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: 07-31 (100), 08-01 (100), 08-02 (100), 08-03 (100), 08-04 (100) — by astronomy; check the weather when the night is within four days.

2037-07-30astronomy score per night — click a bar for that night2037-08-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2037-08-14 Fri	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:50	6.6	17%	106.4°
2037-08-15 Sat	100	—	unknown	22:10–04:50 (good, 6.67 h)	71.1° 23:45	6.66	27%	95.9°
2037-08-16 Sun	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:40	6.72	38%	85.5°
2037-08-17 Mon	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:35	6.78	49%	75.5°
2037-08-18 Tue	100	—	unknown	22:00–04:40 (good, 6.67 h)	71.1° 23:35	6.83	60%	66.2°
2037-08-19 Wed	99	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.89	70%	57.9°
2037-08-20 Thu	93	—	unknown	22:00–04:30 (good, 6.5 h)	71.1° 23:25	6.95	79%	50.9°
2037-08-21 Fri	87	—	unknown	00:25–04:30 (good, 4.08 h)	71.1° 23:20	7.01	86%	45.8°
2037-08-22 Sat	76	—	unknown	04:00–04:25 (good, 0.42 h)	71.1° 23:15	7.06	92%	43.2°
2037-08-23 Sun	47	—	unknown	21:55–04:35 (marginal, 6.67 h)	71.1° 23:15	7.12	97%	43.3°
2037-08-24 Mon	47	—	unknown	21:50–04:25 (marginal, 6.58 h)	71.1° 23:10	7.18	99%	46.0°
2037-08-25 Tue	51	—	unknown	21:50–04:20 (marginal, 6.5 h)	71.1° 23:05	7.24	100%	50.9°
2037-08-26 Wed	60	—	unknown	21:45–22:50 (good, 1.08 h)	71.1° 23:00	7.29	99%	57.3°
2037-08-27 Thu	71	—	unknown	21:45–00:20 (good, 2.58 h)	71.1° 23:00	7.35	96%	64.7°
2037-08-28 Fri	77	—	unknown	21:45–01:35 (good, 3.83 h)	71.1° 22:55	7.41	91%	72.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-30&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.