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: 01-13 (100), 01-14 (100), 01-15 (100), 01-16 (100), 01-17 (100) — by astronomy; check the weather when the night is within four days.

2028-01-04astronomy score per night — click a bar for that night2028-02-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2028-01-21 Fri	100	—	unknown	19:00–23:25 (good, 4.42 h)	79.1° 17:55	11.09	20%	142.0°
2028-01-22 Sat	100	—	unknown	19:05–23:25 (good, 4.33 h)	79.1° 17:50	11.07	12%	130.3°
2028-01-23 Sun	100	—	unknown	19:05–23:20 (good, 4.25 h)	79.1° 17:45	11.04	7%	118.5°
2028-01-24 Mon	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.1° 17:40	11.01	3%	106.8°
2028-01-25 Tue	100	—	unknown	19:05–23:10 (good, 4.08 h)	79.1° 17:40	10.99	0%	95.2°
2028-01-26 Wed	100	—	unknown	19:05–23:05 (good, 4.0 h)	79.1° 17:35	10.96	0%	83.6°
2028-01-27 Thu	100	—	unknown	19:10–23:05 (good, 3.92 h)	79.1° 17:30	10.93	2%	72.1°
2028-01-28 Fri	100	—	unknown	19:10–23:00 (good, 3.83 h)	79.1° 17:25	10.9	5%	60.7°
2028-01-29 Sat	93	—	unknown	19:10–22:55 (good, 3.75 h)	79.1° 17:25	10.87	10%	49.4°
2028-01-30 Sun	85	—	unknown	19:10–22:50 (good, 3.67 h)	79.1° 17:20	10.84	16%	38.3°
2028-01-31 Mon	72	—	unknown	19:15–22:45 (good, 3.5 h)	79.1° 17:15	10.81	23%	27.7°
2028-02-01 Tue	59	—	unknown	19:15–22:30 (good, 3.25 h)	79.1° 17:10	10.77	32%	18.4°
2028-02-02 Wed	47	—	unknown	19:15–22:15 (good, 3.0 h)	79.1° 17:05	10.74	41%	14.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-01-04&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.