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: 12-17 (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.

2042-12-17astronomy score per night — click a bar for that night2043-01-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-12-17 Wed	100	—	unknown	18:35–01:45 (good, 7.17 h)	79.2° 20:10	11.5	28%	66.5°
2042-12-18 Thu	97	—	unknown	18:35–01:40 (good, 7.08 h)	79.2° 20:05	11.5	38%	53.8°
2042-12-19 Fri	87	—	unknown	18:35–01:35 (good, 7.0 h)	79.2° 20:05	11.51	49%	41.3°
2042-12-20 Sat	67	—	unknown	21:05–01:00 (good, 3.92 h)	79.2° 20:00	11.51	60%	29.4°
2042-12-21 Sun	48	—	unknown	18:35–01:50 (marginal, 7.25 h)	79.2° 19:55	11.51	71%	20.1°
2042-12-22 Mon	31	—	unknown	18:35–01:30 (marginal, 6.92 h)	79.2° 19:50	11.51	81%	18.3°
2042-12-23 Tue	22	—	unknown	18:40–01:00 (marginal, 6.33 h)	79.2° 19:50	11.51	89%	26.1°
2042-12-24 Wed	24	—	unknown	18:40–22:20 (marginal, 3.67 h)	79.2° 19:45	11.5	95%	37.9°
2042-12-25 Thu	36	—	unknown	18:40–00:45 (marginal, 6.08 h)	79.2° 19:40	11.5	99%	51.0°
2042-12-26 Fri	54	—	unknown	18:40–19:15 (good, 0.58 h)	79.2° 19:35	11.5	100%	64.4°
2042-12-27 Sat	74	—	unknown	18:40–22:10 (good, 3.5 h)	79.2° 19:30	11.49	98%	77.8°
2042-12-28 Sun	100	—	unknown	18:40–23:40 (good, 5.0 h)	79.2° 19:30	11.48	94%	90.8°
2042-12-29 Mon	100	—	unknown	18:40–00:35 (good, 5.92 h)	79.2° 19:25	11.48	88%	103.6°
2042-12-30 Tue	100	—	unknown	18:40–00:40 (good, 6.0 h)	79.2° 19:20	11.47	80%	115.8°
2042-12-31 Wed	100	—	unknown	18:45–00:40 (good, 5.92 h)	79.2° 19:15	11.46	72%	127.6°
2043-01-01 Thu	100	—	unknown	18:45–00:40 (good, 5.92 h)	79.2° 19:10	11.45	62%	138.7°
2043-01-02 Fri	100	—	unknown	18:45–00:35 (good, 5.83 h)	79.2° 19:10	11.44	53%	149.0°
2043-01-03 Sat	100	—	unknown	18:45–00:35 (good, 5.83 h)	79.2° 19:05	11.43	44%	157.6°
2043-01-04 Sun	100	—	unknown	18:45–00:35 (good, 5.83 h)	79.2° 19:00	11.42	34%	162.3°
2043-01-05 Mon	100	—	unknown	18:45–00:30 (good, 5.75 h)	79.2° 18:55	11.4	26%	160.0°
2043-01-06 Tue	100	—	unknown	18:50–00:25 (good, 5.58 h)	79.2° 18:55	11.39	18%	152.4°
2043-01-07 Wed	100	—	unknown	18:50–00:20 (good, 5.5 h)	79.2° 18:50	11.38	11%	142.4°
2043-01-08 Thu	100	—	unknown	18:50–00:15 (good, 5.42 h)	79.2° 18:45	11.36	6%	131.4°
2043-01-09 Fri	100	—	unknown	18:50–00:15 (good, 5.42 h)	79.2° 18:40	11.34	2%	119.7°
2043-01-10 Sat	100	—	unknown	18:50–00:10 (good, 5.33 h)	79.2° 18:35	11.33	0%	107.6°
2043-01-11 Sun	100	—	unknown	18:50–00:05 (good, 5.25 h)	79.2° 18:35	11.31	1%	95.1°
2043-01-12 Mon	100	—	unknown	18:55–00:00 (good, 5.08 h)	79.2° 18:30	11.29	3%	82.4°
2043-01-13 Tue	100	—	unknown	18:55–00:00 (good, 5.08 h)	79.2° 18:25	11.27	8%	69.5°
2043-01-14 Wed	100	—	unknown	18:55–23:55 (good, 5.0 h)	79.2° 18:20	11.25	15%	56.5°
2043-01-15 Thu	90	—	unknown	18:55–23:50 (good, 4.92 h)	79.2° 18:15	11.23	24%	43.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-12-17&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.