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 V1057 Cyg: 06-15 (100), 06-27 (100), 06-28 (100), 06-29 (100), 06-30 (100) — by astronomy; check the weather when the night is within four days.

2027-06-15astronomy score per night — click a bar for that night2027-07-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-06-15 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:45	4.45	91%	105.0°
2027-06-16 Wed	84	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:40	4.44	96%	98.2°
2027-06-17 Thu	79	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.44	99%	91.1°
2027-06-18 Fri	70	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.43	100%	84.1°
2027-06-19 Sat	63	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.42	99%	77.4°
2027-06-20 Sun	59	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:25	4.42	97%	71.1°
2027-06-21 Mon	59	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:20	4.42	92%	65.5°
2027-06-22 Tue	78	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.42	87%	60.8°
2027-06-23 Wed	85	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.43	80%	57.2°
2027-06-24 Thu	91	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:10	4.43	72%	55.2°
2027-06-25 Fri	94	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:05	4.44	62%	54.9°
2027-06-26 Sat	97	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:00	4.45	53%	56.3°
2027-06-27 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.46	43%	59.6°
2027-06-28 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.48	32%	64.4°
2027-06-29 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 03:50	4.49	23%	70.6°
2027-06-30 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:45	4.51	14%	78.0°
2027-07-01 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.53	7%	86.0°
2027-07-02 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.55	2%	94.5°
2027-07-03 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:35	4.58	0%	103.0°
2027-07-04 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:30	4.6	1%	110.8°
2027-07-05 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:25	4.63	5%	117.5°
2027-07-06 Tue	100	—	unknown	23:10–03:50 (good, 4.67 h)	87.3° 03:20	4.66	11%	122.4°
2027-07-07 Wed	100	—	unknown	23:10–03:50 (good, 4.67 h)	87.3° 03:20	4.69	20%	125.0°
2027-07-08 Thu	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.3° 03:15	4.72	30%	125.0°
2027-07-09 Fri	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.3° 03:10	4.76	41%	122.7°
2027-07-10 Sat	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 03:05	4.79	52%	118.5°
2027-07-11 Sun	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 03:00	4.83	62%	113.0°
2027-07-12 Mon	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 03:00	4.87	72%	106.7°
2027-07-13 Tue	100	—	unknown	23:00–03:55 (good, 4.92 h)	87.3° 02:55	4.9	80%	99.9°
2027-07-14 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:50	4.95	88%	92.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-06-15&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.