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), 09-02 (100), 09-03 (100), 09-04 (100) — by astronomy; check the weather when the night is within four days.

2029-08-20astronomy score per night — click a bar for that night2029-09-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-08-20 Mon	100	—	unknown	22:30–04:55 (good, 6.42 h)	89.6° 04:05	6.95	90%	95.2°
2029-08-21 Tue	100	—	unknown	23:20–04:55 (good, 5.58 h)	89.5° 04:05	7.0	95%	83.7°
2029-08-22 Wed	72	—	unknown	01:00–05:00 (good, 4.0 h)	89.7° 04:00	7.06	98%	72.4°
2029-08-23 Thu	62	—	unknown	04:35–05:00 (good, 0.42 h)	89.7° 03:55	7.12	100%	61.6°
2029-08-24 Fri	46	—	unknown	21:50–05:00 (marginal, 7.17 h)	89.7° 03:50	7.17	99%	51.4°
2029-08-25 Sat	35	—	unknown	21:50–05:05 (marginal, 7.25 h)	89.5° 03:45	7.23	96%	42.2°
2029-08-26 Sun	35	—	unknown	21:45–05:05 (marginal, 7.33 h)	89.6° 03:45	7.29	92%	34.6°
2029-08-27 Mon	39	—	unknown	21:45–05:05 (marginal, 7.33 h)	89.7° 03:40	7.35	86%	29.8°
2029-08-28 Tue	51	—	unknown	21:30–05:05 (marginal, 7.58 h)	89.7° 03:35	7.4	79%	29.0°
2029-08-29 Wed	81	—	unknown	21:40–22:15 (good, 0.58 h)	89.6° 03:30	7.46	71%	32.3°
2029-08-30 Thu	85	—	unknown	21:40–03:25 (good, 5.75 h)	89.5° 03:30	7.51	62%	38.8°
2029-08-31 Fri	91	—	unknown	21:35–05:10 (good, 7.58 h)	89.6° 03:25	7.57	52%	47.3°
2029-09-01 Sat	97	—	unknown	21:35–05:10 (good, 7.58 h)	89.7° 03:20	7.63	43%	56.9°
2029-09-02 Sun	100	—	unknown	21:35–05:15 (good, 7.67 h)	89.7° 03:15	7.68	33%	67.3°
2029-09-03 Mon	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.6° 03:10	7.74	24%	78.3°
2029-09-04 Tue	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.5° 03:10	7.79	16%	89.9°
2029-09-05 Wed	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 03:05	7.85	8%	101.8°
2029-09-06 Thu	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 03:00	7.9	3%	113.9°
2029-09-07 Fri	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 02:55	7.96	0%	125.9°
2029-09-08 Sat	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.5° 02:50	8.01	0%	137.1°
2029-09-09 Sun	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.6° 02:50	8.07	3%	146.2°
2029-09-10 Mon	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:45	8.12	9%	151.0°
2029-09-11 Tue	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:40	8.17	17%	149.2°
2029-09-12 Wed	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.6° 02:35	8.23	27%	142.0°
2029-09-13 Thu	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.5° 02:30	8.28	37%	132.0°
2029-09-14 Fri	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:30	8.33	48%	120.9°
2029-09-15 Sat	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:25	8.39	60%	109.4°
2029-09-16 Sun	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:20	8.44	70%	97.8°
2029-09-17 Mon	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.6° 02:15	8.49	79%	86.4°
2029-09-18 Tue	100	—	unknown	21:55–05:35 (good, 7.67 h)	89.5° 02:15	8.54	86%	75.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-08-20&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.