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: 01-06 (2), 01-07 (2), 02-04 (2), 01-08 (1), 01-09 (1) — by astronomy; check the weather when the night is within four days.

2045-01-06astronomy score per night — click a bar for that night2045-02-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-01-06 Fri	2	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.1° 13:20	11.38	83%	131.4°
2045-01-07 Sat	2	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:15	11.37	73%	124.9°
2045-01-08 Sun	1	—	unknown	—	71.1° 13:10	11.35	63%	116.9°
2045-01-09 Mon	1	—	unknown	—	71.1° 13:05	11.33	52%	108.1°
2045-01-10 Tue	1	—	unknown	—	71.1° 13:00	11.32	42%	99.0°
2045-01-11 Wed	1	—	unknown	—	71.1° 13:00	11.3	32%	90.0°
2045-01-12 Thu	0	—	unknown	—	71.1° 12:55	11.28	23%	81.1°
2045-01-13 Fri	0	—	unknown	—	71.1° 12:50	11.26	16%	72.6°
2045-01-14 Sat	0	—	unknown	—	71.1° 12:45	11.24	9%	64.6°
2045-01-15 Sun	0	—	unknown	—	71.1° 12:45	11.22	5%	57.4°
2045-01-16 Mon	0	—	unknown	—	71.1° 12:40	11.19	2%	51.4°
2045-01-17 Tue	0	—	unknown	—	71.1° 12:35	11.17	0%	46.8°
2045-01-18 Wed	0	—	unknown	—	71.1° 12:30	11.15	0%	44.4°
2045-01-19 Thu	0	—	unknown	—	71.1° 12:25	11.12	3%	44.3°
2045-01-20 Fri	0	—	unknown	—	71.1° 12:25	11.1	7%	46.8°
2045-01-21 Sat	0	—	unknown	—	71.1° 12:20	11.07	12%	51.4°
2045-01-22 Sun	0	—	unknown	—	71.1° 12:15	11.05	19%	57.7°
2045-01-23 Mon	0	—	unknown	—	71.1° 12:10	11.02	27%	65.2°
2045-01-24 Tue	0	—	unknown	—	71.1° 12:05	10.99	37%	73.6°
2045-01-25 Wed	0	—	unknown	—	71.1° 12:00	10.96	47%	82.7°
2045-01-26 Thu	0	—	unknown	—	71.1° 11:55	10.93	58%	92.2°
2045-01-27 Fri	1	—	unknown	—	71.1° 11:50	10.9	68%	102.0°
2045-01-28 Sat	1	—	unknown	—	71.1° 11:50	10.87	78%	111.7°
2045-01-29 Sun	1	—	unknown	—	71.1° 11:45	10.84	87%	120.9°
2045-01-30 Mon	1	—	unknown	—	71.1° 11:40	10.81	94%	128.7°
2045-01-31 Tue	1	—	unknown	—	71.1° 11:35	10.78	99%	134.2°
2045-02-01 Wed	1	—	unknown	—	71.1° 11:30	10.74	100%	136.0°
2045-02-02 Thu	1	—	unknown	—	71.1° 11:30	10.71	98%	133.7°
2045-02-03 Fri	1	—	unknown	—	71.1° 11:25	10.68	94%	128.0°
2045-02-04 Sat	2	—	unknown	05:50–05:55 (marginal, 0.08 h)	71.1° 11:20	10.64	87%	120.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-01-06&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.