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: 12-27 (100), 12-28 (100), 12-29 (100), 12-30 (100), 12-31 (100) — by astronomy; check the weather when the night is within four days.

2038-12-27astronomy score per night — click a bar for that night2039-01-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2039-01-12 Wed	100	—	unknown	18:55–23:45 (good, 4.83 h)	72.5° 20:40	11.29	94%	81.5°
2039-01-13 Thu	100	—	unknown	18:55–01:10 (good, 6.25 h)	72.5° 20:35	11.27	88%	94.6°
2039-01-14 Fri	100	—	unknown	18:55–01:30 (good, 6.58 h)	72.5° 20:35	11.25	80%	108.0°
2039-01-15 Sat	100	—	unknown	18:55–01:35 (good, 6.67 h)	72.5° 20:30	11.23	70%	121.4°
2039-01-16 Sun	100	—	unknown	18:55–01:30 (good, 6.58 h)	72.5° 20:25	11.21	59%	135.1°
2039-01-17 Mon	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:20	11.18	48%	148.8°
2039-01-18 Tue	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:20	11.16	37%	162.3°
2039-01-19 Wed	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.14	26%	172.9°
2039-01-20 Thu	100	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.11	17%	166.0°
2039-01-21 Fri	100	—	unknown	19:00–01:15 (good, 6.25 h)	72.5° 20:05	11.09	9%	152.5°
2039-01-22 Sat	100	—	unknown	19:05–01:15 (good, 6.17 h)	72.5° 20:00	11.06	4%	138.4°
2039-01-23 Sun	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 20:00	11.03	1%	124.3°
2039-01-24 Mon	100	—	unknown	19:05–01:05 (good, 6.0 h)	72.5° 19:55	11.01	0%	110.3°
2039-01-25 Tue	100	—	unknown	19:05–01:00 (good, 5.92 h)	72.5° 19:50	10.98	2%	96.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-27&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.