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 Triangulum Pinwheel: 12-25 (100), 12-26 (100), 12-27 (100), 12-28 (100), 12-29 (100) — by astronomy; check the weather when the night is within four days.

2026-12-23astronomy score per night — click a bar for that night2027-01-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-12-23 Wed	46	—	unknown	18:40–01:00 (marginal, 6.33 h)	79.1° 19:45	11.51	100%	57.6°
2026-12-24 Thu	70	—	unknown	18:40–21:10 (good, 2.5 h)	79.1° 19:45	11.5	99%	72.3°
2026-12-25 Fri	100	—	unknown	18:40–23:30 (good, 4.83 h)	79.1° 19:40	11.5	95%	87.0°
2026-12-26 Sat	100	—	unknown	18:40–00:45 (good, 6.08 h)	79.1° 19:35	11.5	88%	101.5°
2026-12-27 Sun	100	—	unknown	18:40–00:50 (good, 6.17 h)	79.1° 19:30	11.49	79%	115.5°
2026-12-28 Mon	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.1° 19:30	11.49	70%	129.0°
2026-12-29 Tue	100	—	unknown	18:40–00:50 (good, 6.17 h)	79.1° 19:25	11.48	59%	141.7°
2026-12-30 Wed	100	—	unknown	18:40–00:50 (good, 6.17 h)	79.1° 19:20	11.47	48%	153.3°
2026-12-31 Thu	100	—	unknown	18:45–00:50 (good, 6.08 h)	79.1° 19:15	11.46	38%	162.6°
2027-01-01 Fri	100	—	unknown	18:45–00:45 (good, 6.0 h)	79.1° 19:10	11.45	29%	165.3°
2027-01-02 Sat	100	—	unknown	18:45–00:40 (good, 5.92 h)	79.1° 19:10	11.44	20%	159.4°
2027-01-03 Sun	100	—	unknown	18:45–00:35 (good, 5.83 h)	79.1° 19:05	11.43	13%	149.7°
2027-01-04 Mon	100	—	unknown	18:45–00:30 (good, 5.75 h)	79.1° 19:00	11.42	8%	138.9°
2027-01-05 Tue	100	—	unknown	18:45–00:30 (good, 5.75 h)	79.1° 18:55	11.41	3%	127.7°
2027-01-06 Wed	100	—	unknown	18:50–00:25 (good, 5.58 h)	79.1° 18:50	11.39	1%	116.4°
2027-01-07 Thu	100	—	unknown	18:50–00:20 (good, 5.5 h)	79.1° 18:50	11.38	0%	105.0°
2027-01-08 Fri	100	—	unknown	18:50–00:15 (good, 5.42 h)	79.1° 18:45	11.36	1%	93.5°
2027-01-09 Sat	100	—	unknown	18:50–00:15 (good, 5.42 h)	79.1° 18:40	11.35	4%	82.0°
2027-01-10 Sun	100	—	unknown	18:50–00:10 (good, 5.33 h)	79.1° 18:35	11.33	8%	70.4°
2027-01-11 Mon	100	—	unknown	18:50–00:05 (good, 5.25 h)	79.1° 18:35	11.31	14%	58.8°
2027-01-12 Tue	93	—	unknown	18:55–00:00 (good, 5.08 h)	79.1° 18:30	11.29	22%	47.2°
2027-01-13 Wed	84	—	unknown	18:55–23:55 (good, 5.0 h)	79.1° 18:25	11.27	31%	35.6°
2027-01-14 Thu	74	—	unknown	18:55–23:35 (good, 4.67 h)	79.1° 18:20	11.25	40%	24.6°
2027-01-15 Fri	55	—	unknown	18:55–22:50 (good, 3.92 h)	79.1° 18:15	11.23	51%	16.0°
2027-01-16 Sat	39	—	unknown	18:55–00:05 (marginal, 5.17 h)	79.1° 18:15	11.21	62%	15.7°
2027-01-17 Sun	25	—	unknown	19:00–23:45 (marginal, 4.75 h)	79.1° 18:10	11.19	72%	24.7°
2027-01-18 Mon	21	—	unknown	19:00–23:25 (marginal, 4.42 h)	79.1° 18:05	11.16	82%	37.2°
2027-01-19 Tue	24	—	unknown	19:00–23:20 (marginal, 4.33 h)	79.1° 18:00	11.14	90%	50.9°
2027-01-20 Wed	33	—	unknown	19:00–23:25 (marginal, 4.42 h)	79.1° 17:55	11.11	96%	65.3°
2027-01-21 Thu	48	—	unknown	19:00–20:40 (good, 1.67 h)	79.1° 17:55	11.09	100%	80.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-12-23&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.