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 Vega: 06-22 (100), 06-23 (100), 06-24 (100), 06-25 (100), 06-26 (100) — by astronomy; check the weather when the night is within four days.

2027-06-16astronomy score per night — click a bar for that night2027-07-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-06-16 Wed	76	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.44	96%	74.4°
2027-06-17 Thu	67	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:15	4.44	99%	70.3°
2027-06-18 Fri	60	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:10	4.43	100%	67.0°
2027-06-19 Sat	59	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:05	4.42	99%	64.8°
2027-06-20 Sun	62	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 02:05	4.42	97%	63.8°
2027-06-21 Mon	69	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 02:00	4.42	92%	63.9°
2027-06-22 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:55	4.42	87%	65.3°
2027-06-23 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:50	4.43	80%	67.7°
2027-06-24 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:45	4.43	72%	71.1°
2027-06-25 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:45	4.44	62%	75.3°
2027-06-26 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:40	4.45	53%	80.2°
2027-06-27 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:35	4.46	43%	85.6°
2027-06-28 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.1° 01:30	4.48	32%	91.3°
2027-06-29 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 01:30	4.49	23%	97.2°
2027-06-30 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:25	4.51	14%	102.9°
2027-07-01 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:20	4.53	7%	108.1°
2027-07-02 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:15	4.55	2%	112.4°
2027-07-03 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:10	4.58	0%	115.3°
2027-07-04 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:10	4.6	1%	116.3°
2027-07-05 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.1° 01:05	4.63	5%	115.4°
2027-07-06 Tue	100	—	unknown	23:10–03:50 (good, 4.67 h)	87.1° 01:00	4.66	11%	112.7°
2027-07-07 Wed	100	—	unknown	23:10–03:50 (good, 4.67 h)	87.1° 00:55	4.69	20%	108.6°
2027-07-08 Thu	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.1° 00:50	4.72	30%	103.5°
2027-07-09 Fri	100	—	unknown	23:05–03:50 (good, 4.75 h)	87.1° 00:50	4.76	41%	97.8°
2027-07-10 Sat	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.1° 00:45	4.79	52%	91.9°
2027-07-11 Sun	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.1° 00:40	4.83	62%	86.1°
2027-07-12 Mon	100	—	unknown	23:05–03:55 (good, 4.83 h)	87.1° 00:35	4.87	72%	80.6°
2027-07-13 Tue	100	—	unknown	23:00–03:55 (good, 4.92 h)	87.1° 00:35	4.9	80%	75.6°
2027-07-14 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:30	4.95	88%	71.3°
2027-07-15 Thu	97	—	unknown	23:00–04:00 (good, 5.0 h)	87.1° 00:25	4.99	93%	67.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-06-16&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.