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.

2035-05-07astronomy score per night — click a bar for that night2035-06-05

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-05-07 Mon	—	unknown	—	42.9° 15:55	6.03	0%	40.6°
2035-05-08 Tue	—	unknown	—	42.9° 15:55	5.97	2%	30.0°
2035-05-09 Wed	—	unknown	—	42.9° 15:50	5.92	7%	24.0°
2035-05-10 Thu	—	unknown	—	42.9° 15:45	5.86	14%	26.0°
2035-05-11 Fri	—	unknown	—	42.9° 15:40	5.81	23%	34.4°
2035-05-12 Sat	—	unknown	—	42.9° 15:40	5.75	33%	45.4°
2035-05-13 Sun	—	unknown	—	42.9° 15:35	5.7	44%	57.4°
2035-05-14 Mon	—	unknown	—	42.9° 15:30	5.64	55%	69.5°
2035-05-15 Tue	—	unknown	—	42.9° 15:25	5.59	66%	81.6°
2035-05-16 Wed	—	unknown	—	42.9° 15:20	5.53	75%	93.4°
2035-05-17 Thu	—	unknown	—	42.9° 15:20	5.48	83%	105.0°
2035-05-18 Fri	—	unknown	—	42.9° 15:15	5.43	90%	116.3°
2035-05-19 Sat	—	unknown	—	42.9° 15:10	5.38	95%	127.1°
2035-05-20 Sun	—	unknown	—	42.9° 15:05	5.33	98%	137.3°
2035-05-21 Mon	—	unknown	—	42.9° 15:00	5.28	100%	146.3°
2035-05-22 Tue	—	unknown	—	42.9° 15:00	5.23	99%	153.3°
2035-05-23 Wed	—	unknown	—	42.9° 14:55	5.18	97%	156.2°
2035-05-24 Thu	—	unknown	—	42.9° 14:50	5.14	93%	153.9°
2035-05-25 Fri	—	unknown	—	42.9° 14:45	5.09	88%	147.4°
2035-05-26 Sat	—	unknown	—	42.9° 14:45	5.05	81%	138.7°
2035-05-27 Sun	—	unknown	—	42.9° 14:40	5.0	73%	128.8°
2035-05-28 Mon	—	unknown	—	42.9° 14:35	4.96	64%	118.1°
2035-05-29 Tue	—	unknown	—	42.9° 14:30	4.92	54%	106.9°
2035-05-30 Wed	—	unknown	—	42.9° 14:25	4.88	44%	95.3°
2035-05-31 Thu	—	unknown	—	42.9° 14:25	4.84	33%	83.3°
2035-06-01 Fri	—	unknown	—	42.9° 14:20	4.8	24%	70.9°
2035-06-02 Sat	—	unknown	—	42.9° 14:15	4.77	15%	58.3°
2035-06-03 Sun	—	unknown	—	42.9° 14:10	4.73	7%	45.8°
2035-06-04 Mon	—	unknown	—	42.9° 14:05	4.7	2%	34.3°
2035-06-05 Tue	—	unknown	—	42.9° 14:05	4.67	0%	25.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-07&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.