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.

2034-04-26astronomy score per night — click a bar for that night2034-05-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-04-26 Wed	—	unknown	—	42.9° 16:40	6.65	65%	63.1°
2034-04-27 Thu	—	unknown	—	42.9° 16:35	6.59	74%	74.4°
2034-04-28 Fri	—	unknown	—	42.9° 16:30	6.53	82%	85.6°
2034-04-29 Sat	—	unknown	—	42.9° 16:30	6.48	89%	96.7°
2034-04-30 Sun	—	unknown	—	42.9° 16:25	6.42	94%	107.6°
2034-05-01 Mon	—	unknown	—	42.9° 16:20	6.36	98%	118.3°
2034-05-02 Tue	—	unknown	—	42.9° 16:15	6.3	100%	128.7°
2034-05-03 Wed	—	unknown	—	42.9° 16:10	6.24	100%	138.5°
2034-05-04 Thu	—	unknown	—	42.9° 16:10	6.19	98%	147.3°
2034-05-05 Fri	—	unknown	—	42.9° 16:05	6.13	95%	153.9°
2034-05-06 Sat	—	unknown	—	42.9° 16:00	6.07	90%	156.4°
2034-05-07 Sun	—	unknown	—	42.9° 15:55	6.02	83%	153.4°
2034-05-08 Mon	—	unknown	—	42.9° 15:50	5.96	75%	146.1°
2034-05-09 Tue	—	unknown	—	42.9° 15:50	5.9	66%	136.6°
2034-05-10 Wed	—	unknown	—	42.9° 15:45	5.85	56%	125.7°
2034-05-11 Thu	—	unknown	—	42.9° 15:40	5.79	45%	114.0°
2034-05-12 Fri	—	unknown	—	42.9° 15:35	5.74	34%	101.7°
2034-05-13 Sat	—	unknown	—	42.9° 15:35	5.68	24%	88.9°
2034-05-14 Sun	—	unknown	—	42.9° 15:30	5.63	15%	75.6°
2034-05-15 Mon	—	unknown	—	42.9° 15:25	5.57	7%	62.2°
2034-05-16 Tue	—	unknown	—	42.9° 15:20	5.52	2%	49.0°
2034-05-17 Wed	—	unknown	—	42.9° 15:15	5.47	0%	36.8°
2034-05-18 Thu	—	unknown	—	42.9° 15:15	5.42	1%	27.2°
2034-05-19 Fri	—	unknown	—	42.9° 15:10	5.37	5%	23.7°
2034-05-20 Sat	—	unknown	—	42.9° 15:05	5.32	11%	28.1°
2034-05-21 Sun	—	unknown	—	42.9° 15:00	5.27	20%	37.3°
2034-05-22 Mon	—	unknown	—	42.9° 14:55	5.22	29%	48.4°
2034-05-23 Tue	—	unknown	—	42.9° 14:55	5.17	39%	59.8°
2034-05-24 Wed	—	unknown	—	42.9° 14:50	5.13	49%	71.4°
2034-05-25 Thu	—	unknown	—	42.9° 14:45	5.08	59%	82.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-04-26&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.