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: 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100) — by astronomy; check the weather when the night is within four days.

2034-08-17astronomy score per night — click a bar for that night2034-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-08-17 Thu	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:40	6.76	15%	109.9°
2034-08-18 Fri	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.82	22%	100.5°
2034-08-19 Sat	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.88	31%	91.2°
2034-08-20 Sun	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:25	6.93	40%	81.8°
2034-08-21 Mon	100	—	unknown	21:55–04:30 (good, 6.58 h)	71.1° 23:20	6.99	49%	72.7°
2034-08-22 Tue	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:20	7.05	58%	63.9°
2034-08-23 Wed	98	—	unknown	21:55–04:20 (good, 6.42 h)	71.1° 23:15	7.11	68%	55.6°
2034-08-24 Thu	91	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.16	77%	48.1°
2034-08-25 Fri	84	—	unknown	03:10–04:15 (good, 1.08 h)	71.1° 23:05	7.22	84%	42.2°
2034-08-26 Sat	56	—	unknown	04:05–04:10 (good, 0.08 h)	71.1° 23:05	7.28	91%	38.8°
2034-08-27 Sun	38	—	unknown	21:45–04:20 (marginal, 6.58 h)	71.1° 23:00	7.33	96%	38.8°
2034-08-28 Mon	39	—	unknown	21:45–04:05 (marginal, 6.33 h)	71.1° 22:55	7.39	99%	42.5°
2034-08-29 Tue	45	—	unknown	21:40–03:55 (marginal, 6.25 h)	71.1° 22:50	7.45	100%	49.4°
2034-08-30 Wed	56	—	unknown	21:40–22:30 (good, 0.83 h)	71.1° 22:45	7.5	98%	58.3°
2034-08-31 Thu	73	—	unknown	21:35–00:45 (good, 3.17 h)	71.1° 22:45	7.56	94%	68.5°
2034-09-01 Fri	100	—	unknown	21:35–02:00 (good, 4.42 h)	71.1° 22:40	7.61	87%	79.4°
2034-09-02 Sat	100	—	unknown	21:35–03:10 (good, 5.58 h)	71.1° 22:35	7.67	78%	90.7°
2034-09-03 Sun	100	—	unknown	21:30–03:20 (good, 5.83 h)	71.1° 22:30	7.73	68%	101.9°
2034-09-04 Mon	100	—	unknown	21:30–03:25 (good, 5.92 h)	71.1° 22:25	7.78	56%	112.7°
2034-09-05 Tue	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:25	7.84	45%	122.7°
2034-09-06 Wed	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.89	34%	131.5°
2034-09-07 Thu	100	—	unknown	21:25–03:20 (good, 5.92 h)	71.1° 22:15	7.95	24%	138.0°
2034-09-08 Fri	100	—	unknown	21:20–03:20 (good, 6.0 h)	71.1° 22:10	8.0	15%	141.4°
2034-09-09 Sat	100	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:10	8.05	8%	140.9°
2034-09-10 Sun	100	—	unknown	21:15–03:10 (good, 5.92 h)	71.1° 22:05	8.11	3%	136.8°
2034-09-11 Mon	100	—	unknown	21:15–03:05 (good, 5.83 h)	71.1° 22:00	8.16	1%	130.2°
2034-09-12 Tue	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.1° 21:55	8.22	0%	122.0°
2034-09-13 Wed	100	—	unknown	21:10–03:00 (good, 5.83 h)	71.1° 21:50	8.27	2%	113.1°
2034-09-14 Thu	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:50	8.32	5%	103.7°
2034-09-15 Fri	100	—	unknown	21:10–02:50 (good, 5.67 h)	71.1° 21:45	8.38	10%	94.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-08-17&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.