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 Andromeda Galaxy: 05-06 (2), 05-07 (2), 05-08 (2), 05-09 (2), 05-10 (2) — by astronomy; check the weather when the night is within four days.

2047-04-11astronomy score per night — click a bar for that night2047-05-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-04-11 Thu	0	—	unknown	—	89.6° 12:50	7.53	96%	147.8°
2047-04-12 Fri	0	—	unknown	—	89.8° 12:45	7.47	91%	139.1°
2047-04-13 Sat	0	—	unknown	—	89.8° 12:40	7.41	83%	128.1°
2047-04-14 Sun	0	—	unknown	—	89.7° 12:35	7.36	73%	116.4°
2047-04-15 Mon	0	—	unknown	—	89.5° 12:30	7.3	63%	104.5°
2047-04-16 Tue	0	—	unknown	—	89.7° 12:30	7.24	52%	92.8°
2047-04-17 Wed	0	—	unknown	—	89.8° 12:25	7.18	42%	81.4°
2047-04-18 Thu	0	—	unknown	—	89.8° 12:20	7.12	32%	70.5°
2047-04-19 Fri	0	—	unknown	—	89.6° 12:15	7.07	23%	60.0°
2047-04-20 Sat	0	—	unknown	—	89.6° 12:15	7.01	16%	50.1°
2047-04-21 Sun	0	—	unknown	—	89.7° 12:10	6.95	10%	41.2°
2047-04-22 Mon	0	—	unknown	—	89.8° 12:05	6.89	5%	33.9°
2047-04-23 Tue	0	—	unknown	—	89.7° 12:00	6.83	2%	29.3°
2047-04-24 Wed	0	—	unknown	—	89.6° 11:55	6.78	0%	28.7°
2047-04-25 Thu	0	—	unknown	—	89.8° 11:50	6.72	1%	32.3°
2047-04-26 Fri	0	—	unknown	—	89.8° 11:45	6.66	3%	39.1°
2047-04-27 Sat	1	—	unknown	—	89.7° 11:40	6.6	7%	47.6°
2047-04-28 Sun	1	—	unknown	—	89.5° 11:35	6.54	12%	57.3°
2047-04-29 Mon	1	—	unknown	—	89.7° 11:35	6.48	19%	67.6°
2047-04-30 Tue	1	—	unknown	—	89.8° 11:30	6.43	28%	78.4°
2047-05-01 Wed	1	—	unknown	—	89.8° 11:25	6.37	37%	89.6°
2047-05-02 Thu	1	—	unknown	—	89.6° 11:20	6.31	48%	101.0°
2047-05-03 Fri	1	—	unknown	—	89.6° 11:20	6.25	58%	112.6°
2047-05-04 Sat	1	—	unknown	—	89.7° 11:15	6.19	69%	124.3°
2047-05-05 Sun	1	—	unknown	—	89.8° 11:10	6.14	79%	135.4°
2047-05-06 Mon	2	—	unknown	05:00–05:05 (marginal, 0.08 h)	89.8° 11:05	6.08	88%	145.1°
2047-05-07 Tue	2	—	unknown	05:00–05:05 (marginal, 0.08 h)	89.6° 11:00	6.02	95%	151.0°
2047-05-08 Wed	2	—	unknown	—	89.6° 11:00	5.97	99%	150.4°
2047-05-09 Thu	2	—	unknown	—	89.8° 10:55	5.91	100%	143.4°
2047-05-10 Fri	2	—	unknown	04:55–05:00 (marginal, 0.08 h)	89.8° 10:50	5.85	98%	133.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-04-11&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.