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: 06-02 (100), 06-03 (100), 06-04 (100), 06-05 (100), 06-06 (100) — by astronomy; check the weather when the night is within four days.

2043-05-25astronomy score per night — click a bar for that night2043-06-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-05-25 Mon	42	—	unknown	02:40–03:55 (good, 1.25 h)	71.1° 05:10	5.09	96%	61.0°
2043-05-26 Tue	41	—	unknown	02:40–03:50 (good, 1.17 h)	71.1° 05:05	5.04	92%	54.8°
2043-05-27 Wed	55	—	unknown	01:50–03:50 (good, 2.0 h)	71.1° 05:00	5.0	86%	49.9°
2043-05-28 Thu	67	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 05:00	4.96	78%	47.0°
2043-05-29 Fri	78	—	unknown	23:50–03:50 (good, 4.0 h)	71.1° 04:55	4.92	69%	46.6°
2043-05-30 Sat	87	—	unknown	23:50–03:45 (good, 3.92 h)	71.1° 04:50	4.88	59%	48.8°
2043-05-31 Sun	96	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.84	49%	53.5°
2043-06-01 Mon	99	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:40	4.8	38%	60.2°
2043-06-02 Tue	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:40	4.76	27%	68.6°
2043-06-03 Wed	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:35	4.73	17%	78.0°
2043-06-04 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:30	4.7	9%	88.1°
2043-06-05 Fri	100	—	unknown	23:25–03:40 (good, 4.25 h)	71.1° 04:25	4.67	4%	98.5°
2043-06-06 Sat	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:20	4.64	1%	108.6°
2043-06-07 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:20	4.61	0%	117.8°
2043-06-08 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.58	4%	125.6°
2043-06-09 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:10	4.56	9%	131.0°
2043-06-10 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	71.1° 04:05	4.54	16%	133.5°
2043-06-11 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:05	4.52	25%	132.9°
2043-06-12 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.5	35%	129.6°
2043-06-13 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:55	4.48	45%	124.2°
2043-06-14 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:50	4.47	55%	117.6°
2043-06-15 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.45	64%	110.2°
2043-06-16 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.44	73%	102.3°
2043-06-17 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.43	81%	94.2°
2043-06-18 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	88%	86.1°
2043-06-19 Fri	76	—	unknown	23:40–03:40 (good, 4.0 h)	71.1° 03:30	4.42	93%	78.0°
2043-06-20 Sat	65	—	unknown	00:20–03:40 (good, 3.33 h)	71.1° 03:25	4.42	97%	70.1°
2043-06-21 Sun	56	—	unknown	01:00–03:40 (good, 2.67 h)	71.1° 03:25	4.42	99%	62.8°
2043-06-22 Mon	49	—	unknown	02:40–03:40 (good, 1.0 h)	71.1° 03:20	4.42	100%	56.2°
2043-06-23 Tue	45	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:15	4.43	98%	50.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-05-25&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.