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.

2043-05-13astronomy score per night — click a bar for that night2043-06-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-05-13 Wed	88	—	unknown	00:55–04:10 (good, 3.25 h)	71.1° 05:55	5.69	30%	132.2°
2043-05-14 Thu	89	—	unknown	00:55–04:10 (good, 3.25 h)	71.1° 05:55	5.64	40%	133.5°
2043-05-15 Fri	88	—	unknown	00:50–04:05 (good, 3.25 h)	71.1° 05:50	5.58	50%	131.9°
2043-05-16 Sat	88	—	unknown	00:50–04:05 (good, 3.25 h)	71.1° 05:45	5.53	61%	127.9°
2043-05-17 Sun	89	—	unknown	00:45–04:05 (good, 3.33 h)	71.1° 05:40	5.48	70%	122.3°
2043-05-18 Mon	87	—	unknown	00:45–04:05 (good, 3.33 h)	71.1° 05:35	5.43	79%	115.5°
2043-05-19 Tue	74	—	unknown	00:45–04:00 (good, 3.25 h)	71.1° 05:35	5.38	86%	108.0°
2043-05-20 Wed	68	—	unknown	00:50–04:00 (good, 3.17 h)	71.1° 05:30	5.33	92%	100.1°
2043-05-21 Thu	61	—	unknown	00:55–04:00 (good, 3.08 h)	71.1° 05:25	5.28	96%	92.0°
2043-05-22 Fri	54	—	unknown	01:25–03:55 (good, 2.5 h)	71.1° 05:20	5.23	99%	83.9°
2043-05-23 Sat	48	—	unknown	01:55–03:55 (good, 2.0 h)	71.1° 05:15	5.18	100%	75.9°
2043-05-24 Sun	44	—	unknown	02:20–03:55 (good, 1.58 h)	71.1° 05:15	5.13	99%	68.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-05-13&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.