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: 12-22 (100), 12-23 (100), 12-24 (100), 12-25 (100), 12-26 (100) — by astronomy; check the weather when the night is within four days.

2027-12-22astronomy score per night — click a bar for that night2028-01-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-12-22 Wed	100	—	unknown	18:35–01:25 (good, 6.83 h)	79.1° 19:50	11.51	24%	165.8°
2027-12-23 Thu	100	—	unknown	18:40–01:20 (good, 6.67 h)	79.1° 19:50	11.51	15%	160.9°
2027-12-24 Fri	100	—	unknown	18:40–01:15 (good, 6.58 h)	79.1° 19:45	11.5	8%	150.7°
2027-12-25 Sat	100	—	unknown	18:40–01:15 (good, 6.58 h)	79.1° 19:40	11.5	4%	139.2°
2027-12-26 Sun	100	—	unknown	18:40–01:10 (good, 6.5 h)	79.1° 19:35	11.5	1%	127.4°
2027-12-27 Mon	100	—	unknown	18:40–01:05 (good, 6.42 h)	79.1° 19:35	11.49	0%	115.5°
2027-12-28 Tue	100	—	unknown	18:40–01:00 (good, 6.33 h)	79.1° 19:30	11.49	1%	103.7°
2027-12-29 Wed	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.1° 19:25	11.48	4%	92.0°
2027-12-30 Thu	100	—	unknown	18:40–00:55 (good, 6.25 h)	79.1° 19:20	11.47	9%	80.4°
2027-12-31 Fri	100	—	unknown	18:45–00:50 (good, 6.08 h)	79.1° 19:15	11.46	15%	69.0°
2028-01-01 Sat	100	—	unknown	18:45–00:45 (good, 6.0 h)	79.1° 19:15	11.45	22%	57.6°
2028-01-02 Sun	92	—	unknown	18:45–00:40 (good, 5.92 h)	79.1° 19:10	11.44	30%	46.4°
2028-01-03 Mon	84	—	unknown	18:45–00:35 (good, 5.83 h)	79.1° 19:05	11.43	39%	35.3°
2028-01-04 Tue	70	—	unknown	18:45–00:10 (good, 5.42 h)	79.1° 19:00	11.42	49%	24.8°
2028-01-05 Wed	55	—	unknown	18:45–00:55 (marginal, 6.17 h)	79.1° 18:55	11.41	58%	16.3°
2028-01-06 Thu	38	—	unknown	18:45–00:45 (marginal, 6.0 h)	79.1° 18:55	11.4	68%	14.8°
2028-01-07 Fri	25	—	unknown	18:50–00:20 (marginal, 5.5 h)	79.1° 18:50	11.38	78%	22.4°
2028-01-08 Sat	20	—	unknown	18:50–23:55 (marginal, 5.08 h)	79.1° 18:45	11.37	86%	34.0°
2028-01-09 Sun	25	—	unknown	18:50–23:50 (marginal, 5.0 h)	79.1° 18:40	11.35	93%	47.0°
2028-01-10 Mon	37	—	unknown	18:50–00:00 (marginal, 5.17 h)	79.1° 18:40	11.33	98%	60.9°
2028-01-11 Tue	53	—	unknown	18:50–20:35 (good, 1.75 h)	79.1° 18:35	11.31	100%	75.2°
2028-01-12 Wed	74	—	unknown	18:55–22:25 (good, 3.5 h)	79.1° 18:30	11.3	99%	89.8°
2028-01-13 Thu	100	—	unknown	18:55–23:35 (good, 4.67 h)	79.1° 18:25	11.28	95%	104.4°
2028-01-14 Fri	100	—	unknown	18:55–23:45 (good, 4.83 h)	79.1° 18:20	11.26	89%	118.9°
2028-01-15 Sat	100	—	unknown	18:55–23:40 (good, 4.75 h)	79.1° 18:20	11.24	80%	133.0°
2028-01-16 Sun	100	—	unknown	18:55–23:40 (good, 4.75 h)	79.1° 18:15	11.21	70%	146.3°
2028-01-17 Mon	100	—	unknown	19:00–23:40 (good, 4.67 h)	79.1° 18:10	11.19	60%	158.1°
2028-01-18 Tue	100	—	unknown	19:00–23:40 (good, 4.67 h)	79.1° 18:05	11.17	49%	165.6°
2028-01-19 Wed	100	—	unknown	19:00–23:35 (good, 4.58 h)	79.1° 18:00	11.14	38%	162.8°
2028-01-20 Thu	100	—	unknown	19:00–23:30 (good, 4.5 h)	79.1° 18:00	11.12	28%	153.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-12-22&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.