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: 04-22 (66), 04-24 (66), 04-21 (65), 04-23 (65), 04-20 (64) — by astronomy; check the weather when the night is within four days.

2037-03-26astronomy score per night — click a bar for that night2037-04-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-03-26 Thu	40	—	unknown	03:10–04:40 (good, 1.5 h)	71.1° 08:05	8.39	73%	137.8°
2037-03-27 Fri	40	—	unknown	03:05–04:40 (good, 1.58 h)	71.1° 08:00	8.34	83%	135.7°
2037-03-28 Sat	36	—	unknown	04:05–05:35 (good, 1.5 h)	71.1° 08:55	8.28	91%	130.0°
2037-03-29 Sun	36	—	unknown	04:00–05:35 (good, 1.58 h)	71.1° 08:50	8.23	97%	121.8°
2037-03-30 Mon	33	—	unknown	04:05–05:35 (good, 1.5 h)	71.1° 08:50	8.17	100%	111.9°
2037-03-31 Tue	28	—	unknown	04:05–05:30 (good, 1.42 h)	71.1° 08:45	8.12	99%	101.2°
2037-04-01 Wed	25	—	unknown	04:35–05:30 (good, 0.92 h)	71.1° 08:40	8.06	96%	90.3°
2037-04-02 Thu	23	—	unknown	05:00–05:25 (good, 0.42 h)	71.1° 08:35	8.01	91%	79.7°
2037-04-03 Fri	22	—	unknown	05:10–05:25 (good, 0.25 h)	71.1° 08:30	7.95	84%	69.8°
2037-04-04 Sat	23	—	unknown	05:00–05:25 (good, 0.42 h)	71.1° 08:30	7.9	75%	60.7°
2037-04-05 Sun	25	—	unknown	04:15–05:20 (good, 1.08 h)	71.1° 08:25	7.84	65%	53.0°
2037-04-06 Mon	29	—	unknown	03:40–05:20 (good, 1.67 h)	71.1° 08:20	7.79	55%	47.1°
2037-04-07 Tue	34	—	unknown	03:30–05:15 (good, 1.75 h)	71.1° 08:15	7.73	46%	43.4°
2037-04-08 Wed	43	—	unknown	03:10–05:15 (good, 2.08 h)	71.1° 08:10	7.67	36%	42.3°
2037-04-09 Thu	50	—	unknown	03:05–05:15 (good, 2.17 h)	71.1° 08:10	7.62	27%	44.0°
2037-04-10 Fri	53	—	unknown	03:05–05:10 (good, 2.08 h)	71.1° 08:05	7.56	19%	48.0°
2037-04-11 Sat	56	—	unknown	03:00–05:10 (good, 2.17 h)	71.1° 08:00	7.5	12%	53.8°
2037-04-12 Sun	56	—	unknown	02:55–05:05 (good, 2.17 h)	71.1° 07:55	7.45	7%	60.9°
2037-04-13 Mon	57	—	unknown	02:50–05:05 (good, 2.25 h)	71.1° 07:55	7.39	3%	68.8°
2037-04-14 Tue	59	—	unknown	02:45–05:05 (good, 2.33 h)	71.1° 07:50	7.33	1%	77.4°
2037-04-15 Wed	59	—	unknown	02:45–05:00 (good, 2.25 h)	71.1° 07:45	7.27	0%	86.3°
2037-04-16 Thu	60	—	unknown	02:40–05:00 (good, 2.33 h)	71.1° 07:40	7.22	2%	95.5°
2037-04-17 Fri	60	—	unknown	02:35–04:55 (good, 2.33 h)	71.1° 07:35	7.16	5%	104.7°
2037-04-18 Sat	62	—	unknown	02:30–04:55 (good, 2.42 h)	71.1° 07:35	7.1	11%	113.6°
2037-04-19 Sun	63	—	unknown	02:30–04:55 (good, 2.42 h)	71.1° 07:30	7.04	18%	122.0°
2037-04-20 Mon	64	—	unknown	02:25–04:50 (good, 2.42 h)	71.1° 07:25	6.98	27%	129.3°
2037-04-21 Tue	65	—	unknown	02:20–04:50 (good, 2.5 h)	71.1° 07:20	6.93	37%	134.8°
2037-04-22 Wed	66	—	unknown	02:20–04:50 (good, 2.5 h)	71.1° 07:15	6.87	48%	137.4°
2037-04-23 Thu	65	—	unknown	02:15–04:45 (good, 2.5 h)	71.1° 07:15	6.81	59%	136.5°
2037-04-24 Fri	66	—	unknown	02:15–04:45 (good, 2.5 h)	71.1° 07:10	6.75	70%	132.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-03-26&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.