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: 03-07 (26), 03-08 (26), 03-05 (25), 03-06 (25), 03-04 (24) — by astronomy; check the weather when the night is within four days.

2047-02-09astronomy score per night — click a bar for that night2047-03-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-02-09 Sat	4	—	unknown	05:35–05:50 (marginal, 0.25 h)	71.1° 11:00	10.48	99%	139.3°
2047-02-10 Sun	4	—	unknown	05:30–05:50 (marginal, 0.33 h)	71.1° 11:00	10.44	100%	137.5°
2047-02-11 Mon	5	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.2° 10:55	10.41	98%	132.0°
2047-02-12 Tue	6	—	unknown	05:20–05:50 (marginal, 0.5 h)	71.2° 10:50	10.37	92%	123.8°
2047-02-13 Wed	5	—	unknown	05:20–05:45 (marginal, 0.42 h)	71.1° 10:45	10.33	85%	114.1°
2047-02-14 Thu	6	—	unknown	05:15–05:45 (marginal, 0.5 h)	71.1° 10:45	10.29	76%	103.6°
2047-02-15 Fri	6	—	unknown	05:10–05:45 (marginal, 0.58 h)	71.1° 10:40	10.25	65%	92.8°
2047-02-16 Sat	7	—	unknown	05:05–05:45 (marginal, 0.67 h)	71.2° 10:35	10.21	54%	82.1°
2047-02-17 Sun	8	—	unknown	05:00–05:40 (marginal, 0.67 h)	71.1° 10:30	10.17	43%	71.8°
2047-02-18 Mon	9	—	unknown	05:35–05:40 (good, 0.08 h)	71.1° 10:25	10.13	32%	62.2°
2047-02-19 Tue	11	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:25	10.09	22%	53.7°
2047-02-20 Wed	13	—	unknown	05:20–05:40 (good, 0.33 h)	71.1° 10:20	10.04	14%	46.8°
2047-02-21 Thu	14	—	unknown	05:15–05:35 (good, 0.33 h)	71.2° 10:15	10.0	8%	42.3°
2047-02-22 Fri	15	—	unknown	05:10–05:35 (good, 0.42 h)	71.1° 10:10	9.96	3%	40.7°
2047-02-23 Sat	17	—	unknown	05:05–05:35 (good, 0.5 h)	71.1° 10:05	9.92	1%	42.4°
2047-02-24 Sun	18	—	unknown	05:00–05:35 (good, 0.58 h)	71.1° 10:05	9.87	0%	46.7°
2047-02-25 Mon	18	—	unknown	05:00–05:30 (good, 0.5 h)	71.2° 10:00	9.83	1%	53.0°
2047-02-26 Tue	19	—	unknown	04:55–05:30 (good, 0.58 h)	71.2° 09:55	9.79	4%	60.4°
2047-02-27 Wed	20	—	unknown	04:50–05:30 (good, 0.67 h)	71.1° 09:50	9.74	9%	68.7°
2047-02-28 Thu	20	—	unknown	04:45–05:25 (good, 0.67 h)	71.1° 09:50	9.7	15%	77.3°
2047-03-01 Fri	21	—	unknown	04:40–05:25 (good, 0.75 h)	71.1° 09:45	9.65	23%	86.2°
2047-03-02 Sat	23	—	unknown	04:40–05:25 (good, 0.75 h)	71.2° 09:40	9.61	31%	95.2°
2047-03-03 Sun	23	—	unknown	04:35–05:20 (good, 0.75 h)	71.2° 09:35	9.56	40%	104.1°
2047-03-04 Mon	24	—	unknown	04:30–05:20 (good, 0.83 h)	71.1° 09:30	9.51	50%	112.9°
2047-03-05 Tue	25	—	unknown	04:25–05:20 (good, 0.92 h)	71.1° 09:30	9.47	60%	121.4°
2047-03-06 Wed	25	—	unknown	04:25–05:15 (good, 0.83 h)	71.1° 09:25	9.42	70%	129.0°
2047-03-07 Thu	26	—	unknown	04:20–05:15 (good, 0.92 h)	71.2° 09:20	9.37	79%	135.2°
2047-03-08 Fri	26	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:15	9.32	87%	138.8°
2047-03-09 Sat	23	—	unknown	04:20–05:10 (good, 0.83 h)	71.1° 09:10	9.28	94%	138.8°
2047-03-10 Sun	24	—	unknown	04:15–05:10 (good, 0.92 h)	71.1° 09:10	9.23	98%	134.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-02-09&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.