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: 08-20 (100), 08-21 (100), 08-22 (100), 08-23 (100), 08-24 (100) — by astronomy; check the weather when the night is within four days.

2045-08-20astronomy score per night — click a bar for that night2045-09-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-08-20 Sun	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.5° 04:05	6.95	64%	127.7°
2045-08-21 Mon	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.6° 04:05	7.01	74%	117.6°
2045-08-22 Tue	100	—	unknown	22:10–05:00 (good, 6.83 h)	89.8° 04:00	7.07	82%	107.2°
2045-08-23 Wed	100	—	unknown	22:15–05:00 (good, 6.75 h)	89.8° 03:55	7.13	88%	96.8°
2045-08-24 Thu	100	—	unknown	22:35–05:00 (good, 6.42 h)	89.7° 03:50	7.18	94%	86.4°
2045-08-25 Fri	76	—	unknown	00:00–05:05 (good, 5.08 h)	89.5° 03:50	7.24	98%	76.0°
2045-08-26 Sat	67	—	unknown	03:05–05:05 (good, 2.0 h)	89.7° 03:45	7.3	100%	65.8°
2045-08-27 Sun	57	—	unknown	21:45–05:05 (marginal, 7.33 h)	89.8° 03:40	7.35	100%	55.9°
2045-08-28 Mon	42	—	unknown	21:45–05:05 (marginal, 7.33 h)	89.8° 03:35	7.41	98%	46.5°
2045-08-29 Tue	36	—	unknown	21:40–05:10 (marginal, 7.5 h)	89.6° 03:30	7.47	95%	38.1°
2045-08-30 Wed	38	—	unknown	21:40–05:10 (marginal, 7.5 h)	89.6° 03:30	7.52	90%	31.6°
2045-08-31 Thu	46	—	unknown	21:35–05:10 (marginal, 7.58 h)	89.7° 03:25	7.58	83%	28.6°
2045-09-01 Fri	80	—	unknown	21:35–21:50 (good, 0.25 h)	89.8° 03:20	7.63	75%	30.3°
2045-09-02 Sat	84	—	unknown	21:35–01:55 (good, 4.33 h)	89.7° 03:15	7.69	66%	36.3°
2045-09-03 Sun	89	—	unknown	21:30–05:15 (good, 7.75 h)	89.6° 03:10	7.74	55%	45.1°
2045-09-04 Mon	95	—	unknown	21:30–05:15 (good, 7.75 h)	89.6° 03:10	7.8	44%	55.6°
2045-09-05 Tue	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.8° 03:05	7.86	34%	67.2°
2045-09-06 Wed	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.8° 03:00	7.91	23%	79.5°
2045-09-07 Thu	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 02:55	7.96	14%	92.3°
2045-09-08 Fri	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.5° 02:55	8.02	7%	105.3°
2045-09-09 Sat	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.7° 02:50	8.07	2%	118.2°
2045-09-10 Sun	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.8° 02:45	8.13	0%	130.5°
2045-09-11 Mon	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.8° 02:40	8.18	1%	141.3°
2045-09-12 Tue	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.6° 02:35	8.23	5%	149.0°
2045-09-13 Wed	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:35	8.29	11%	151.4°
2045-09-14 Thu	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.7° 02:30	8.34	20%	147.7°
2045-09-15 Fri	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.8° 02:25	8.39	29%	140.1°
2045-09-16 Sat	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:20	8.45	39%	130.7°
2045-09-17 Sun	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.6° 02:15	8.5	49%	120.5°
2045-09-18 Mon	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.6° 02:15	8.55	58%	110.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-08-20&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.