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: 04-24 (67), 04-22 (66), 04-23 (66), 04-25 (66), 04-26 (66) — by astronomy; check the weather when the night is within four days.

2045-04-05astronomy score per night — click a bar for that night2045-05-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-05 Wed	27	—	unknown	04:05–05:20 (good, 1.25 h)	71.1° 08:25	7.84	81%	72.2°
2045-04-06 Thu	28	—	unknown	03:45–05:20 (good, 1.58 h)	71.1° 08:20	7.78	72%	64.0°
2045-04-07 Fri	29	—	unknown	03:40–05:15 (good, 1.58 h)	71.1° 08:15	7.73	63%	56.6°
2045-04-08 Sat	33	—	unknown	03:30–05:15 (good, 1.75 h)	71.1° 08:10	7.67	54%	50.6°
2045-04-09 Sun	42	—	unknown	03:05–05:15 (good, 2.17 h)	71.1° 08:10	7.61	44%	46.3°
2045-04-10 Mon	47	—	unknown	03:05–05:10 (good, 2.08 h)	71.1° 08:05	7.56	35%	44.1°
2045-04-11 Tue	52	—	unknown	03:00–05:10 (good, 2.17 h)	71.1° 08:00	7.5	26%	44.4°
2045-04-12 Wed	55	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:55	7.44	18%	47.2°
2045-04-13 Thu	57	—	unknown	02:50–05:05 (good, 2.25 h)	71.1° 07:55	7.39	12%	52.1°
2045-04-14 Fri	59	—	unknown	02:45–05:05 (good, 2.33 h)	71.1° 07:50	7.33	6%	58.7°
2045-04-15 Sat	59	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:45	7.27	2%	66.6°
2045-04-16 Sun	60	—	unknown	02:40–05:00 (good, 2.33 h)	71.1° 07:40	7.21	0%	75.4°
2045-04-17 Mon	60	—	unknown	02:35–04:55 (good, 2.33 h)	71.1° 07:35	7.15	1%	84.8°
2045-04-18 Tue	62	—	unknown	02:30–04:55 (good, 2.42 h)	71.1° 07:35	7.1	3%	94.5°
2045-04-19 Wed	63	—	unknown	02:30–04:55 (good, 2.42 h)	71.1° 07:30	7.04	8%	104.3°
2045-04-20 Thu	64	—	unknown	02:25–04:50 (good, 2.42 h)	71.1° 07:25	6.98	15%	113.7°
2045-04-21 Fri	65	—	unknown	02:20–04:50 (good, 2.5 h)	71.1° 07:20	6.92	24%	122.3°
2045-04-22 Sat	66	—	unknown	02:15–04:50 (good, 2.58 h)	71.1° 07:15	6.86	35%	129.5°
2045-04-23 Sun	66	—	unknown	02:15–04:45 (good, 2.5 h)	71.1° 07:15	6.81	46%	134.4°
2045-04-24 Mon	67	—	unknown	02:15–04:45 (good, 2.5 h)	71.1° 07:10	6.75	57%	136.2°
2045-04-25 Tue	66	—	unknown	02:10–04:40 (good, 2.5 h)	71.1° 07:05	6.69	68%	134.4°
2045-04-26 Wed	66	—	unknown	02:10–04:40 (good, 2.5 h)	71.1° 07:00	6.63	78%	129.4°
2045-04-27 Thu	66	—	unknown	02:05–04:40 (good, 2.58 h)	71.1° 07:00	6.57	87%	122.1°
2045-04-28 Fri	57	—	unknown	02:05–04:35 (good, 2.5 h)	71.1° 06:55	6.51	94%	113.5°
2045-04-29 Sat	51	—	unknown	02:10–04:35 (good, 2.42 h)	71.1° 06:50	6.46	98%	104.1°
2045-04-30 Sun	45	—	unknown	02:10–04:30 (good, 2.33 h)	71.1° 06:45	6.4	100%	94.4°
2045-05-01 Mon	40	—	unknown	02:40–04:30 (good, 1.83 h)	71.1° 06:40	6.34	99%	84.8°
2045-05-02 Tue	37	—	unknown	03:05–04:30 (good, 1.42 h)	71.1° 06:40	6.28	97%	75.5°
2045-05-03 Wed	35	—	unknown	03:20–04:25 (good, 1.08 h)	71.1° 06:35	6.22	92%	66.8°
2045-05-04 Thu	35	—	unknown	03:15–04:25 (good, 1.17 h)	71.1° 06:30	6.17	86%	59.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-05&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.