21	3%	39.3°
2048-01-17 Fri	0	—	unknown	—	71.1° 12:40	11.19	8%	42.2°
2048-01-18 Sat	0	—	unknown	—	71.2° 12:35	11.16	14%	48.1°
2048-01-19 Sun	0	—	unknown	—	71.2° 12:30	11.14	22%	55.7°
2048-01-20 Mon	0	—	unknown	—	71.2° 12:25	11.12	31%	64.3°
2048-01-21 Tue	0	—	unknown	—	71.1° 12:20	11.09	41%	73.3°
2048-01-22 Wed	0	—	unknown	—	71.1° 12:20	11.06	50%	82.5°
2048-01-23 Thu	0	—	unknown	—	71.2° 12:15	11.04	60%	91.7°
2048-01-24 Fri	0	—	unknown	—	71.2° 12:10	11.01	69%	100.8°
2048-01-25 Sat	0	—	unknown	—	71.2° 12:05	10.98	77%	109.7°
2048-01-26 Sun	0	—	unknown	—	71.2° 12:00	10.95	84%	118.3°
2048-01-27 Mon	0	—	unknown	—	71.2° 11:55	10.92	91%	126.3°
2048-01-28 Tue	1	—	unknown	—	71.2° 11:50	10.89	96%	133.2°
2048-01-29 Wed	1	—	unknown	—	71.2° 11:45	10.86	99%	138.3°
2048-01-30 Thu	1	—	unknown	—	71.1° 11:45	10.83	100%	140.7°
2048-01-31 Fri	1	—	unknown	—	71.2° 11:40	10.8	99%	139.6°
2048-02-01 Sat	1	—	unknown	—	71.2° 11:35	10.77	96%	135.1°
2048-02-02 Sun	1	—	unknown	—	71.2° 11:30	10.74	90%	128.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-01-04&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.