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: 12-16 (100), 12-17 (100), 12-18 (100), 12-19 (100), 12-20 (100) — by astronomy; check the weather when the night is within four days.

2038-12-13astronomy score per night — click a bar for that night2039-01-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-13 Mon	56	—	unknown	18:35–03:25 (marginal, 8.83 h)	72.5° 22:40	11.48	96%	46.8°
2038-12-14 Tue	90	—	unknown	18:35–22:15 (good, 3.67 h)	72.5° 22:35	11.49	90%	59.1°
2038-12-15 Wed	98	—	unknown	18:35–01:10 (good, 6.58 h)	72.5° 22:30	11.49	84%	71.7°
2038-12-16 Thu	100	—	unknown	18:35–02:45 (good, 8.17 h)	72.5° 22:25	11.5	75%	84.5°
2038-12-17 Fri	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.5° 22:25	11.5	66%	97.5°
2038-12-18 Sat	100	—	unknown	18:35–03:20 (good, 8.75 h)	72.5° 22:20	11.5	55%	110.9°
2038-12-19 Sun	100	—	unknown	18:35–03:20 (good, 8.75 h)	72.5° 22:15	11.51	44%	124.5°
2038-12-20 Mon	100	—	unknown	18:35–03:20 (good, 8.75 h)	72.5° 22:10	11.51	33%	138.3°
2038-12-21 Tue	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.5° 22:10	11.51	23%	152.4°
2038-12-22 Wed	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.5° 22:05	11.51	14%	166.1°
2038-12-23 Thu	100	—	unknown	18:40–03:10 (good, 8.5 h)	72.5° 22:00	11.51	6%	172.6°
2038-12-24 Fri	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.5° 21:55	11.5	2%	161.1°
2038-12-25 Sat	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.5° 21:50	11.5	0%	146.9°
2038-12-26 Sun	100	—	unknown	18:40–03:00 (good, 8.33 h)	72.5° 21:50	11.5	1%	132.5°
2038-12-27 Mon	100	—	unknown	18:40–02:55 (good, 8.25 h)	72.5° 21:45	11.49	5%	118.3°
2038-12-28 Tue	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.5° 21:40	11.48	11%	104.5°
2038-12-29 Wed	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.5° 21:35	11.48	18%	91.1°
2038-12-30 Thu	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.5° 21:30	11.47	27%	78.2°
2038-12-31 Fri	100	—	unknown	18:45–02:40 (good, 7.92 h)	72.5° 21:30	11.46	37%	65.6°
2039-01-01 Sat	96	—	unknown	18:45–02:35 (good, 7.83 h)	72.5° 21:25	11.45	46%	53.5°
2039-01-02 Sun	88	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:20	11.44	56%	41.6°
2039-01-03 Mon	79	—	unknown	22:55–01:35 (good, 2.67 h)	72.5° 21:15	11.43	65%	29.9°
2039-01-04 Tue	52	—	unknown	18:45–02:45 (marginal, 8.0 h)	72.5° 21:15	11.42	74%	18.6°
2039-01-05 Wed	37	—	unknown	18:45–02:30 (marginal, 7.75 h)	72.5° 21:10	11.4	82%	8.8°
2039-01-06 Thu	26	—	unknown	18:50–02:10 (marginal, 7.33 h)	72.5° 21:05	11.39	88%	9.3°
2039-01-07 Fri	22	—	unknown	18:50–20:35 (marginal, 1.75 h)	72.5° 21:00	11.38	94%	19.6°
2039-01-08 Sat	22	—	unknown	18:50–20:45 (marginal, 1.92 h)	72.5° 20:55	11.36	98%	31.3°
2039-01-09 Sun	34	—	unknown	18:50–23:35 (marginal, 4.75 h)	72.5° 20:55	11.34	100%	43.4°
2039-01-10 Mon	53	—	unknown	18:50–19:00 (good, 0.17 h)	72.5° 20:50	11.33	100%	55.9°
2039-01-11 Tue	72	—	unknown	18:50–21:30 (good, 2.67 h)	72.5° 20:45	11.31	98%	68.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-13&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.