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 HD 189733: 01-03 (4), 01-04 (3), 01-05 (2), 01-06 (2), 01-07 (1) — by astronomy; check the weather when the night is within four days.

2028-01-03astronomy score per night — click a bar for that night2028-02-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-01-03 Mon	4	—	unknown	18:45–19:05 (marginal, 0.33 h)	71.1° 13:30	11.43	39%	59.3°
2028-01-04 Tue	3	—	unknown	18:45–19:00 (marginal, 0.25 h)	71.1° 13:30	11.42	49%	67.4°
2028-01-05 Wed	2	—	unknown	18:45–18:55 (marginal, 0.17 h)	71.1° 13:25	11.41	58%	76.3°
2028-01-06 Thu	2	—	unknown	18:45–18:55 (marginal, 0.17 h)	71.1° 13:20	11.4	68%	85.7°
2028-01-07 Fri	1	—	unknown	—	71.1° 13:15	11.38	78%	95.6°
2028-01-08 Sat	1	—	unknown	—	71.1° 13:15	11.37	86%	105.6°
2028-01-09 Sun	1	—	unknown	—	71.1° 13:10	11.35	93%	115.6°
2028-01-10 Mon	1	—	unknown	—	71.1° 13:05	11.33	98%	124.9°
2028-01-11 Tue	1	—	unknown	—	71.1° 13:00	11.31	100%	132.6°
2028-01-12 Wed	0	—	unknown	—	71.1° 12:55	11.3	99%	137.6°
2028-01-13 Thu	0	—	unknown	—	71.1° 12:55	11.28	95%	138.4°
2028-01-14 Fri	0	—	unknown	—	71.1° 12:50	11.26	89%	135.0°
2028-01-15 Sat	0	—	unknown	—	71.1° 12:45	11.24	80%	128.2°
2028-01-16 Sun	0	—	unknown	—	71.1° 12:40	11.21	70%	119.6°
2028-01-17 Mon	0	—	unknown	—	71.1° 12:35	11.19	60%	110.0°
2028-01-18 Tue	0	—	unknown	—	71.1° 12:35	11.17	49%	100.1°
2028-01-19 Wed	0	—	unknown	—	71.1° 12:30	11.14	38%	90.1°
2028-01-20 Thu	0	—	unknown	—	71.1° 12:25	11.12	28%	80.4°
2028-01-21 Fri	0	—	unknown	—	71.1° 12:20	11.09	20%	71.1°
2028-01-22 Sat	0	—	unknown	—	71.1° 12:20	11.07	12%	62.5°
2028-01-23 Sun	0	—	unknown	—	71.1° 12:15	11.04	7%	54.7°
2028-01-24 Mon	0	—	unknown	—	71.1° 12:10	11.01	3%	48.3°
2028-01-25 Tue	0	—	unknown	—	71.1° 12:05	10.99	0%	43.7°
2028-01-26 Wed	0	—	unknown	—	71.1° 12:00	10.96	0%	41.5°
2028-01-27 Thu	0	—	unknown	—	71.1° 11:55	10.93	2%	42.0°
2028-01-28 Fri	1	—	unknown	—	71.1° 11:50	10.9	5%	45.2°
2028-01-29 Sat	1	—	unknown	—	71.1° 11:45	10.87	10%	50.4°
2028-01-30 Sun	1	—	unknown	—	71.1° 11:40	10.84	16%	57.2°
2028-01-31 Mon	1	—	unknown	—	71.1° 11:40	10.81	23%	65.0°
2028-02-01 Tue	1	—	unknown	—	71.1° 11:35	10.77	32%	73.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-01-03&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.