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.

2046-05-01astronomy score per night — click a bar for that night2046-05-30

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-05-01 Tue	—	unknown	—	72.6° 14:30	6.35	16%	64.9°
2046-05-02 Wed	—	unknown	—	72.6° 14:30	6.3	10%	53.0°
2046-05-03 Thu	—	unknown	—	72.6° 14:25	6.24	5%	41.0°
2046-05-04 Fri	—	unknown	—	72.6° 14:20	6.18	2%	28.8°
2046-05-05 Sat	—	unknown	—	72.6° 14:15	6.12	0%	16.4°
2046-05-06 Sun	—	unknown	—	72.6° 14:10	6.07	1%	3.8°
2046-05-07 Mon	—	unknown	—	72.6° 14:10	6.01	4%	9.0°
2046-05-08 Tue	—	unknown	—	72.6° 14:05	5.95	8%	22.0°
2046-05-09 Wed	—	unknown	—	72.6° 14:00	5.9	15%	35.2°
2046-05-10 Thu	—	unknown	—	72.6° 13:55	5.84	24%	48.7°
2046-05-11 Fri	—	unknown	—	72.6° 13:55	5.79	33%	62.3°
2046-05-12 Sat	—	unknown	—	72.6° 13:50	5.73	44%	76.1°
2046-05-13 Sun	—	unknown	—	72.6° 13:45	5.68	56%	90.2°
2046-05-14 Mon	—	unknown	—	72.6° 13:40	5.62	67%	104.4°
2046-05-15 Tue	—	unknown	—	72.6° 13:35	5.57	77%	118.8°
2046-05-16 Wed	—	unknown	—	72.6° 13:35	5.52	86%	133.3°
2046-05-17 Thu	—	unknown	—	72.6° 13:30	5.46	93%	147.9°
2046-05-18 Fri	—	unknown	—	72.6° 13:25	5.41	98%	162.3°
2046-05-19 Sat	—	unknown	—	72.6° 13:20	5.36	100%	176.6°
2046-05-20 Sun	—	unknown	—	72.6° 13:15	5.31	99%	169.3°
2046-05-21 Mon	—	unknown	—	72.6° 13:15	5.26	96%	155.7°
2046-05-22 Tue	—	unknown	—	72.6° 13:10	5.21	91%	142.3°
2046-05-23 Wed	—	unknown	—	72.6° 13:05	5.17	84%	129.4°
2046-05-24 Thu	—	unknown	—	72.6° 13:00	5.12	76%	116.8°
2046-05-25 Fri	—	unknown	—	72.6° 13:00	5.07	67%	104.4°
2046-05-26 Sat	—	unknown	—	72.6° 12:55	5.03	57%	92.4°
2046-05-27 Sun	—	unknown	—	72.6° 12:50	4.99	48%	80.4°
2046-05-28 Mon	—	unknown	—	72.6° 12:45	4.94	39%	68.6°
2046-05-29 Tue	—	unknown	—	72.6° 12:40	4.9	30%	56.7°
2046-05-30 Wed	—	unknown	—	72.6° 12:40	4.86	21%	44.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-05-01&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.