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.

2027-10-01astronomy score per night — click a bar for that night2027-10-30

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-01 Fri	—	unknown	—	50.2° 13:10	9.17	4%	28.4°
2027-10-02 Sat	—	unknown	—	50.2° 13:10	9.22	10%	41.5°
2027-10-03 Sun	—	unknown	—	50.2° 13:05	9.26	17%	54.5°
2027-10-04 Mon	—	unknown	—	50.2° 13:00	9.31	26%	67.1°
2027-10-05 Tue	—	unknown	—	50.2° 12:55	9.36	35%	79.4°
2027-10-06 Wed	—	unknown	—	50.2° 12:50	9.4	44%	91.5°
2027-10-07 Thu	—	unknown	—	50.2° 12:50	9.45	54%	103.3°
2027-10-08 Fri	—	unknown	—	50.2° 12:45	9.5	63%	115.0°
2027-10-09 Sat	—	unknown	—	50.2° 12:40	9.54	72%	126.7°
2027-10-10 Sun	—	unknown	—	50.2° 12:35	9.59	80%	138.3°
2027-10-11 Mon	—	unknown	—	50.2° 12:35	9.63	87%	149.8°
2027-10-12 Tue	—	unknown	—	50.2° 12:30	9.68	93%	161.0°
2027-10-13 Wed	—	unknown	—	50.2° 12:25	9.72	97%	170.0°
2027-10-14 Thu	—	unknown	—	50.2° 12:20	9.77	99%	167.9°
2027-10-15 Fri	—	unknown	—	50.2° 12:15	9.81	100%	157.3°
2027-10-16 Sat	—	unknown	—	50.2° 12:15	9.85	98%	145.0°
2027-10-17 Sun	—	unknown	—	50.2° 12:10	9.9	94%	132.1°
2027-10-18 Mon	—	unknown	—	50.2° 12:05	9.94	88%	118.8°
2027-10-19 Tue	—	unknown	—	50.2° 12:00	9.98	80%	105.4°
2027-10-20 Wed	—	unknown	—	50.2° 11:55	10.02	70%	91.8°
2027-10-21 Thu	—	unknown	—	50.2° 11:50	10.07	59%	78.0°
2027-10-22 Fri	—	unknown	—	50.2° 11:45	10.11	48%	64.1°
2027-10-23 Sat	—	unknown	—	50.2° 11:40	10.15	36%	50.2°
2027-10-24 Sun	—	unknown	—	50.2° 11:40	10.19	26%	36.4°
2027-10-25 Mon	—	unknown	—	50.2° 11:35	10.23	16%	22.9°
2027-10-26 Tue	—	unknown	—	50.2° 11:30	10.27	9%	11.3°
2027-10-27 Wed	—	unknown	—	50.2° 11:25	10.31	4%	11.6°
2027-10-28 Thu	—	unknown	—	50.2° 11:20	10.34	1%	23.1°
2027-10-29 Fri	—	unknown	—	50.2° 11:20	10.38	0%	36.2°
2027-10-30 Sat	—	unknown	—	50.2° 10:15	10.42	2%	49.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-01&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.