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

2039-05-01astronomy score per night — click a bar for that night2039-05-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-05-01 Sun	0	—	unknown	—	79.2° 12:20	6.37	53%	100.0°
2039-05-02 Mon	0	—	unknown	—	79.2° 12:15	6.31	64%	111.8°
2039-05-03 Tue	0	—	unknown	—	79.2° 12:15	6.26	74%	123.7°
2039-05-04 Wed	0	—	unknown	—	79.2° 12:10	6.2	83%	135.5°
2039-05-05 Thu	0	—	unknown	—	79.2° 12:05	6.14	91%	146.5°
2039-05-06 Fri	0	—	unknown	—	79.2° 12:00	6.08	96%	154.7°
2039-05-07 Sat	0	—	unknown	—	79.2° 11:55	6.03	100%	156.3°
2039-05-08 Sun	0	—	unknown	—	79.2° 11:50	5.97	100%	149.7°
2039-05-09 Mon	0	—	unknown	—	79.2° 11:45	5.91	97%	138.7°
2039-05-10 Tue	0	—	unknown	—	79.2° 11:40	5.86	91%	126.0°
2039-05-11 Wed	0	—	unknown	—	79.2° 11:35	5.8	83%	112.8°
2039-05-12 Thu	0	—	unknown	—	79.2° 11:35	5.75	74%	99.7°
2039-05-13 Fri	0	—	unknown	—	79.2° 11:30	5.69	63%	86.9°
2039-05-14 Sat	0	—	unknown	—	79.2° 11:25	5.64	52%	74.5°
2039-05-15 Sun	0	—	unknown	—	79.2° 11:20	5.59	42%	62.6°
2039-05-16 Mon	0	—	unknown	—	79.2° 11:20	5.53	32%	51.4°
2039-05-17 Tue	0	—	unknown	—	79.2° 11:15	5.48	23%	40.9°
2039-05-18 Wed	0	—	unknown	—	79.2° 11:10	5.43	15%	31.8°
2039-05-19 Thu	0	—	unknown	—	79.2° 11:05	5.38	9%	25.3°
2039-05-20 Fri	0	—	unknown	—	79.2° 11:00	5.33	4%	23.3°
2039-05-21 Sat	0	—	unknown	—	79.2° 11:00	5.28	1%	26.8°
2039-05-22 Sun	0	—	unknown	—	79.2° 10:55	5.23	0%	34.0°
2039-05-23 Mon	0	—	unknown	—	79.2° 10:50	5.18	1%	43.1°
2039-05-24 Tue	0	—	unknown	—	79.2° 10:45	5.13	3%	53.1°
2039-05-25 Wed	0	—	unknown	—	79.2° 10:40	5.09	7%	63.6°
2039-05-26 Thu	0	—	unknown	—	79.2° 10:40	5.04	13%	74.4°
2039-05-27 Fri	0	—	unknown	—	79.2° 10:35	5.0	20%	85.5°
2039-05-28 Sat	0	—	unknown	—	79.2° 10:30	4.96	28%	96.8°
2039-05-29 Sun	0	—	unknown	—	79.2° 10:25	4.92	38%	108.2°
2039-05-30 Mon	1	—	unknown	—	79.2° 10:20	4.88	48%	119.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-05-01&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.