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 Triangulum Pinwheel: 05-29 (1), 05-30 (1) — by astronomy; check the weather when the night is within four days.

2031-05-01astronomy score per night — click a bar for that night2031-05-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-05-01 Thu	0	—	unknown	—	79.1° 12:20	6.38	70%	122.0°
2031-05-02 Fri	0	—	unknown	—	79.1° 12:15	6.32	79%	133.8°
2031-05-03 Sat	0	—	unknown	—	79.1° 12:10	6.26	87%	145.5°
2031-05-04 Sun	0	—	unknown	—	79.1° 12:10	6.2	94%	156.2°
2031-05-05 Mon	0	—	unknown	—	79.1° 12:05	6.14	98%	162.7°
2031-05-06 Tue	0	—	unknown	—	79.1° 12:00	6.09	100%	159.5°
2031-05-07 Wed	0	—	unknown	—	79.1° 11:55	6.03	99%	149.2°
2031-05-08 Thu	0	—	unknown	—	79.1° 11:50	5.97	96%	136.4°
2031-05-09 Fri	0	—	unknown	—	79.1° 11:45	5.92	89%	122.7°
2031-05-10 Sat	0	—	unknown	—	79.1° 11:40	5.86	81%	108.8°
2031-05-11 Sun	0	—	unknown	—	79.1° 11:35	5.81	71%	95.0°
2031-05-12 Mon	0	—	unknown	—	79.1° 11:35	5.75	60%	81.4°
2031-05-13 Tue	0	—	unknown	—	79.1° 11:30	5.7	48%	68.1°
2031-05-14 Wed	0	—	unknown	—	79.1° 11:25	5.64	38%	55.2°
2031-05-15 Thu	0	—	unknown	—	79.1° 11:20	5.59	27%	42.8°
2031-05-16 Fri	0	—	unknown	—	79.1° 11:15	5.54	18%	31.4°
2031-05-17 Sat	0	—	unknown	—	79.1° 11:15	5.48	11%	21.8°
2031-05-18 Sun	0	—	unknown	—	79.1° 11:10	5.43	6%	17.1°
2031-05-19 Mon	0	—	unknown	—	79.1° 11:05	5.38	2%	20.5°
2031-05-20 Tue	0	—	unknown	—	79.1° 11:00	5.33	0%	29.0°
2031-05-21 Wed	0	—	unknown	—	79.1° 11:00	5.28	0%	39.4°
2031-05-22 Thu	0	—	unknown	—	79.1° 10:55	5.23	2%	50.3°
2031-05-23 Fri	0	—	unknown	—	79.1° 10:50	5.18	6%	61.4°
2031-05-24 Sat	0	—	unknown	—	79.1° 10:45	5.14	12%	72.7°
2031-05-25 Sun	0	—	unknown	—	79.1° 10:40	5.09	18%	83.9°
2031-05-26 Mon	0	—	unknown	—	79.1° 10:40	5.05	26%	95.3°
2031-05-27 Tue	0	—	unknown	—	79.1° 10:35	5.0	35%	106.6°
2031-05-28 Wed	0	—	unknown	—	79.1° 10:30	4.96	45%	118.1°
2031-05-29 Thu	1	—	unknown	—	79.1° 10:25	4.92	55%	129.7°
2031-05-30 Fri	1	—	unknown	—	79.1° 10:20	4.88	65%	141.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-05-01&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.