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: 06-10 (100), 06-11 (100), 06-12 (100), 06-13 (100), 06-14 (100) — by astronomy; check the weather when the night is within four days.

2034-05-19astronomy score per night — click a bar for that night2034-06-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-05-19 Fri	94	—	unknown	00:30–04:00 (good, 3.5 h)	71.1° 05:30	5.37	5%	125.9°
2034-05-20 Sat	96	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:30	5.32	11%	134.4°
2034-05-21 Sun	98	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:25	5.27	20%	140.1°
2034-05-22 Mon	98	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.22	29%	141.9°
2034-05-23 Tue	99	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:15	5.17	39%	139.8°
2034-05-24 Wed	99	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:10	5.13	49%	134.7°
2034-05-25 Thu	99	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:10	5.08	59%	127.6°
2034-05-26 Fri	98	—	unknown	00:10–03:50 (good, 3.67 h)	71.1° 05:05	5.04	69%	119.4°
2034-05-27 Sat	96	—	unknown	00:10–03:50 (good, 3.67 h)	71.1° 05:00	4.99	77%	110.6°
2034-05-28 Sun	79	—	unknown	00:15–03:50 (good, 3.58 h)	71.1° 04:55	4.95	85%	101.5°
2034-05-29 Mon	69	—	unknown	00:20–03:50 (good, 3.5 h)	71.1° 04:55	4.91	91%	92.2°
2034-05-30 Tue	59	—	unknown	01:05–03:45 (good, 2.67 h)	71.1° 04:50	4.87	95%	82.9°
2034-05-31 Wed	50	—	unknown	01:55–03:45 (good, 1.83 h)	71.1° 04:45	4.83	98%	73.7°
2034-06-01 Thu	42	—	unknown	02:50–03:45 (good, 0.92 h)	71.1° 04:40	4.79	100%	64.8°
2034-06-02 Fri	36	—	unknown	23:25–03:45 (marginal, 4.33 h)	71.1° 04:35	4.76	99%	56.3°
2034-06-03 Sat	32	—	unknown	23:15–03:45 (marginal, 4.5 h)	71.1° 04:35	4.72	97%	48.8°
2034-06-04 Sun	33	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 04:30	4.69	93%	42.7°
2034-06-05 Mon	41	—	unknown	23:00–03:40 (marginal, 4.67 h)	71.1° 04:25	4.66	87%	38.9°
2034-06-06 Tue	64	—	unknown	23:20–00:05 (good, 0.75 h)	71.1° 04:20	4.63	79%	38.4°
2034-06-07 Wed	78	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.61	70%	41.5°
2034-06-08 Thu	92	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:15	4.58	60%	47.5°
2034-06-09 Fri	96	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:10	4.56	49%	55.8°
2034-06-10 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	71.1° 04:05	4.53	38%	65.6°
2034-06-11 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.51	27%	76.3°
2034-06-12 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.5	17%	87.7°
2034-06-13 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:55	4.48	9%	99.3°
2034-06-14 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:50	4.47	4%	110.8°
2034-06-15 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.45	1%	121.6°
2034-06-16 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.44	0%	131.0°
2034-06-17 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.43	3%	138.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-05-19&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.