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: 08-16 (100), 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100) — by astronomy; check the weather when the night is within four days.

2028-08-10astronomy score per night — click a bar for that night2028-09-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-08-10 Thu	44	—	unknown	22:15–04:40 (marginal, 6.42 h)	89.7° 04:45	6.38	74%	29.1°
2028-08-11 Fri	64	—	unknown	22:40–22:50 (good, 0.17 h)	89.6° 04:40	6.44	65%	28.5°
2028-08-12 Sat	81	—	unknown	22:35–04:45 (good, 6.17 h)	89.5° 04:35	6.5	56%	32.4°
2028-08-13 Sun	86	—	unknown	22:30–04:45 (good, 6.25 h)	89.6° 04:35	6.56	46%	39.6°
2028-08-14 Mon	91	—	unknown	22:25–04:45 (good, 6.33 h)	89.7° 04:30	6.61	35%	49.0°
2028-08-15 Tue	98	—	unknown	22:20–04:50 (good, 6.5 h)	89.7° 04:25	6.67	26%	59.8°
2028-08-16 Wed	100	—	unknown	22:20–04:50 (good, 6.5 h)	89.6° 04:20	6.73	16%	71.5°
2028-08-17 Thu	100	—	unknown	22:15–04:50 (good, 6.58 h)	89.5° 04:20	6.79	9%	83.9°
2028-08-18 Fri	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.6° 04:15	6.84	3%	96.8°
2028-08-19 Sat	100	—	unknown	22:05–04:55 (good, 6.83 h)	89.7° 04:10	6.9	0%	109.9°
2028-08-20 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	89.7° 04:05	6.96	0%	122.7°
2028-08-21 Mon	100	—	unknown	22:00–04:55 (good, 6.92 h)	89.6° 04:00	7.02	4%	134.7°
2028-08-22 Tue	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.5° 04:00	7.07	9%	144.8°
2028-08-23 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.7° 03:55	7.13	17%	151.0°
2028-08-24 Thu	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.7° 03:50	7.19	27%	151.0°
2028-08-25 Fri	100	—	unknown	21:50–05:05 (good, 7.25 h)	89.7° 03:45	7.25	38%	145.2°
2028-08-26 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.5° 03:40	7.3	49%	136.3°
2028-08-27 Sun	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:40	7.36	59%	126.1°
2028-08-28 Mon	100	—	unknown	21:40–05:05 (good, 7.42 h)	89.7° 03:35	7.42	69%	115.4°
2028-08-29 Tue	100	—	unknown	21:45–05:10 (good, 7.42 h)	89.7° 03:30	7.47	78%	104.5°
2028-08-30 Wed	100	—	unknown	21:50–05:10 (good, 7.33 h)	89.6° 03:25	7.53	86%	93.7°
2028-08-31 Thu	100	—	unknown	22:30–05:10 (good, 6.67 h)	89.5° 03:25	7.58	92%	83.0°
2028-09-01 Fri	100	—	unknown	00:05–05:15 (good, 5.17 h)	89.6° 03:20	7.64	96%	72.5°
2028-09-02 Sat	67	—	unknown	03:35–05:15 (good, 1.67 h)	89.7° 03:15	7.7	99%	62.2°
2028-09-03 Sun	57	—	unknown	21:30–05:15 (marginal, 7.75 h)	89.7° 03:10	7.75	100%	52.4°
2028-09-04 Mon	41	—	unknown	21:30–05:15 (marginal, 7.75 h)	89.6° 03:05	7.81	99%	43.4°
2028-09-05 Tue	35	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.5° 03:05	7.86	96%	35.6°
2028-09-06 Wed	36	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.7° 03:00	7.92	92%	30.1°
2028-09-07 Thu	45	—	unknown	21:20–05:20 (marginal, 8.0 h)	89.7° 02:55	7.97	86%	28.3°
2028-09-08 Fri	80	—	unknown	21:20–21:25 (good, 0.08 h)	89.7° 02:50	8.03	79%	31.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-08-10&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.