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: 01-19 (100), 01-20 (100), 01-21 (100), 01-22 (100), 01-23 (100) — by astronomy; check the weather when the night is within four days.

2041-01-18astronomy score per night — click a bar for that night2041-02-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-01-18 Fri	81	—	unknown	19:00–23:05 (good, 4.08 h)	79.2° 18:05	11.15	97%	101.2°
2041-01-19 Sat	100	—	unknown	19:00–23:15 (good, 4.25 h)	79.2° 18:00	11.12	94%	112.2°
2041-01-20 Sun	100	—	unknown	19:00–23:20 (good, 4.33 h)	79.2° 17:55	11.1	88%	123.1°
2041-01-21 Mon	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.2° 17:50	11.07	82%	133.7°
2041-01-22 Tue	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.2° 17:50	11.05	74%	143.8°
2041-01-23 Wed	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.2° 17:45	11.02	65%	152.6°
2041-01-24 Thu	100	—	unknown	19:05–23:10 (good, 4.08 h)	79.2° 17:40	10.99	55%	158.4°
2041-01-25 Fri	100	—	unknown	19:05–23:10 (good, 4.08 h)	79.2° 17:35	10.96	45%	158.0°
2041-01-26 Sat	100	—	unknown	19:10–23:05 (good, 3.92 h)	79.2° 17:30	10.93	34%	151.1°
2041-01-27 Sun	100	—	unknown	19:10–23:00 (good, 3.83 h)	79.2° 17:30	10.9	24%	140.7°
2041-01-28 Mon	99	—	unknown	19:10–22:55 (good, 3.75 h)	79.2° 17:25	10.87	15%	128.4°
2041-01-29 Tue	97	—	unknown	19:10–22:55 (good, 3.75 h)	79.2° 17:20	10.84	8%	115.1°
2041-01-30 Wed	96	—	unknown	19:10–22:50 (good, 3.67 h)	79.2° 17:15	10.81	3%	101.2°
2041-01-31 Thu	93	—	unknown	19:15–22:45 (good, 3.5 h)	79.2° 17:10	10.78	0%	87.0°
2041-02-01 Fri	91	—	unknown	19:15–22:40 (good, 3.42 h)	79.2° 17:10	10.75	1%	72.7°
2041-02-02 Sat	88	—	unknown	19:15–22:35 (good, 3.33 h)	79.2° 17:05	10.71	5%	58.7°
2041-02-03 Sun	81	—	unknown	19:15–22:35 (good, 3.33 h)	79.2° 17:00	10.68	11%	45.4°
2041-02-04 Mon	70	—	unknown	19:20–22:30 (good, 3.17 h)	79.2° 16:55	10.64	19%	33.5°
2041-02-05 Tue	56	—	unknown	19:20–22:10 (good, 2.83 h)	79.2° 16:55	10.61	29%	24.2°
2041-02-06 Wed	43	—	unknown	19:20–22:00 (good, 2.67 h)	79.2° 16:50	10.57	39%	20.8°
2041-02-07 Thu	32	—	unknown	19:20–20:00 (good, 0.67 h)	79.2° 16:45	10.54	50%	24.9°
2041-02-08 Fri	24	—	unknown	19:20–22:30 (marginal, 3.17 h)	79.2° 16:40	10.5	60%	33.4°
2041-02-09 Sat	20	—	unknown	19:25–22:20 (marginal, 2.92 h)	79.2° 16:35	10.46	69%	43.5°
2041-02-10 Sun	19	—	unknown	19:25–22:10 (marginal, 2.75 h)	79.2° 16:35	10.43	78%	54.3°
2041-02-11 Mon	20	—	unknown	19:25–22:10 (marginal, 2.75 h)	79.2° 16:30	10.39	85%	65.3°
2041-02-12 Tue	24	—	unknown	19:25–22:10 (marginal, 2.75 h)	79.2° 16:25	10.35	91%	76.3°
2041-02-13 Wed	27	—	unknown	19:30–20:05 (good, 0.58 h)	79.2° 16:20	10.31	96%	87.4°
2041-02-14 Thu	33	—	unknown	19:30–21:00 (good, 1.5 h)	79.2° 16:15	10.27	99%	98.5°
2041-02-15 Fri	39	—	unknown	19:30–21:25 (good, 1.92 h)	79.2° 16:15	10.23	100%	109.5°
2041-02-16 Sat	44	—	unknown	19:30–21:30 (good, 2.0 h)	79.2° 16:10	10.19	99%	120.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-01-18&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.