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: 09-01 (100), 09-02 (100), 09-13 (100), 09-14 (100), 09-15 (100) — by astronomy; check the weather when the night is within four days.

2036-09-01astronomy score per night — click a bar for that night2036-09-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-09-01 Mon	100	—	unknown	21:45–05:15 (good, 7.5 h)	89.7° 03:20	7.64	87%	88.8°
2036-09-02 Tue	100	—	unknown	22:45–05:15 (good, 6.5 h)	89.8° 03:15	7.7	93%	79.6°
2036-09-03 Wed	75	—	unknown	00:10–05:15 (good, 5.08 h)	89.7° 03:10	7.75	97%	70.5°
2036-09-04 Thu	66	—	unknown	03:40–05:15 (good, 1.58 h)	89.6° 03:05	7.81	99%	61.7°
2036-09-05 Fri	58	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.6° 03:05	7.86	100%	53.6°
2036-09-06 Sat	50	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.7° 03:00	7.92	99%	46.5°
2036-09-07 Sun	48	—	unknown	21:20–05:20 (marginal, 8.0 h)	89.8° 02:55	7.97	96%	41.2°
2036-09-08 Mon	80	—	unknown	21:20–21:25 (good, 0.08 h)	89.7° 02:50	8.03	91%	38.4°
2036-09-09 Tue	84	—	unknown	21:20–21:55 (good, 0.58 h)	89.5° 02:45	8.08	84%	39.0°
2036-09-10 Wed	88	—	unknown	21:15–01:10 (good, 3.92 h)	89.6° 02:45	8.14	76%	42.9°
2036-09-11 Thu	92	—	unknown	21:15–04:25 (good, 7.17 h)	89.8° 02:40	8.19	66%	49.5°
2036-09-12 Fri	98	—	unknown	21:10–05:25 (good, 8.25 h)	89.8° 02:35	8.24	56%	58.0°
2036-09-13 Sat	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:30	8.3	44%	67.8°
2036-09-14 Sun	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.5° 02:30	8.35	34%	78.5°
2036-09-15 Mon	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:25	8.4	23%	89.7°
2036-09-16 Tue	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.8° 02:20	8.45	14%	101.1°
2036-09-17 Wed	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.7° 02:15	8.51	7%	112.5°
2036-09-18 Thu	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.6° 02:10	8.56	2%	123.1°
2036-09-19 Fri	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.6° 02:10	8.61	0%	132.3°
2036-09-20 Sat	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.7° 02:05	8.66	1%	138.9°
2036-09-21 Sun	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.8° 02:00	8.71	5%	141.7°
2036-09-22 Mon	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.7° 01:55	8.76	11%	140.2°
2036-09-23 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.5° 01:50	8.81	19%	135.1°
2036-09-24 Wed	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.6° 01:50	8.86	27%	127.8°
2036-09-25 Thu	100	—	unknown	20:50–05:45 (good, 8.92 h)	89.8° 01:45	8.91	37%	119.3°
2036-09-26 Fri	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:40	8.96	47%	110.2°
2036-09-27 Sat	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.6° 01:35	9.01	56%	101.0°
2036-09-28 Sun	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.5° 01:35	9.06	66%	91.6°
2036-09-29 Mon	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.7° 01:30	9.11	74%	82.3°
2036-09-30 Tue	100	—	unknown	20:45–05:50 (good, 9.08 h)	89.8° 01:25	9.16	82%	73.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-09-01&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.