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: 03-17 (35), 03-16 (34), 03-18 (34), 03-14 (32), 03-15 (32) — by astronomy; check the weather when the night is within four days.

2035-02-17astronomy score per night — click a bar for that night2035-03-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-02-17 Sat	11	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:30	10.17	76%	129.9°
2035-02-18 Sun	12	—	unknown	05:25–05:40 (good, 0.25 h)	71.1° 10:25	10.13	85%	136.9°
2035-02-19 Mon	12	—	unknown	05:30–05:40 (good, 0.17 h)	71.1° 10:25	10.09	92%	140.7°
2035-02-20 Tue	12	—	unknown	05:25–05:40 (good, 0.25 h)	71.1° 10:20	10.05	97%	140.3°
2035-02-21 Wed	12	—	unknown	05:25–05:35 (good, 0.17 h)	71.1° 10:15	10.01	100%	136.0°
2035-02-22 Thu	12	—	unknown	05:20–05:35 (good, 0.25 h)	71.1° 10:10	9.96	100%	128.9°
2035-02-23 Fri	13	—	unknown	05:15–05:35 (good, 0.33 h)	71.1° 10:05	9.92	97%	120.3°
2035-02-24 Sat	13	—	unknown	05:20–05:35 (good, 0.25 h)	71.1° 10:05	9.88	92%	110.9°
2035-02-25 Sun	12	—	unknown	05:20–05:30 (good, 0.17 h)	71.1° 10:00	9.83	86%	101.2°
2035-02-26 Mon	12	—	unknown	05:20–05:30 (good, 0.17 h)	71.1° 09:55	9.79	79%	91.6°
2035-02-27 Tue	12	—	unknown	05:15–05:30 (good, 0.25 h)	71.1° 09:50	9.75	70%	82.1°
2035-02-28 Wed	12	—	unknown	05:10–05:25 (good, 0.25 h)	71.1° 09:45	9.7	61%	73.0°
2035-03-01 Thu	13	—	unknown	05:05–05:25 (good, 0.33 h)	71.1° 09:45	9.66	52%	64.2°
2035-03-02 Fri	15	—	unknown	04:55–05:25 (good, 0.5 h)	71.1° 09:40	9.61	42%	56.1°
2035-03-03 Sat	17	—	unknown	04:45–05:20 (good, 0.58 h)	71.1° 09:35	9.56	33%	48.9°
2035-03-04 Sun	19	—	unknown	04:40–05:20 (good, 0.67 h)	71.1° 09:30	9.52	24%	43.2°
2035-03-05 Mon	22	—	unknown	04:25–05:20 (good, 0.92 h)	71.1° 09:30	9.47	17%	39.6°
2035-03-06 Tue	25	—	unknown	04:25–05:15 (good, 0.83 h)	71.1° 09:25	9.42	10%	39.2°
2035-03-07 Wed	26	—	unknown	04:20–05:15 (good, 0.92 h)	71.1° 09:20	9.38	5%	42.0°
2035-03-08 Thu	27	—	unknown	04:15–05:15 (good, 1.0 h)	71.1° 09:15	9.33	1%	47.8°
2035-03-09 Fri	27	—	unknown	04:10–05:10 (good, 1.0 h)	71.1° 09:10	9.28	0%	55.8°
2035-03-10 Sat	29	—	unknown	04:05–05:10 (good, 1.08 h)	71.1° 09:10	9.23	1%	65.2°
2035-03-11 Sun	30	—	unknown	04:05–05:10 (good, 1.08 h)	71.1° 09:05	9.18	5%	75.6°
2035-03-12 Mon	30	—	unknown	04:00–05:05 (good, 1.08 h)	71.1° 09:00	9.13	11%	86.4°
2035-03-13 Tue	31	—	unknown	03:55–05:05 (good, 1.17 h)	71.1° 08:55	9.09	19%	97.4°
2035-03-14 Wed	32	—	unknown	03:50–05:05 (good, 1.25 h)	71.1° 08:50	9.04	29%	108.3°
2035-03-15 Thu	32	—	unknown	03:45–05:00 (good, 1.25 h)	71.1° 08:50	8.99	40%	118.6°
2035-03-16 Fri	34	—	unknown	03:45–05:00 (good, 1.25 h)	71.1° 08:45	8.94	51%	127.9°
2035-03-17 Sat	35	—	unknown	03:40–05:00 (good, 1.33 h)	71.1° 08:40	8.88	62%	135.4°
2035-03-18 Sun	34	—	unknown	03:35–04:55 (good, 1.33 h)	71.1° 08:35	8.83	73%	140.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-02-17&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.