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: 12-09 (100), 12-10 (100), 12-11 (100), 12-12 (100), 12-13 (100) — by astronomy; check the weather when the night is within four days.

2028-12-09astronomy score per night — click a bar for that night2029-01-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-12-09 Sat	100	—	unknown	18:35–02:10 (good, 7.58 h)	79.1° 20:40	11.45	42%	142.3°
2028-12-10 Sun	100	—	unknown	18:35–02:10 (good, 7.58 h)	79.1° 20:35	11.46	31%	154.7°
2028-12-11 Mon	100	—	unknown	18:35–02:05 (good, 7.5 h)	79.1° 20:35	11.47	21%	164.1°
2028-12-12 Tue	100	—	unknown	18:35–02:00 (good, 7.42 h)	79.1° 20:30	11.48	12%	163.8°
2028-12-13 Wed	100	—	unknown	18:35–01:55 (good, 7.33 h)	79.1° 20:25	11.48	6%	154.1°
2028-12-14 Thu	100	—	unknown	18:35–01:55 (good, 7.33 h)	79.1° 20:20	11.49	2%	141.8°
2028-12-15 Fri	100	—	unknown	18:35–01:50 (good, 7.25 h)	79.1° 20:15	11.49	0%	128.9°
2028-12-16 Sat	100	—	unknown	18:35–01:45 (good, 7.17 h)	79.1° 20:15	11.5	1%	115.9°
2028-12-17 Sun	100	—	unknown	18:35–01:40 (good, 7.08 h)	79.1° 20:10	11.5	4%	103.1°
2028-12-18 Mon	100	—	unknown	18:35–01:35 (good, 7.0 h)	79.1° 20:05	11.51	9%	90.5°
2028-12-19 Tue	100	—	unknown	18:35–01:35 (good, 7.0 h)	79.1° 20:00	11.51	15%	78.3°
2028-12-20 Wed	100	—	unknown	18:35–01:30 (good, 6.92 h)	79.1° 19:55	11.51	23%	66.4°
2028-12-21 Thu	98	—	unknown	18:35–01:25 (good, 6.83 h)	79.1° 19:55	11.51	32%	54.9°
2028-12-22 Fri	90	—	unknown	18:35–01:20 (good, 6.75 h)	79.1° 19:50	11.51	41%	43.6°
2028-12-23 Sat	82	—	unknown	18:40–01:20 (good, 6.67 h)	79.1° 19:45	11.5	50%	32.8°
2028-12-24 Sun	62	—	unknown	21:25–23:40 (good, 2.25 h)	79.1° 19:40	11.5	60%	22.9°
2028-12-25 Mon	47	—	unknown	18:40–01:30 (marginal, 6.83 h)	79.1° 19:40	11.5	69%	15.6°
2028-12-26 Tue	32	—	unknown	18:40–01:15 (marginal, 6.58 h)	79.1° 19:35	11.49	77%	15.6°
2028-12-27 Wed	23	—	unknown	18:40–00:50 (marginal, 6.17 h)	79.1° 19:30	11.49	85%	23.2°
2028-12-28 Thu	21	—	unknown	18:40–22:20 (marginal, 3.67 h)	79.1° 19:25	11.48	92%	33.9°
2028-12-29 Fri	29	—	unknown	18:40–00:10 (marginal, 5.5 h)	79.1° 19:20	11.47	96%	45.9°
2028-12-30 Sat	42	—	unknown	18:40–00:35 (marginal, 5.92 h)	79.1° 19:20	11.47	99%	58.5°
2028-12-31 Sun	60	—	unknown	18:45–20:30 (good, 1.75 h)	79.1° 19:15	11.46	100%	71.6°
2029-01-01 Mon	78	—	unknown	18:45–22:40 (good, 3.92 h)	79.1° 19:10	11.45	98%	85.1°
2029-01-02 Tue	100	—	unknown	18:45–00:05 (good, 5.33 h)	79.1° 19:05	11.44	94%	98.7°
2029-01-03 Wed	100	—	unknown	18:45–00:20 (good, 5.58 h)	79.1° 19:00	11.42	87%	112.5°
2029-01-04 Thu	100	—	unknown	18:45–00:20 (good, 5.58 h)	79.1° 19:00	11.41	78%	126.1°
2029-01-05 Fri	100	—	unknown	18:45–00:20 (good, 5.58 h)	79.1° 18:55	11.4	68%	139.5°
2029-01-06 Sat	100	—	unknown	18:50–00:20 (good, 5.5 h)	79.1° 18:50	11.38	57%	152.2°
2029-01-07 Sun	100	—	unknown	18:50–00:20 (good, 5.5 h)	79.1° 18:45	11.37	46%	162.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-12-09&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.