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: 05-23 (100), 05-24 (100), 05-25 (100), 05-26 (100), 05-27 (100) — by astronomy; check the weather when the night is within four days.

2044-05-21astronomy score per night — click a bar for that night2044-06-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-05-21 Sat	91	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.24	32%	57.1°
2044-05-22 Sun	97	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:20	5.19	23%	64.8°
2044-05-23 Mon	100	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:15	5.14	14%	73.8°
2044-05-24 Tue	100	—	unknown	00:10–03:55 (good, 3.75 h)	71.1° 05:10	5.1	7%	83.6°
2044-05-25 Wed	100	—	unknown	00:05–03:50 (good, 3.75 h)	71.1° 05:05	5.05	2%	93.9°
2044-05-26 Thu	100	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:05	5.01	0%	104.4°
2044-05-27 Fri	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 05:00	4.97	1%	114.3°
2044-05-28 Sat	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 04:55	4.92	5%	123.2°
2044-05-29 Sun	100	—	unknown	23:50–03:50 (good, 4.0 h)	71.1° 04:50	4.88	11%	130.1°
2044-05-30 Mon	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.85	20%	134.1°
2044-05-31 Tue	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.81	30%	134.7°
2044-06-01 Wed	100	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:40	4.77	41%	132.0°
2044-06-02 Thu	100	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:35	4.74	52%	126.7°
2044-06-03 Fri	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:30	4.7	62%	119.7°
2044-06-04 Sat	100	—	unknown	23:35–03:40 (good, 4.08 h)	71.1° 04:25	4.67	72%	111.8°
2044-06-05 Sun	100	—	unknown	23:40–03:40 (good, 4.0 h)	71.1° 04:25	4.64	80%	103.4°
2044-06-06 Mon	98	—	unknown	23:40–03:40 (good, 4.0 h)	71.1° 04:20	4.62	88%	94.8°
2044-06-07 Tue	75	—	unknown	23:55–03:40 (good, 3.75 h)	71.1° 04:15	4.59	93%	86.2°
2044-06-08 Wed	65	—	unknown	00:30–03:40 (good, 3.17 h)	71.1° 04:10	4.56	97%	77.8°
2044-06-09 Thu	56	—	unknown	01:05–03:40 (good, 2.58 h)	71.1° 04:10	4.54	99%	69.7°
2044-06-10 Fri	50	—	unknown	01:45–03:40 (good, 1.92 h)	71.1° 04:05	4.52	100%	62.2°
2044-06-11 Sat	45	—	unknown	03:20–03:40 (good, 0.33 h)	71.1° 04:00	4.5	98%	55.6°
2044-06-12 Sun	44	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:55	4.48	95%	50.2°
2044-06-13 Mon	67	—	unknown	23:10–23:40 (good, 0.5 h)	71.1° 03:50	4.47	90%	46.5°
2044-06-14 Tue	75	—	unknown	23:10–02:50 (good, 3.67 h)	71.1° 03:50	4.46	84%	45.0°
2044-06-15 Wed	85	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.45	76%	46.0°
2044-06-16 Thu	93	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.44	68%	49.4°
2044-06-17 Fri	96	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	58%	54.8°
2044-06-18 Sat	99	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:30	4.42	48%	61.9°
2044-06-19 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:30	4.42	37%	70.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-21&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.