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: 07-18 (100), 07-19 (100), 07-20 (100), 07-21 (100), 07-22 (100) — by astronomy; check the weather when the night is within four days.

2041-07-14astronomy score per night — click a bar for that night2041-08-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-07-14 Sun	49	—	unknown	23:00–04:00 (marginal, 5.0 h)	71.1° 01:50	4.97	98%	47.2°
2041-07-15 Mon	57	—	unknown	23:00–00:45 (good, 1.75 h)	71.1° 01:45	5.01	93%	49.1°
2041-07-16 Tue	96	—	unknown	23:00–02:35 (good, 3.58 h)	71.1° 01:45	5.06	86%	54.1°
2041-07-17 Wed	99	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:40	5.1	77%	61.2°
2041-07-18 Thu	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.15	66%	69.7°
2041-07-19 Fri	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:30	5.19	55%	78.8°
2041-07-20 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:25	5.24	44%	88.0°
2041-07-21 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:25	5.29	34%	97.1°
2041-07-22 Mon	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.34	24%	105.7°
2041-07-23 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:15	5.39	16%	113.7°
2041-07-24 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.44	9%	120.8°
2041-07-25 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.49	4%	126.6°
2041-07-26 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.54	1%	130.7°
2041-07-27 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 01:00	5.6	0%	132.7°
2041-07-28 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.65	1%	132.4°
2041-07-29 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:50	5.7	3%	129.9°
2041-07-30 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:50	5.76	8%	125.6°
2041-07-31 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.81	13%	119.8°
2041-08-01 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.87	20%	113.0°
2041-08-02 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.92	28%	105.5°
2041-08-03 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	5.98	38%	97.5°
2041-08-04 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.03	47%	89.2°
2041-08-05 Mon	100	—	unknown	22:25–04:30 (good, 6.08 h)	71.1° 00:25	6.09	57%	80.6°
2041-08-06 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.15	68%	72.1°
2041-08-07 Wed	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:15	6.2	77%	63.8°
2041-08-08 Thu	97	—	unknown	22:20–04:35 (good, 6.25 h)	71.1° 00:15	6.26	86%	56.4°
2041-08-09 Fri	88	—	unknown	00:35–04:40 (good, 4.08 h)	71.1° 00:10	6.32	93%	50.7°
2041-08-10 Sat	56	—	unknown	22:20–04:40 (marginal, 6.33 h)	71.1° 00:05	6.38	98%	47.5°
2041-08-11 Sun	54	—	unknown	22:15–04:40 (marginal, 6.42 h)	71.1° 00:00	6.43	100%	47.8°
2041-08-12 Mon	59	—	unknown	22:15–22:50 (good, 0.58 h)	71.1° 23:55	6.49	99%	51.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-07-14&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.