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: 06-06 (100), 06-07 (100), 06-08 (100), 06-09 (100), 06-10 (100) — by astronomy; check the weather when the night is within four days.

2027-06-06astronomy score per night — click a bar for that night2027-07-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-06-06 Sun	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:20	4.64	6%	130.6°
2027-06-07 Mon	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:20	4.61	14%	136.0°
2027-06-08 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.59	23%	137.7°
2027-06-09 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:10	4.56	33%	135.4°
2027-06-10 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:05	4.54	44%	129.9°
2027-06-11 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.52	55%	122.4°
2027-06-12 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.5	66%	113.7°
2027-06-13 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:55	4.48	76%	104.5°
2027-06-14 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:50	4.47	84%	95.1°
2027-06-15 Tue	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 03:45	4.45	91%	85.7°
2027-06-16 Wed	71	—	unknown	00:05–03:40 (good, 3.58 h)	71.1° 03:45	4.44	96%	76.5°
2027-06-17 Thu	59	—	unknown	00:50–03:40 (good, 2.83 h)	71.1° 03:40	4.44	99%	67.8°
2027-06-18 Fri	50	—	unknown	01:40–03:40 (good, 2.0 h)	71.1° 03:35	4.43	100%	59.8°
2027-06-19 Sat	44	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:30	4.42	99%	52.8°
2027-06-20 Sun	41	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:25	4.42	97%	47.1°
2027-06-21 Mon	43	—	unknown	23:15–03:40 (marginal, 4.42 h)	71.1° 03:25	4.42	92%	43.5°
2027-06-22 Tue	70	—	unknown	23:15–23:30 (good, 0.25 h)	71.1° 03:20	4.42	87%	42.3°
2027-06-23 Wed	80	—	unknown	23:15–02:35 (good, 3.33 h)	71.1° 03:15	4.43	80%	43.7°
2027-06-24 Thu	90	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.43	72%	47.6°
2027-06-25 Fri	95	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.44	62%	53.4°
2027-06-26 Sat	98	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.45	53%	60.7°
2027-06-27 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.46	43%	69.1°
2027-06-28 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	32%	78.4°
2027-06-29 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.49	23%	88.2°
2027-06-30 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:50	4.51	14%	98.4°
2027-07-01 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.53	7%	108.7°
2027-07-02 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.55	2%	118.7°
2027-07-03 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.58	0%	127.6°
2027-07-04 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.6	1%	134.3°
2027-07-05 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.63	5%	137.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-06-06&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.