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: 03-07 (27), 03-08 (27), 03-09 (27), 03-06 (26), 03-05 (25) — by astronomy; check the weather when the night is within four days.

2044-02-15astronomy score per night — click a bar for that night2044-03-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-02-15 Mon	7	—	unknown	05:10–05:45 (marginal, 0.58 h)	71.1° 10:40	10.26	92%	117.9°
2044-02-16 Tue	7	—	unknown	05:05–05:45 (marginal, 0.67 h)	71.1° 10:35	10.22	85%	109.7°
2044-02-17 Wed	8	—	unknown	05:05–06:15 (marginal, 1.17 h)	71.1° 10:30	10.18	77%	101.2°
2044-02-18 Thu	8	—	unknown	05:00–05:40 (marginal, 0.67 h)	71.1° 10:30	10.14	68%	92.6°
2044-02-19 Fri	8	—	unknown	04:55–06:10 (marginal, 1.25 h)	71.1° 10:25	10.1	59%	84.1°
2044-02-20 Sat	10	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:20	10.06	49%	75.9°
2044-02-21 Sun	11	—	unknown	05:25–05:35 (good, 0.17 h)	71.1° 10:15	10.01	40%	68.1°
2044-02-22 Mon	12	—	unknown	05:20–05:35 (good, 0.25 h)	71.1° 10:10	9.97	31%	60.8°
2044-02-23 Tue	14	—	unknown	05:15–05:35 (good, 0.33 h)	71.1° 10:10	9.93	22%	54.5°
2044-02-24 Wed	17	—	unknown	05:05–05:35 (good, 0.5 h)	71.1° 10:05	9.89	15%	49.5°
2044-02-25 Thu	18	—	unknown	05:00–05:30 (good, 0.5 h)	71.1° 10:00	9.84	9%	46.3°
2044-02-26 Fri	18	—	unknown	04:55–05:30 (good, 0.58 h)	71.1° 09:55	9.8	4%	45.6°
2044-02-27 Sat	20	—	unknown	04:50–05:30 (good, 0.67 h)	71.1° 09:50	9.75	1%	47.5°
2044-02-28 Sun	20	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:50	9.71	0%	52.0°
2044-02-29 Mon	22	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:45	9.66	1%	58.5°
2044-03-01 Tue	22	—	unknown	04:40–05:25 (good, 0.75 h)	71.1° 09:40	9.62	5%	66.5°
2044-03-02 Wed	22	—	unknown	04:35–05:20 (good, 0.75 h)	71.1° 09:35	9.57	11%	75.5°
2044-03-03 Thu	24	—	unknown	04:30–05:20 (good, 0.83 h)	71.1° 09:35	9.53	19%	85.0°
2044-03-04 Fri	24	—	unknown	04:30–05:20 (good, 0.83 h)	71.1° 09:30	9.48	28%	94.8°
2044-03-05 Sat	25	—	unknown	04:25–05:15 (good, 0.83 h)	71.1° 09:25	9.43	39%	104.5°
2044-03-06 Sun	26	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:20	9.38	51%	113.7°
2044-03-07 Mon	27	—	unknown	04:15–05:15 (good, 1.0 h)	71.1° 09:15	9.34	62%	122.0°
2044-03-08 Tue	27	—	unknown	04:15–05:10 (good, 0.92 h)	71.1° 09:15	9.29	73%	128.8°
2044-03-09 Wed	27	—	unknown	04:15–05:10 (good, 0.92 h)	71.1° 09:10	9.24	82%	133.2°
2044-03-10 Thu	25	—	unknown	04:10–05:10 (good, 1.0 h)	71.1° 09:05	9.19	90%	134.5°
2044-03-11 Fri	24	—	unknown	04:10–05:05 (good, 0.92 h)	71.1° 09:00	9.14	96%	132.5°
2044-03-12 Sat	25	—	unknown	04:05–05:05 (good, 1.0 h)	71.1° 08:55	9.09	99%	127.7°
2044-03-13 Sun	25	—	unknown	04:05–05:05 (good, 1.0 h)	71.1° 08:55	9.04	100%	120.9°
2044-03-14 Mon	23	—	unknown	04:05–05:00 (good, 0.92 h)	71.1° 08:50	8.99	99%	113.0°
2044-03-15 Tue	22	—	unknown	04:05–05:00 (good, 0.92 h)	71.1° 08:45	8.94	95%	104.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-02-15&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.