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: 12-10 (100), 12-11 (100), 12-12 (100), 12-13 (100), 12-14 (100) — by astronomy; check the weather when the night is within four days.

2041-12-10astronomy score per night — click a bar for that night2042-01-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-12-10 Tue	100	—	unknown	18:35–00:20 (good, 5.75 h)	79.2° 20:40	11.46	89%	83.2°
2041-12-11 Wed	100	—	unknown	18:35–01:35 (good, 7.0 h)	79.2° 20:35	11.47	82%	94.9°
2041-12-12 Thu	100	—	unknown	18:35–01:45 (good, 7.17 h)	79.2° 20:30	11.47	74%	106.4°
2041-12-13 Fri	100	—	unknown	18:35–01:50 (good, 7.25 h)	79.2° 20:25	11.48	65%	117.6°
2041-12-14 Sat	100	—	unknown	18:35–01:50 (good, 7.25 h)	79.2° 20:20	11.49	56%	128.5°
2041-12-15 Sun	100	—	unknown	18:35–01:45 (good, 7.17 h)	79.2° 20:20	11.49	47%	138.9°
2041-12-16 Mon	100	—	unknown	18:35–01:45 (good, 7.17 h)	79.2° 20:15	11.5	37%	148.7°
2041-12-17 Tue	100	—	unknown	18:35–01:45 (good, 7.17 h)	79.2° 20:10	11.5	28%	156.8°
2041-12-18 Wed	100	—	unknown	18:35–01:40 (good, 7.08 h)	79.2° 20:05	11.5	20%	160.5°
2041-12-19 Thu	100	—	unknown	18:35–01:35 (good, 7.0 h)	79.2° 20:00	11.51	13%	157.4°
2041-12-20 Fri	100	—	unknown	18:35–01:30 (good, 6.92 h)	79.2° 20:00	11.51	7%	149.0°
2041-12-21 Sat	100	—	unknown	18:35–01:25 (good, 6.83 h)	79.2° 19:55	11.51	2%	138.2°
2041-12-22 Sun	100	—	unknown	18:35–01:25 (good, 6.83 h)	79.2° 19:50	11.51	0%	126.1°
2041-12-23 Mon	100	—	unknown	18:40–01:20 (good, 6.67 h)	79.2° 19:45	11.51	1%	113.3°
2041-12-24 Tue	100	—	unknown	18:40–01:15 (good, 6.58 h)	79.2° 19:45	11.5	3%	100.1°
2041-12-25 Wed	100	—	unknown	18:40–01:10 (good, 6.5 h)	79.2° 19:40	11.5	9%	86.7°
2041-12-26 Thu	100	—	unknown	18:40–01:05 (good, 6.42 h)	79.2° 19:35	11.49	16%	73.2°
2041-12-27 Fri	100	—	unknown	18:40–01:05 (good, 6.42 h)	79.2° 19:30	11.49	26%	59.9°
2041-12-28 Sat	92	—	unknown	18:40–01:00 (good, 6.33 h)	79.2° 19:25	11.48	36%	46.9°
2041-12-29 Sun	82	—	unknown	18:40–00:55 (good, 6.25 h)	79.2° 19:25	11.48	48%	34.8°
2041-12-30 Mon	62	—	unknown	20:50–23:05 (good, 2.25 h)	79.2° 19:20	11.47	59%	24.5°
2041-12-31 Tue	42	—	unknown	18:45–01:10 (marginal, 6.42 h)	79.2° 19:15	11.46	70%	19.4°
2042-01-01 Wed	28	—	unknown	18:45–00:45 (marginal, 6.0 h)	79.2° 19:10	11.45	79%	22.8°
2042-01-02 Thu	21	—	unknown	18:45–00:20 (marginal, 5.58 h)	79.2° 19:05	11.44	87%	31.9°
2042-01-03 Fri	25	—	unknown	18:45–00:10 (marginal, 5.42 h)	79.2° 19:05	11.43	94%	43.1°
2042-01-04 Sat	34	—	unknown	18:45–00:15 (marginal, 5.5 h)	79.2° 19:00	11.41	98%	55.0°
2042-01-05 Sun	48	—	unknown	18:45–19:05 (good, 0.33 h)	79.2° 18:55	11.4	100%	67.1°
2042-01-06 Mon	65	—	unknown	18:50–21:35 (good, 2.75 h)	79.2° 18:50	11.39	100%	79.1°
2042-01-07 Tue	80	—	unknown	18:50–22:50 (good, 4.0 h)	79.2° 18:50	11.37	97%	90.9°
2042-01-08 Wed	100	—	unknown	18:50–23:50 (good, 5.0 h)	79.2° 18:45	11.36	93%	102.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-12-10&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.