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: 07-31 (100), 08-01 (100), 08-02 (100), 08-03 (100), 08-04 (100) — by astronomy; check the weather when the night is within four days.

2035-07-27astronomy score per night — click a bar for that night2035-08-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-07-27 Fri	81	—	unknown	23:40–04:15 (good, 4.58 h)	89.6° 05:45	5.57	52%	38.0°
2035-07-28 Sat	88	—	unknown	23:35–04:20 (good, 4.75 h)	89.7° 05:40	5.62	41%	42.0°
2035-07-29 Sun	93	—	unknown	23:30–04:20 (good, 4.83 h)	89.8° 05:35	5.67	30%	49.4°
2035-07-30 Mon	99	—	unknown	23:30–04:20 (good, 4.83 h)	89.6° 05:30	5.73	20%	58.9°
2035-07-31 Tue	100	—	unknown	23:25–04:25 (good, 5.0 h)	89.5° 05:30	5.78	11%	69.7°
2035-08-01 Wed	100	—	unknown	23:20–04:25 (good, 5.08 h)	89.7° 05:25	5.84	5%	81.3°
2035-08-02 Thu	100	—	unknown	23:15–04:25 (good, 5.17 h)	89.8° 05:20	5.89	1%	93.2°
2035-08-03 Fri	100	—	unknown	23:10–04:30 (good, 5.33 h)	89.7° 05:15	5.95	0%	104.9°
2035-08-04 Sat	100	—	unknown	23:10–04:30 (good, 5.33 h)	89.6° 05:10	6.0	2%	116.0°
2035-08-05 Sun	100	—	unknown	23:05–04:30 (good, 5.42 h)	89.5° 05:10	6.06	7%	126.0°
2035-08-06 Mon	100	—	unknown	23:00–04:35 (good, 5.58 h)	89.7° 05:05	6.12	13%	134.3°
2035-08-07 Tue	100	—	unknown	22:55–04:35 (good, 5.67 h)	89.8° 05:00	6.17	22%	140.1°
2035-08-08 Wed	100	—	unknown	22:55–04:35 (good, 5.67 h)	89.7° 04:55	6.23	31%	142.5°
2035-08-09 Thu	100	—	unknown	22:50–04:40 (good, 5.83 h)	89.5° 04:50	6.29	40%	141.3°
2035-08-10 Fri	100	—	unknown	22:50–04:40 (good, 5.83 h)	89.6° 04:50	6.34	50%	137.0°
2035-08-11 Sat	100	—	unknown	22:45–04:40 (good, 5.92 h)	89.7° 04:45	6.4	60%	130.6°
2035-08-12 Sun	100	—	unknown	22:45–04:45 (good, 6.0 h)	89.8° 04:40	6.46	69%	122.8°
2035-08-13 Mon	100	—	unknown	22:45–04:45 (good, 6.0 h)	89.6° 04:35	6.52	77%	114.3°
2035-08-14 Tue	100	—	unknown	22:50–04:45 (good, 5.92 h)	89.5° 04:35	6.57	85%	105.3°
2035-08-15 Wed	100	—	unknown	22:50–04:45 (good, 5.92 h)	89.7° 04:30	6.63	91%	96.0°
2035-08-16 Thu	100	—	unknown	23:30–04:50 (good, 5.33 h)	89.8° 04:25	6.69	96%	86.4°
2035-08-17 Fri	73	—	unknown	00:40–04:50 (good, 4.17 h)	89.7° 04:20	6.75	99%	76.8°
2035-08-18 Sat	65	—	unknown	03:10–04:50 (good, 1.67 h)	89.6° 04:15	6.8	100%	67.4°
2035-08-19 Sun	53	—	unknown	22:00–04:55 (marginal, 6.92 h)	89.5° 04:15	6.86	99%	58.2°
2035-08-20 Mon	44	—	unknown	22:00–04:55 (marginal, 6.92 h)	89.7° 04:10	6.92	96%	49.9°
2035-08-21 Tue	44	—	unknown	22:00–04:55 (marginal, 6.92 h)	89.8° 04:05	6.98	91%	42.9°
2035-08-22 Wed	67	—	unknown	21:55–22:15 (good, 0.33 h)	89.7° 04:00	7.03	85%	38.5°
2035-08-23 Thu	82	—	unknown	21:55–22:45 (good, 0.83 h)	89.5° 03:55	7.09	76%	37.6°
2035-08-24 Fri	86	—	unknown	21:50–03:20 (good, 5.5 h)	89.6° 03:55	7.15	66%	40.8°
2035-08-25 Sat	91	—	unknown	21:50–05:00 (good, 7.17 h)	89.7° 03:50	7.21	55%	47.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-07-27&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.