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 Seven Sisters: 10-13 (100), 10-14 (100), 10-15 (100), 10-16 (100), 10-17 (100) — by astronomy; check the weather when the night is within four days.

2040-10-13astronomy score per night — click a bar for that night2040-11-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-10-13 Sat	100	—	unknown	22:35–06:05 (good, 7.5 h)	72.5° 03:35	9.76	56%	121.4°
2040-10-14 Sun	100	—	unknown	22:40–06:05 (good, 7.42 h)	72.5° 03:35	9.8	68%	107.2°
2040-10-15 Mon	100	—	unknown	22:45–06:05 (good, 7.33 h)	72.5° 03:30	9.85	78%	93.0°
2040-10-16 Tue	100	—	unknown	23:35–06:05 (good, 6.5 h)	72.5° 03:25	9.89	87%	78.8°
2040-10-17 Wed	100	—	unknown	01:40–06:05 (good, 4.42 h)	72.5° 03:20	9.93	93%	64.6°
2040-10-18 Thu	62	—	unknown	05:05–06:10 (good, 1.08 h)	72.5° 03:15	9.98	98%	50.6°
2040-10-19 Fri	38	—	unknown	00:10–06:10 (marginal, 6.0 h)	72.5° 03:15	10.02	100%	36.8°
2040-10-20 Sat	25	—	unknown	04:00–06:10 (marginal, 2.17 h)	72.5° 03:10	10.06	99%	23.3°
2040-10-21 Sun	22	—	unknown	04:40–06:10 (marginal, 1.5 h)	72.5° 03:05	10.1	97%	10.4°
2040-10-22 Mon	27	—	unknown	21:55–02:10 (marginal, 4.25 h)	72.5° 03:00	10.14	92%	4.8°
2040-10-23 Tue	38	—	unknown	21:40–06:15 (marginal, 8.58 h)	72.5° 03:00	10.18	86%	16.2°
2040-10-24 Wed	51	—	unknown	21:25–06:15 (marginal, 8.83 h)	72.5° 02:55	10.22	78%	28.3°
2040-10-25 Thu	74	—	unknown	22:25–01:35 (good, 3.17 h)	72.5° 02:50	10.26	69%	40.4°
2040-10-26 Fri	86	—	unknown	21:40–05:25 (good, 7.75 h)	72.5° 02:45	10.3	60%	52.2°
2040-10-27 Sat	94	—	unknown	21:35–05:20 (good, 8.75 h)	72.5° 02:40	10.34	51%	64.0°
2040-10-28 Sun	100	—	unknown	20:30–05:20 (good, 8.83 h)	72.5° 01:40	10.38	42%	75.9°
2040-10-29 Mon	100	—	unknown	20:30–05:20 (good, 8.83 h)	72.5° 01:35	10.41	32%	87.8°
2040-10-30 Tue	100	—	unknown	20:25–05:20 (good, 8.92 h)	72.5° 01:30	10.45	24%	99.8°
2040-10-31 Wed	100	—	unknown	20:20–05:20 (good, 9.0 h)	72.5° 01:25	10.49	16%	112.1°
2040-11-01 Thu	100	—	unknown	20:15–05:25 (good, 9.17 h)	72.5° 01:20	10.52	9%	124.7°
2040-11-02 Fri	100	—	unknown	20:15–05:25 (good, 9.17 h)	72.5° 01:20	10.56	4%	137.6°
2040-11-03 Sat	100	—	unknown	20:10–05:25 (good, 9.25 h)	72.5° 01:15	10.59	1%	150.8°
2040-11-04 Sun	100	—	unknown	20:05–05:25 (good, 9.33 h)	72.5° 01:10	10.63	0%	164.2°
2040-11-05 Mon	100	—	unknown	20:00–05:25 (good, 9.42 h)	72.5° 01:05	10.66	2%	176.1°
2040-11-06 Tue	100	—	unknown	19:55–05:30 (good, 9.58 h)	72.5° 01:05	10.7	6%	166.9°
2040-11-07 Wed	100	—	unknown	19:55–05:30 (good, 9.58 h)	72.5° 01:00	10.73	12%	153.0°
2040-11-08 Thu	100	—	unknown	19:50–05:30 (good, 9.67 h)	72.5° 00:55	10.76	21%	138.8°
2040-11-09 Fri	100	—	unknown	19:50–05:30 (good, 9.67 h)	72.5° 00:50	10.8	31%	124.6°
2040-11-10 Sat	100	—	unknown	19:45–05:35 (good, 9.83 h)	72.5° 00:45	10.83	42%	110.4°
2040-11-11 Sun	100	—	unknown	19:50–05:35 (good, 9.75 h)	72.5° 00:45	10.86	53%	96.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-10-13&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.