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: 04-04 (49), 04-03 (48), 04-05 (48), 04-06 (48), 04-02 (47) — by astronomy; check the weather when the night is within four days.

2047-03-17astronomy score per night — click a bar for that night2047-04-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-03-17 Sun	21	—	unknown	04:00–05:00 (good, 1.0 h)	71.2° 08:40	8.88	58%	64.3°
2047-03-18 Mon	23	—	unknown	03:50–04:55 (good, 1.08 h)	71.1° 08:35	8.83	47%	55.4°
2047-03-19 Tue	26	—	unknown	03:45–04:55 (good, 1.17 h)	71.1° 08:35	8.78	37%	48.1°
2047-03-20 Wed	30	—	unknown	03:30–04:50 (good, 1.33 h)	71.1° 08:30	8.73	27%	43.0°
2047-03-21 Thu	35	—	unknown	03:25–04:50 (good, 1.42 h)	71.2° 08:25	8.67	18%	40.7°
2047-03-22 Fri	38	—	unknown	03:20–04:50 (good, 1.5 h)	71.1° 08:20	8.62	12%	41.6°
2047-03-23 Sat	38	—	unknown	03:15–04:45 (good, 1.5 h)	71.1° 08:15	8.57	6%	45.3°
2047-03-24 Sun	40	—	unknown	03:10–04:45 (good, 1.58 h)	71.1° 08:15	8.52	2%	51.1°
2047-03-25 Mon	41	—	unknown	03:10–04:45 (good, 1.58 h)	71.2° 08:10	8.46	0%	58.3°
2047-03-26 Tue	41	—	unknown	03:05–04:40 (good, 1.58 h)	71.2° 08:05	8.41	0%	66.4°
2047-03-27 Wed	42	—	unknown	03:00–04:40 (good, 1.67 h)	71.1° 08:00	8.36	2%	74.9°
2047-03-28 Thu	42	—	unknown	02:55–04:35 (good, 1.67 h)	71.1° 08:00	8.3	6%	83.8°
2047-03-29 Fri	43	—	unknown	02:50–04:35 (good, 1.75 h)	71.1° 07:55	8.25	10%	92.8°
2047-03-30 Sat	45	—	unknown	02:50–05:35 (good, 1.75 h)	71.2° 08:50	8.2	17%	101.7°
2047-03-31 Sun	45	—	unknown	03:45–05:30 (good, 1.75 h)	71.2° 08:45	8.14	25%	110.5°
2047-04-01 Mon	46	—	unknown	03:40–05:30 (good, 1.83 h)	71.1° 08:40	8.09	33%	119.0°
2047-04-02 Tue	47	—	unknown	03:35–05:30 (good, 1.92 h)	71.1° 08:40	8.03	43%	126.8°
2047-04-03 Wed	48	—	unknown	03:35–05:25 (good, 1.83 h)	71.1° 08:35	7.98	53%	133.4°
2047-04-04 Thu	49	—	unknown	03:35–05:25 (good, 1.83 h)	71.2° 08:30	7.92	63%	138.0°
2047-04-05 Fri	48	—	unknown	03:30–05:20 (good, 1.83 h)	71.1° 08:25	7.87	74%	139.5°
2047-04-06 Sat	48	—	unknown	03:30–05:20 (good, 1.83 h)	71.1° 08:20	7.81	83%	137.2°
2047-04-07 Sun	45	—	unknown	03:25–05:20 (good, 1.92 h)	71.1° 08:20	7.75	91%	131.3°
2047-04-08 Mon	43	—	unknown	03:25–05:15 (good, 1.83 h)	71.2° 08:15	7.7	96%	122.7°
2047-04-09 Tue	40	—	unknown	03:25–05:15 (good, 1.83 h)	71.2° 08:10	7.64	99%	112.5°
2047-04-10 Wed	35	—	unknown	03:25–05:10 (good, 1.75 h)	71.1° 08:05	7.58	99%	101.2°
2047-04-11 Thu	31	—	unknown	03:35–05:10 (good, 1.58 h)	71.1° 08:00	7.53	96%	89.7°
2047-04-12 Fri	29	—	unknown	04:00–05:10 (good, 1.17 h)	71.1° 08:00	7.47	91%	78.3°
2047-04-13 Sat	28	—	unknown	04:05–05:05 (good, 1.0 h)	71.2° 07:55	7.41	83%	67.6°
2047-04-14 Sun	29	—	unknown	03:45–05:05 (good, 1.33 h)	71.2° 07:50	7.36	73%	57.9°
2047-04-15 Mon	31	—	unknown	03:10–05:00 (good, 1.83 h)	71.1° 07:45	7.3	63%	49.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-03-17&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.