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: 01-17 (100), 01-18 (100), 01-19 (100), 01-20 (100), 01-21 (100) — by astronomy; check the weather when the night is within four days.

2028-01-17astronomy score per night — click a bar for that night2028-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2028-02-03 Thu	34	—	unknown	19:15–19:45 (good, 0.5 h)	79.1° 17:05	10.71	51%	19.1°
2028-02-04 Fri	24	—	unknown	19:15–22:45 (marginal, 3.5 h)	79.1° 17:00	10.67	62%	29.3°
2028-02-05 Sat	20	—	unknown	19:20–22:35 (marginal, 3.25 h)	79.1° 16:55	10.64	72%	41.5°
2028-02-06 Sun	21	—	unknown	19:20–22:25 (marginal, 3.08 h)	79.1° 16:50	10.6	81%	54.7°
2028-02-07 Mon	25	—	unknown	19:20–22:25 (marginal, 3.08 h)	79.1° 16:45	10.57	90%	68.5°
2028-02-08 Tue	32	—	unknown	19:20–20:00 (good, 0.67 h)	79.1° 16:45	10.53	96%	82.9°
2028-02-09 Wed	41	—	unknown	19:25–21:20 (good, 1.92 h)	79.1° 16:40	10.49	99%	97.6°
2028-02-10 Thu	51	—	unknown	19:25–21:50 (good, 2.42 h)	79.1° 16:35	10.46	100%	112.3°
2028-02-11 Fri	57	—	unknown	19:25–21:55 (good, 2.5 h)	79.1° 16:30	10.42	97%	127.0°
2028-02-12 Sat	63	—	unknown	19:25–21:50 (good, 2.42 h)	79.1° 16:30	10.38	92%	141.1°
2028-02-13 Sun	63	—	unknown	19:25–21:55 (good, 2.5 h)	79.1° 16:25	10.34	84%	154.2°
2028-02-14 Mon	60	—	unknown	19:30–21:50 (good, 2.33 h)	79.1° 16:20	10.3	75%	164.0°
2028-02-15 Tue	58	—	unknown	19:30–21:50 (good, 2.33 h)	79.1° 16:15	10.27	65%	164.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-01-17&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.