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: 10-22 (100), 10-23 (100), 10-24 (100), 10-25 (100), 10-26 (100) — by astronomy; check the weather when the night is within four days.

2038-10-20astronomy score per night — click a bar for that night2038-11-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-10-20 Wed	87	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:10	10.04	54%	52.8°
2038-10-21 Thu	96	—	unknown	22:00–06:10 (good, 8.17 h)	72.5° 03:10	10.08	44%	65.5°
2038-10-22 Fri	100	—	unknown	22:00–06:10 (good, 8.17 h)	72.5° 03:05	10.12	34%	78.5°
2038-10-23 Sat	100	—	unknown	21:55–06:15 (good, 8.33 h)	72.5° 03:00	10.16	24%	92.1°
2038-10-24 Sun	100	—	unknown	21:50–06:15 (good, 8.42 h)	72.5° 02:55	10.2	15%	106.0°
2038-10-25 Mon	100	—	unknown	21:45–06:15 (good, 8.5 h)	72.5° 02:50	10.24	8%	120.5°
2038-10-26 Tue	100	—	unknown	21:40–06:15 (good, 8.58 h)	72.5° 02:50	10.28	3%	135.2°
2038-10-27 Wed	100	—	unknown	21:40–06:15 (good, 8.58 h)	72.5° 02:45	10.32	0%	150.1°
2038-10-28 Thu	100	—	unknown	21:35–06:20 (good, 8.75 h)	72.5° 02:40	10.36	1%	164.5°
2038-10-29 Fri	100	—	unknown	21:30–06:20 (good, 8.83 h)	72.5° 02:35	10.39	5%	173.0°
2038-10-30 Sat	100	—	unknown	21:25–05:20 (good, 8.92 h)	72.5° 02:30	10.43	11%	162.4°
2038-10-31 Sun	100	—	unknown	20:20–05:20 (good, 9.0 h)	72.5° 01:30	10.47	20%	148.5°
2038-11-01 Mon	100	—	unknown	20:20–05:20 (good, 9.0 h)	72.5° 01:25	10.5	29%	134.6°
2038-11-02 Tue	100	—	unknown	20:20–05:25 (good, 9.08 h)	72.5° 01:20	10.54	40%	121.1°
2038-11-03 Wed	100	—	unknown	20:20–05:25 (good, 9.08 h)	72.5° 01:15	10.58	50%	108.0°
2038-11-04 Thu	100	—	unknown	20:20–05:25 (good, 9.08 h)	72.5° 01:15	10.61	60%	95.2°
2038-11-05 Fri	100	—	unknown	20:25–05:25 (good, 9.0 h)	72.5° 01:10	10.65	70%	82.8°
2038-11-06 Sat	100	—	unknown	21:35–05:30 (good, 7.92 h)	72.5° 01:05	10.68	79%	70.6°
2038-11-07 Sun	97	—	unknown	23:45–05:30 (good, 5.75 h)	72.5° 01:00	10.71	86%	58.6°
2038-11-08 Mon	90	—	unknown	02:45–05:30 (good, 2.75 h)	72.5° 00:55	10.75	92%	46.8°
2038-11-09 Tue	82	—	unknown	05:15–05:30 (good, 0.25 h)	72.5° 00:55	10.78	96%	35.1°
2038-11-10 Wed	37	—	unknown	01:15–05:30 (marginal, 4.25 h)	72.5° 00:50	10.81	99%	23.6°
2038-11-11 Thu	29	—	unknown	02:35–05:35 (marginal, 3.0 h)	72.5° 00:45	10.84	100%	12.8°
2038-11-12 Fri	27	—	unknown	19:40–22:05 (marginal, 2.42 h)	72.5° 00:40	10.87	99%	6.9°
2038-11-13 Sat	32	—	unknown	19:25–23:25 (marginal, 4.0 h)	72.5° 00:35	10.9	96%	14.6°
2038-11-14 Sun	41	—	unknown	19:10–01:05 (marginal, 5.92 h)	72.5° 00:35	10.93	92%	25.8°
2038-11-15 Mon	70	—	unknown	19:25–19:40 (good, 0.25 h)	72.5° 00:30	10.96	86%	37.5°
2038-11-16 Tue	85	—	unknown	19:20–23:40 (good, 4.33 h)	72.5° 00:25	10.99	79%	49.6°
2038-11-17 Wed	93	—	unknown	19:15–03:00 (good, 7.75 h)	72.5° 00:20	11.02	70%	62.0°
2038-11-18 Thu	100	—	unknown	19:10–04:40 (good, 9.5 h)	72.5° 00:20	11.04	60%	74.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-10-20&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.