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: 07-15 (100), 07-16 (100), 07-17 (100), 07-18 (100), 07-19 (100) — by astronomy; check the weather when the night is within four days.

2037-07-15astronomy score per night — click a bar for that night2037-08-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-07-15 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.01	11%	130.2°
2037-07-16 Thu	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.06	19%	122.4°
2037-07-17 Fri	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:40	5.1	29%	113.2°
2037-07-18 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.15	40%	103.3°
2037-07-19 Sun	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:30	5.19	52%	93.1°
2037-07-20 Mon	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:25	5.24	63%	83.0°
2037-07-21 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:25	5.29	73%	73.2°
2037-07-22 Wed	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.34	82%	64.2°
2037-07-23 Thu	97	—	unknown	23:25–04:10 (good, 4.75 h)	71.1° 01:15	5.39	90%	56.1°
2037-07-24 Fri	60	—	unknown	02:25–04:15 (good, 1.83 h)	71.1° 01:10	5.44	95%	49.4°
2037-07-25 Sat	48	—	unknown	22:45–04:15 (marginal, 5.5 h)	71.1° 01:10	5.49	98%	44.9°
2037-07-26 Sun	42	—	unknown	22:45–04:15 (marginal, 5.5 h)	71.1° 01:05	5.54	100%	42.9°
2037-07-27 Mon	45	—	unknown	22:40–04:20 (marginal, 5.67 h)	71.1° 01:00	5.6	99%	43.8°
2037-07-28 Tue	53	—	unknown	22:40–23:05 (good, 0.42 h)	71.1° 00:55	5.65	97%	47.2°
2037-07-29 Wed	64	—	unknown	22:40–00:25 (good, 1.75 h)	71.1° 00:50	5.7	93%	52.6°
2037-07-30 Thu	98	—	unknown	22:35–02:25 (good, 3.83 h)	71.1° 00:50	5.76	87%	59.3°
2037-07-31 Fri	100	—	unknown	22:35–03:40 (good, 5.08 h)	71.1° 00:45	5.81	80%	67.0°
2037-08-01 Sat	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.87	72%	75.2°
2037-08-02 Sun	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.92	63%	83.8°
2037-08-03 Mon	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	5.98	54%	92.6°
2037-08-04 Tue	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.03	44%	101.5°
2037-08-05 Wed	100	—	unknown	22:25–04:30 (good, 6.08 h)	71.1° 00:25	6.09	34%	110.4°
2037-08-06 Thu	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.15	25%	119.0°
2037-08-07 Fri	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:15	6.2	16%	126.8°
2037-08-08 Sat	100	—	unknown	22:20–04:35 (good, 6.25 h)	71.1° 00:15	6.26	9%	133.1°
2037-08-09 Sun	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:10	6.32	3%	136.7°
2037-08-10 Mon	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:05	6.37	0%	136.6°
2037-08-11 Tue	100	—	unknown	22:15–04:40 (good, 6.42 h)	71.1° 00:00	6.43	0%	132.6°
2037-08-12 Wed	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 23:55	6.49	3%	125.5°
2037-08-13 Thu	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:55	6.55	9%	116.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-15&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.