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: 05-31 (1), 06-01 (1), 06-02 (1), 06-03 (1), 06-04 (1) — by astronomy; check the weather when the night is within four days.

2037-05-07astronomy score per night — click a bar for that night2037-06-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-05-07 Thu	0	—	unknown	—	79.2° 11:50	6.0	43%	69.7°
2037-05-08 Fri	0	—	unknown	—	79.2° 11:45	5.94	34%	59.2°
2037-05-09 Sat	0	—	unknown	—	79.2° 11:45	5.89	25%	49.0°
2037-05-10 Sun	0	—	unknown	—	79.2° 11:40	5.83	18%	39.5°
2037-05-11 Mon	0	—	unknown	—	79.2° 11:35	5.78	11%	31.2°
2037-05-12 Tue	0	—	unknown	—	79.2° 11:30	5.72	6%	25.5°
2037-05-13 Wed	0	—	unknown	—	79.1° 11:25	5.67	2%	24.8°
2037-05-14 Thu	0	—	unknown	—	79.2° 11:25	5.61	0%	29.6°
2037-05-15 Fri	0	—	unknown	—	79.2° 11:20	5.56	1%	38.1°
2037-05-16 Sat	0	—	unknown	—	79.2° 11:15	5.51	3%	48.5°
2037-05-17 Sun	0	—	unknown	—	79.2° 11:10	5.46	8%	60.0°
2037-05-18 Mon	0	—	unknown	—	79.1° 11:10	5.4	15%	72.1°
2037-05-19 Tue	0	—	unknown	—	79.2° 11:05	5.35	24%	84.6°
2037-05-20 Wed	0	—	unknown	—	79.2° 11:00	5.3	34%	97.2°
2037-05-21 Thu	0	—	unknown	—	79.2° 10:55	5.25	45%	109.9°
2037-05-22 Fri	0	—	unknown	—	79.2° 10:50	5.21	56%	122.5°
2037-05-23 Sat	0	—	unknown	—	79.2° 10:50	5.16	68%	134.5°
2037-05-24 Sun	0	—	unknown	—	79.2° 10:45	5.11	78%	145.4°
2037-05-25 Mon	0	—	unknown	—	79.2° 10:40	5.07	87%	153.3°
2037-05-26 Tue	0	—	unknown	—	79.2° 10:35	5.02	93%	155.4°
2037-05-27 Wed	0	—	unknown	—	79.1° 10:30	4.98	98%	150.4°
2037-05-28 Thu	0	—	unknown	—	79.2° 10:30	4.94	100%	141.1°
2037-05-29 Fri	0	—	unknown	—	79.2° 10:25	4.9	99%	130.2°
2037-05-30 Sat	0	—	unknown	—	79.2° 10:20	4.86	96%	118.7°
2037-05-31 Sun	1	—	unknown	—	79.2° 10:15	4.82	92%	107.1°
2037-06-01 Mon	1	—	unknown	—	79.1° 10:15	4.78	85%	95.7°
2037-06-02 Tue	1	—	unknown	—	79.2° 10:10	4.75	77%	84.4°
2037-06-03 Wed	1	—	unknown	—	79.2° 10:05	4.72	69%	73.4°
2037-06-04 Thu	1	—	unknown	—	79.2° 10:00	4.68	60%	62.7°
2037-06-05 Fri	1	—	unknown	—	79.2° 09:55	4.65	50%	52.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-05-07&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.