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: 09-12 (100), 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100) — by astronomy; check the weather when the night is within four days.

2028-09-06astronomy score per night — click a bar for that night2028-10-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2028-09-09 Sat	84	—	unknown	21:20–00:55 (good, 3.58 h)	89.5° 02:45	8.08	71%	37.4°
2028-09-10 Sun	90	—	unknown	21:15–04:50 (good, 7.58 h)	89.6° 02:45	8.13	61%	46.1°
2028-09-11 Mon	95	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:40	8.19	51%	56.2°
2028-09-12 Tue	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:35	8.24	41%	67.3°
2028-09-13 Wed	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:30	8.29	30%	79.1°
2028-09-14 Thu	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.5° 02:30	8.35	20%	91.4°
2028-09-15 Fri	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.6° 02:25	8.4	12%	104.1°
2028-09-16 Sat	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:20	8.45	5%	116.9°
2028-09-17 Sun	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.7° 02:15	8.5	1%	129.4°
2028-09-18 Mon	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.6° 02:10	8.56	0%	140.6°
2028-09-19 Tue	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.5° 02:10	8.61	2%	148.9°
2028-09-20 Wed	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.7° 02:05	8.66	7%	151.6°
2028-09-21 Thu	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.7° 02:00	8.71	14%	147.7°
2028-09-22 Fri	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.7° 01:55	8.76	23%	139.4°
2028-09-23 Sat	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.5° 01:50	8.81	33%	129.2°
2028-09-24 Sun	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.6° 01:50	8.86	44%	118.3°
2028-09-25 Mon	100	—	unknown	20:50–05:45 (good, 8.92 h)	89.7° 01:45	8.91	54%	107.3°
2028-09-26 Tue	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:40	8.96	64%	96.3°
2028-09-27 Wed	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.6° 01:35	9.01	73%	85.6°
2028-09-28 Thu	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.5° 01:30	9.06	81%	75.0°
2028-09-29 Fri	100	—	unknown	22:35–05:45 (good, 7.17 h)	89.6° 01:30	9.11	88%	64.8°
2028-09-30 Sat	93	—	unknown	02:50–05:50 (good, 3.0 h)	89.7° 01:25	9.16	93%	54.9°
2028-10-01 Sun	57	—	unknown	20:35–05:50 (marginal, 9.25 h)	89.7° 01:20	9.2	97%	45.6°
2028-10-02 Mon	46	—	unknown	20:35–05:50 (marginal, 9.25 h)	89.6° 01:15	9.25	99%	37.4°
2028-10-03 Tue	32	—	unknown	20:35–23:30 (marginal, 2.92 h)	89.5° 01:15	9.3	100%	31.2°
2028-10-04 Wed	34	—	unknown	20:30–23:50 (marginal, 3.33 h)	89.7° 01:10	9.35	98%	28.5°
2028-10-05 Thu	40	—	unknown	20:30–00:50 (marginal, 4.33 h)	89.7° 01:05	9.39	95%	30.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-09-06&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.