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: 08-01 (100), 08-14 (100), 08-15 (100), 08-16 (100), 08-17 (100) — by astronomy; check the weather when the night is within four days.

2039-08-01astronomy score per night — click a bar for that night2039-08-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-08-01 Mon	100	—	unknown	23:35–04:25 (good, 4.83 h)	89.7° 05:25	5.84	92%	109.1°
2039-08-02 Tue	84	—	unknown	23:40–04:25 (good, 4.75 h)	89.8° 05:20	5.89	97%	97.6°
2039-08-03 Wed	76	—	unknown	00:15–04:30 (good, 4.25 h)	89.7° 05:15	5.95	100%	86.0°
2039-08-04 Thu	63	—	unknown	01:30–04:30 (good, 3.0 h)	89.6° 05:10	6.01	100%	74.7°
2039-08-05 Fri	52	—	unknown	22:35–04:30 (marginal, 5.92 h)	89.6° 05:10	6.06	97%	64.0°
2039-08-06 Sat	46	—	unknown	22:30–04:35 (marginal, 6.08 h)	89.7° 05:05	6.12	92%	54.3°
2039-08-07 Sun	46	—	unknown	22:25–04:35 (marginal, 6.17 h)	89.8° 05:00	6.18	85%	46.2°
2039-08-08 Mon	64	—	unknown	22:50–23:10 (good, 0.33 h)	89.7° 04:55	6.23	77%	40.4°
2039-08-09 Tue	81	—	unknown	22:50–02:50 (good, 4.0 h)	89.5° 04:50	6.29	68%	37.5°
2039-08-10 Wed	85	—	unknown	22:45–04:40 (good, 5.92 h)	89.6° 04:50	6.35	58%	38.1°
2039-08-11 Thu	88	—	unknown	22:40–04:40 (good, 6.0 h)	89.8° 04:45	6.4	49%	41.7°
2039-08-12 Fri	92	—	unknown	22:35–04:45 (good, 6.17 h)	89.8° 04:40	6.46	40%	47.6°
2039-08-13 Sat	96	—	unknown	22:35–04:45 (good, 6.17 h)	89.6° 04:35	6.52	30%	55.1°
2039-08-14 Sun	100	—	unknown	22:30–04:45 (good, 6.25 h)	89.5° 04:35	6.58	22%	63.5°
2039-08-15 Mon	100	—	unknown	22:25–04:45 (good, 6.33 h)	89.7° 04:30	6.63	15%	72.5°
2039-08-16 Tue	100	—	unknown	22:20–04:50 (good, 6.5 h)	89.8° 04:25	6.69	9%	82.0°
2039-08-17 Wed	100	—	unknown	22:15–04:50 (good, 6.58 h)	89.7° 04:20	6.75	4%	91.8°
2039-08-18 Thu	100	—	unknown	22:15–04:50 (good, 6.58 h)	89.6° 04:15	6.81	1%	101.7°
2039-08-19 Fri	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.6° 04:15	6.86	0%	111.6°
2039-08-20 Sat	100	—	unknown	22:05–04:55 (good, 6.83 h)	89.7° 04:10	6.92	1%	121.2°
2039-08-21 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	89.8° 04:05	6.98	5%	130.0°
2039-08-22 Mon	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.7° 04:00	7.04	11%	137.3°
2039-08-23 Tue	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.5° 03:55	7.09	18%	141.9°
2039-08-24 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.6° 03:55	7.15	28%	142.5°
2039-08-25 Thu	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.8° 03:50	7.21	38%	138.9°
2039-08-26 Fri	100	—	unknown	21:50–05:05 (good, 7.25 h)	89.8° 03:45	7.26	50%	132.0°
2039-08-27 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:40	7.32	61%	122.9°
2039-08-28 Sun	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.5° 03:40	7.38	72%	112.5°
2039-08-29 Mon	100	—	unknown	21:50–05:10 (good, 7.33 h)	89.7° 03:35	7.43	82%	101.4°
2039-08-30 Tue	100	—	unknown	21:55–05:10 (good, 7.25 h)	89.8° 03:30	7.49	90%	90.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-08-01&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.