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: 10-17 (100), 10-18 (100), 10-19 (100), 10-20 (100), 10-21 (100) — by astronomy; check the weather when the night is within four days.

2031-10-17astronomy score per night — click a bar for that night2031-11-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-10-17 Fri	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.5° 03:25	9.9	3%	163.9°
2031-10-18 Sat	100	—	unknown	22:15–06:05 (good, 7.83 h)	72.5° 03:20	9.94	8%	174.7°
2031-10-19 Sun	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.5° 03:15	9.98	15%	166.6°
2031-10-20 Mon	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:10	10.02	24%	153.0°
2031-10-21 Tue	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:10	10.07	34%	139.1°
2031-10-22 Wed	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:05	10.11	46%	125.0°
2031-10-23 Thu	100	—	unknown	22:05–06:15 (good, 8.17 h)	72.5° 03:00	10.15	57%	110.9°
2031-10-24 Fri	100	—	unknown	22:10–06:15 (good, 8.08 h)	72.5° 02:55	10.19	68%	96.9°
2031-10-25 Sat	100	—	unknown	22:35–05:15 (good, 7.67 h)	72.5° 02:55	10.23	78%	82.9°
2031-10-26 Sun	100	—	unknown	23:15–05:15 (good, 6.0 h)	72.5° 01:50	10.27	87%	69.0°
2031-10-27 Mon	94	—	unknown	02:30–05:15 (good, 2.75 h)	72.5° 01:45	10.31	93%	55.2°
2031-10-28 Tue	54	—	unknown	21:00–05:20 (marginal, 8.33 h)	72.5° 01:40	10.34	98%	41.7°
2031-10-29 Wed	31	—	unknown	02:05–05:20 (marginal, 3.25 h)	72.5° 01:35	10.38	100%	28.4°
2031-10-30 Thu	25	—	unknown	03:10–05:20 (marginal, 2.17 h)	72.5° 01:35	10.42	100%	15.6°
2031-10-31 Fri	24	—	unknown	20:35–22:45 (marginal, 2.17 h)	72.5° 01:30	10.46	97%	5.4°
2031-11-01 Sat	32	—	unknown	20:15–00:55 (marginal, 4.67 h)	72.5° 01:25	10.49	93%	11.9°
2031-11-02 Sun	44	—	unknown	20:00–05:25 (marginal, 9.42 h)	72.5° 01:20	10.53	87%	23.7°
2031-11-03 Mon	76	—	unknown	20:10–20:35 (good, 0.42 h)	72.5° 01:15	10.57	80%	35.6°
2031-11-04 Tue	87	—	unknown	20:10–01:20 (good, 5.17 h)	72.5° 01:15	10.6	72%	47.4°
2031-11-05 Wed	94	—	unknown	20:05–04:20 (good, 8.25 h)	72.5° 01:10	10.64	63%	59.2°
2031-11-06 Thu	100	—	unknown	20:00–05:30 (good, 9.5 h)	72.5° 01:05	10.67	54%	71.0°
2031-11-07 Fri	100	—	unknown	19:55–05:30 (good, 9.58 h)	72.5° 01:00	10.7	44%	82.8°
2031-11-08 Sat	100	—	unknown	19:50–05:30 (good, 9.67 h)	72.5° 01:00	10.74	35%	94.8°
2031-11-09 Sun	100	—	unknown	19:50–05:30 (good, 9.67 h)	72.5° 00:55	10.77	26%	107.0°
2031-11-10 Mon	100	—	unknown	19:45–05:30 (good, 9.75 h)	72.5° 00:50	10.8	17%	119.5°
2031-11-11 Tue	100	—	unknown	19:40–05:35 (good, 9.92 h)	72.5° 00:45	10.83	10%	132.3°
2031-11-12 Wed	100	—	unknown	19:35–05:35 (good, 10.0 h)	72.5° 00:40	10.86	5%	145.5°
2031-11-13 Thu	100	—	unknown	19:30–05:35 (good, 10.08 h)	72.5° 00:40	10.89	1%	158.9°
2031-11-14 Fri	100	—	unknown	19:30–05:35 (good, 10.08 h)	72.5° 00:35	10.92	0%	171.8°
2031-11-15 Sat	100	—	unknown	19:25–05:35 (good, 10.17 h)	72.5° 00:30	10.95	1%	170.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-10-17&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.