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: 10-18 (100), 10-19 (100), 10-20 (100), 10-21 (100), 10-22 (100) — by astronomy; check the weather when the night is within four days.

2041-10-18astronomy score per night — click a bar for that night2041-11-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-10-18 Fri	100	—	unknown	22:15–06:10 (good, 7.92 h)	72.5° 03:20	9.97	31%	78.5°
2041-10-19 Sat	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.5° 03:15	10.01	22%	90.3°
2041-10-20 Sun	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:10	10.05	15%	102.1°
2041-10-21 Mon	100	—	unknown	22:00–06:10 (good, 8.17 h)	72.5° 03:05	10.09	9%	114.0°
2041-10-22 Tue	100	—	unknown	21:55–06:10 (good, 8.25 h)	72.5° 03:05	10.13	4%	125.9°
2041-10-23 Wed	100	—	unknown	21:55–06:15 (good, 8.33 h)	72.5° 03:00	10.17	1%	138.0°
2041-10-24 Thu	100	—	unknown	21:50–06:15 (good, 8.42 h)	72.5° 02:55	10.21	0%	150.2°
2041-10-25 Fri	100	—	unknown	21:45–06:15 (good, 8.5 h)	72.5° 02:50	10.25	1%	162.5°
2041-10-26 Sat	100	—	unknown	21:40–05:15 (good, 8.58 h)	72.5° 02:45	10.29	3%	174.8°
2041-10-27 Sun	100	—	unknown	20:35–05:15 (good, 8.67 h)	72.5° 01:45	10.33	8%	171.7°
2041-10-28 Mon	100	—	unknown	20:35–05:20 (good, 8.75 h)	72.5° 01:40	10.37	15%	158.9°
2041-10-29 Tue	100	—	unknown	20:30–05:20 (good, 8.83 h)	72.5° 01:35	10.4	23%	145.7°
2041-10-30 Wed	100	—	unknown	20:30–05:20 (good, 8.83 h)	72.5° 01:30	10.44	33%	132.3°
2041-10-31 Thu	100	—	unknown	20:25–05:20 (good, 8.92 h)	72.5° 01:25	10.48	44%	118.6°
2041-11-01 Fri	100	—	unknown	20:25–05:25 (good, 9.0 h)	72.5° 01:25	10.51	55%	104.7°
2041-11-02 Sat	100	—	unknown	20:30–05:25 (good, 8.92 h)	72.5° 01:20	10.55	66%	90.6°
2041-11-03 Sun	100	—	unknown	21:10–05:25 (good, 8.25 h)	72.5° 01:15	10.59	76%	76.2°
2041-11-04 Mon	99	—	unknown	23:10–05:25 (good, 6.25 h)	72.5° 01:10	10.62	86%	61.7°
2041-11-05 Tue	89	—	unknown	03:05–05:25 (good, 2.33 h)	72.5° 01:10	10.66	93%	47.0°
2041-11-06 Wed	44	—	unknown	23:50–05:30 (marginal, 5.67 h)	72.5° 01:05	10.69	98%	32.4°
2041-11-07 Thu	30	—	unknown	02:25–05:30 (marginal, 3.08 h)	72.5° 01:00	10.72	100%	17.9°
2041-11-08 Fri	23	—	unknown	04:15–05:30 (marginal, 1.25 h)	72.5° 00:55	10.76	99%	4.1°
2041-11-09 Sat	28	—	unknown	19:45–23:10 (marginal, 3.42 h)	72.5° 00:50	10.79	96%	10.6°
2041-11-10 Sun	39	—	unknown	19:30–01:20 (marginal, 5.83 h)	72.5° 00:50	10.82	91%	24.1°
2041-11-11 Mon	56	—	unknown	19:10–05:35 (marginal, 10.42 h)	72.5° 00:45	10.85	84%	37.3°
2041-11-12 Tue	84	—	unknown	19:35–00:20 (good, 4.75 h)	72.5° 00:40	10.88	76%	50.0°
2041-11-13 Wed	92	—	unknown	19:30–03:35 (good, 8.08 h)	72.5° 00:35	10.91	67%	62.5°
2041-11-14 Thu	100	—	unknown	19:25–05:05 (good, 9.67 h)	72.5° 00:30	10.94	57%	74.6°
2041-11-15 Fri	100	—	unknown	19:25–05:20 (good, 9.92 h)	72.5° 00:30	10.97	48%	86.6°
2041-11-16 Sat	100	—	unknown	19:20–05:25 (good, 10.08 h)	72.5° 00:25	11.0	38%	98.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-10-18&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.