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: 10-21 (100), 10-22 (100), 10-23 (100), 10-24 (100), 10-25 (100) — by astronomy; check the weather when the night is within four days.

2027-10-18astronomy score per night — click a bar for that night2027-11-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-18 Mon	53	—	unknown	20:10–06:05 (marginal, 9.92 h)	79.1° 01:10	9.94	88%	35.6°
2027-10-19 Tue	86	—	unknown	20:10–00:00 (good, 3.83 h)	79.1° 01:05	9.98	80%	48.3°
2027-10-20 Wed	94	—	unknown	20:10–03:50 (good, 7.67 h)	79.1° 01:00	10.02	70%	61.4°
2027-10-21 Thu	100	—	unknown	20:05–05:40 (good, 9.58 h)	79.1° 00:55	10.07	59%	74.8°
2027-10-22 Fri	100	—	unknown	20:05–06:05 (good, 10.0 h)	79.1° 00:50	10.11	48%	88.5°
2027-10-23 Sat	100	—	unknown	20:05–06:10 (good, 10.08 h)	79.1° 00:50	10.15	36%	102.2°
2027-10-24 Sun	100	—	unknown	20:00–06:15 (good, 10.25 h)	79.1° 00:45	10.19	26%	115.9°
2027-10-25 Mon	100	—	unknown	20:00–06:10 (good, 10.17 h)	79.1° 00:40	10.23	16%	129.6°
2027-10-26 Tue	100	—	unknown	20:00–06:10 (good, 10.17 h)	79.1° 00:35	10.27	9%	142.9°
2027-10-27 Wed	100	—	unknown	20:00–06:05 (good, 10.08 h)	79.1° 00:30	10.31	4%	155.2°
2027-10-28 Thu	100	—	unknown	19:55–06:00 (good, 10.08 h)	79.1° 00:30	10.34	1%	164.3°
2027-10-29 Fri	100	—	unknown	19:55–05:55 (good, 10.0 h)	79.1° 00:25	10.38	0%	163.9°
2027-10-30 Sat	100	—	unknown	19:55–04:55 (good, 10.0 h)	79.1° 00:20	10.42	2%	154.8°
2027-10-31 Sun	100	—	unknown	18:55–04:50 (good, 9.92 h)	79.1° 23:15	10.46	6%	143.4°
2027-11-01 Mon	100	—	unknown	18:55–04:45 (good, 9.83 h)	79.1° 23:15	10.49	12%	131.5°
2027-11-02 Tue	100	—	unknown	18:50–04:40 (good, 9.83 h)	79.1° 23:10	10.53	20%	119.6°
2027-11-03 Wed	100	—	unknown	18:50–04:35 (good, 9.75 h)	79.1° 23:05	10.57	28%	107.8°
2027-11-04 Thu	100	—	unknown	18:50–04:35 (good, 9.75 h)	79.1° 23:00	10.6	37%	96.2°
2027-11-05 Fri	100	—	unknown	18:50–04:30 (good, 9.67 h)	79.1° 22:55	10.64	46%	84.7°
2027-11-06 Sat	100	—	unknown	18:45–04:25 (good, 9.67 h)	79.1° 22:55	10.67	56%	73.2°
2027-11-07 Sun	100	—	unknown	18:45–04:20 (good, 9.58 h)	79.1° 22:50	10.7	65%	61.8°
2027-11-08 Mon	93	—	unknown	21:10–04:15 (good, 7.08 h)	79.1° 22:45	10.74	74%	50.3°
2027-11-09 Tue	85	—	unknown	03:00–04:15 (good, 1.25 h)	79.1° 22:40	10.77	82%	38.9°
2027-11-10 Wed	61	—	unknown	04:05–04:10 (good, 0.08 h)	79.1° 22:35	10.8	89%	27.9°
2027-11-11 Thu	36	—	unknown	22:55–04:15 (marginal, 5.33 h)	79.1° 22:35	10.83	94%	18.2°
2027-11-12 Fri	27	—	unknown	18:40–20:40 (marginal, 2.0 h)	79.1° 22:30	10.86	98%	14.5°
2027-11-13 Sat	27	—	unknown	18:40–20:55 (marginal, 2.25 h)	79.1° 22:25	10.89	100%	20.7°
2027-11-14 Sun	33	—	unknown	18:40–22:00 (marginal, 3.33 h)	79.1° 22:20	10.92	99%	31.9°
2027-11-15 Mon	56	—	unknown	18:40–02:30 (marginal, 7.83 h)	79.1° 22:20	10.95	96%	44.7°
2027-11-16 Tue	91	—	unknown	18:40–21:40 (good, 3.0 h)	79.1° 22:15	10.98	90%	58.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-18&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.