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.

2027-06-29astronomy score per night — click a bar for that night2027-07-28

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-06-29 Tue	—	unknown	—	42.9° 12:30	4.49	23%	52.7°
2027-06-30 Wed	—	unknown	—	42.9° 12:25	4.51	14%	43.2°
2027-07-01 Thu	—	unknown	—	42.9° 12:20	4.53	7%	35.8°
2027-07-02 Fri	—	unknown	—	42.9° 12:15	4.55	2%	32.6°
2027-07-03 Sat	—	unknown	—	42.9° 12:15	4.58	0%	35.1°
2027-07-04 Sun	—	unknown	—	42.9° 12:10	4.6	1%	42.5°
2027-07-05 Mon	—	unknown	—	42.9° 12:05	4.63	5%	52.8°
2027-07-06 Tue	—	unknown	—	42.9° 12:00	4.66	11%	64.4°
2027-07-07 Wed	—	unknown	—	42.9° 11:55	4.69	20%	76.4°
2027-07-08 Thu	—	unknown	—	42.9° 11:50	4.72	30%	88.4°
2027-07-09 Fri	—	unknown	—	42.9° 11:45	4.76	41%	100.0°
2027-07-10 Sat	—	unknown	—	42.9° 11:40	4.79	52%	111.2°
2027-07-11 Sun	—	unknown	—	42.9° 11:40	4.83	62%	121.6°
2027-07-12 Mon	—	unknown	—	42.9° 11:35	4.87	72%	131.1°
2027-07-13 Tue	—	unknown	—	42.9° 11:30	4.9	80%	139.1°
2027-07-14 Wed	—	unknown	—	42.9° 11:25	4.95	88%	144.9°
2027-07-15 Thu	—	unknown	—	42.9° 11:20	4.99	93%	147.4°
2027-07-16 Fri	—	unknown	—	42.9° 11:20	5.03	97%	146.0°
2027-07-17 Sat	—	unknown	—	42.9° 11:15	5.07	100%	141.3°
2027-07-18 Sun	—	unknown	—	42.9° 11:10	5.12	100%	134.4°
2027-07-19 Mon	—	unknown	—	42.9° 11:05	5.17	98%	126.0°
2027-07-20 Tue	—	unknown	—	42.9° 11:00	5.21	95%	116.8°
2027-07-21 Wed	—	unknown	—	42.9° 11:00	5.26	91%	107.1°
2027-07-22 Thu	—	unknown	—	42.9° 10:55	5.31	84%	97.1°
2027-07-23 Fri	—	unknown	—	42.9° 10:50	5.36	77%	86.9°
2027-07-24 Sat	—	unknown	—	42.9° 10:45	5.41	68%	76.6°
2027-07-25 Sun	—	unknown	—	42.9° 10:45	5.46	58%	66.3°
2027-07-26 Mon	—	unknown	—	42.9° 10:40	5.51	48%	56.1°
2027-07-27 Tue	—	unknown	—	42.9° 10:35	5.56	37%	46.5°
2027-07-28 Wed	—	unknown	—	42.9° 10:30	5.62	27%	38.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-06-29&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.