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.

2043-04-06astronomy score per night — click a bar for that night2043-05-05

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-04-06 Mon	—	unknown	—	79.2° 14:00	7.81	11%	58.7°
2043-04-07 Tue	—	unknown	—	79.2° 13:55	7.76	5%	45.4°
2043-04-08 Wed	—	unknown	—	79.2° 13:50	7.7	1%	32.4°
2043-04-09 Thu	—	unknown	—	79.2° 13:45	7.64	0%	21.3°
2043-04-10 Fri	—	unknown	—	79.2° 13:45	7.59	2%	17.2°
2043-04-11 Sat	—	unknown	—	79.2° 13:40	7.53	7%	24.2°
2043-04-12 Sun	—	unknown	—	79.2° 13:35	7.47	14%	36.1°
2043-04-13 Mon	—	unknown	—	79.2° 13:30	7.41	23%	49.2°
2043-04-14 Tue	—	unknown	—	79.2° 13:25	7.36	34%	62.4°
2043-04-15 Wed	—	unknown	—	79.2° 13:25	7.3	45%	75.5°
2043-04-16 Thu	—	unknown	—	79.2° 13:20	7.24	55%	88.3°
2043-04-17 Fri	—	unknown	—	79.2° 13:15	7.18	66%	100.7°
2043-04-18 Sat	—	unknown	—	79.2° 13:10	7.13	75%	112.9°
2043-04-19 Sun	—	unknown	—	79.2° 13:10	7.07	83%	124.6°
2043-04-20 Mon	—	unknown	—	79.2° 13:05	7.01	90%	135.9°
2043-04-21 Tue	—	unknown	—	79.2° 13:00	6.95	95%	146.6°
2043-04-22 Wed	—	unknown	—	79.2° 12:55	6.89	98%	156.0°
2043-04-23 Thu	—	unknown	—	79.2° 12:50	6.84	100%	162.1°
2043-04-24 Fri	—	unknown	—	79.2° 12:50	6.78	100%	161.7°
2043-04-25 Sat	—	unknown	—	79.2° 12:45	6.72	98%	155.0°
2043-04-26 Sun	—	unknown	—	79.2° 12:40	6.66	94%	145.5°
2043-04-27 Mon	—	unknown	—	79.2° 12:35	6.6	88%	135.0°
2043-04-28 Tue	—	unknown	—	79.2° 12:30	6.54	82%	123.9°
2043-04-29 Wed	—	unknown	—	79.2° 12:30	6.49	74%	112.5°
2043-04-30 Thu	—	unknown	—	79.2° 12:25	6.43	64%	100.8°
2043-05-01 Fri	—	unknown	—	79.2° 12:20	6.37	55%	88.8°
2043-05-02 Sat	—	unknown	—	79.2° 12:15	6.31	44%	76.5°
2043-05-03 Sun	—	unknown	—	79.2° 12:15	6.25	34%	63.8°
2043-05-04 Mon	—	unknown	—	79.2° 12:10	6.2	24%	50.9°
2043-05-05 Tue	—	unknown	—	79.2° 12:05	6.14	15%	37.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-04-06&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.