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: 03-13 (5), 03-14 (3), 03-15 (2), 03-16 (2), 03-17 (1) — by astronomy; check the weather when the night is within four days.

2035-03-13astronomy score per night — click a bar for that night2035-04-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-03-13 Tue	5	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.6° 13:40	9.09	19%	41.1°
2035-03-14 Wed	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.6° 13:40	9.04	29%	48.4°
2035-03-15 Thu	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.7° 13:35	8.99	40%	57.7°
2035-03-16 Fri	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.8° 13:30	8.94	51%	68.1°
2035-03-17 Sat	1	—	unknown	—	89.7° 13:25	8.88	62%	79.1°
2035-03-18 Sun	1	—	unknown	—	89.5° 13:20	8.83	73%	90.2°
2035-03-19 Mon	1	—	unknown	—	89.6° 13:20	8.78	82%	101.3°
2035-03-20 Tue	1	—	unknown	—	89.7° 13:15	8.73	90%	112.0°
2035-03-21 Wed	0	—	unknown	—	89.8° 13:10	8.68	96%	122.0°
2035-03-22 Thu	0	—	unknown	—	89.6° 13:05	8.63	99%	130.8°
2035-03-23 Fri	0	—	unknown	—	89.5° 13:05	8.58	100%	137.9°
2035-03-24 Sat	0	—	unknown	—	89.7° 13:00	8.52	99%	142.2°
2035-03-25 Sun	0	—	unknown	—	89.8° 13:55	8.47	96%	143.0°
2035-03-26 Mon	0	—	unknown	—	89.7° 13:50	8.42	91%	140.3°
2035-03-27 Tue	0	—	unknown	—	89.6° 13:45	8.36	85%	135.0°
2035-03-28 Wed	0	—	unknown	—	89.6° 13:45	8.31	77%	127.8°
2035-03-29 Thu	0	—	unknown	—	89.7° 13:40	8.26	69%	119.6°
2035-03-30 Fri	0	—	unknown	—	89.8° 13:35	8.2	60%	110.8°
2035-03-31 Sat	0	—	unknown	—	89.7° 13:30	8.15	50%	101.5°
2035-04-01 Sun	0	—	unknown	—	89.5° 13:25	8.09	41%	92.0°
2035-04-02 Mon	0	—	unknown	—	89.6° 13:25	8.04	31%	82.3°
2035-04-03 Tue	0	—	unknown	—	89.7° 13:20	7.98	22%	72.4°
2035-04-04 Wed	0	—	unknown	—	89.8° 13:15	7.93	14%	62.7°
2035-04-05 Thu	0	—	unknown	—	89.6° 13:10	7.87	8%	53.3°
2035-04-06 Fri	0	—	unknown	—	89.5° 13:10	7.82	3%	45.1°
2035-04-07 Sat	0	—	unknown	—	89.7° 13:05	7.76	0%	39.1°
2035-04-08 Sun	0	—	unknown	—	89.8° 13:00	7.7	0%	36.9°
2035-04-09 Mon	0	—	unknown	—	89.7° 12:55	7.65	3%	39.3°
2035-04-10 Tue	0	—	unknown	—	89.6° 12:50	7.59	8%	45.8°
2035-04-11 Wed	0	—	unknown	—	89.5° 12:50	7.53	16%	54.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-03-13&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.