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: 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100), 08-22 (100) — by astronomy; check the weather when the night is within four days.

2038-08-13astronomy score per night — click a bar for that night2038-09-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-08-13 Fri	49	—	unknown	22:15–04:45 (marginal, 6.5 h)	71.1° 23:55	6.53	99%	44.7°
2038-08-14 Sat	52	—	unknown	22:10–04:45 (marginal, 6.58 h)	71.1° 23:50	6.59	100%	47.2°
2038-08-15 Sun	58	—	unknown	22:10–22:40 (good, 0.5 h)	71.1° 23:45	6.65	99%	52.1°
2038-08-16 Mon	69	—	unknown	22:05–00:00 (good, 1.92 h)	71.1° 23:40	6.7	96%	58.6°
2038-08-17 Tue	75	—	unknown	22:05–01:45 (good, 3.67 h)	71.1° 23:40	6.76	91%	66.1°
2038-08-18 Wed	100	—	unknown	22:05–02:45 (good, 4.67 h)	71.1° 23:35	6.82	85%	74.1°
2038-08-19 Thu	100	—	unknown	22:00–03:35 (good, 5.58 h)	71.1° 23:30	6.88	77%	82.5°
2038-08-20 Fri	100	—	unknown	22:00–04:10 (good, 6.17 h)	71.1° 23:25	6.94	69%	90.9°
2038-08-21 Sat	100	—	unknown	21:55–04:15 (good, 6.33 h)	71.1° 23:20	6.99	60%	99.3°
2038-08-22 Sun	100	—	unknown	21:55–04:15 (good, 6.33 h)	71.1° 23:20	7.05	50%	107.5°
2038-08-23 Mon	100	—	unknown	21:55–04:15 (good, 6.33 h)	71.1° 23:15	7.11	41%	115.4°
2038-08-24 Tue	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.16	31%	122.7°
2038-08-25 Wed	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.22	22%	128.9°
2038-08-26 Thu	100	—	unknown	21:45–04:10 (good, 6.42 h)	71.1° 23:05	7.28	14%	133.4°
2038-08-27 Fri	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.33	8%	135.4°
2038-08-28 Sat	100	—	unknown	21:45–04:00 (good, 6.25 h)	71.1° 22:55	7.39	3%	134.3°
2038-08-29 Sun	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.45	0%	130.0°
2038-08-30 Mon	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:45	7.5	0%	123.1°
2038-08-31 Tue	100	—	unknown	21:35–03:50 (good, 6.25 h)	71.1° 22:45	7.56	3%	114.4°
2038-09-01 Wed	100	—	unknown	21:35–03:45 (good, 6.17 h)	71.1° 22:40	7.62	9%	104.6°
2038-09-02 Thu	100	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:35	7.67	17%	94.3°
2038-09-03 Fri	100	—	unknown	21:30–03:40 (good, 6.17 h)	71.1° 22:30	7.73	26%	84.0°
2038-09-04 Sat	100	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:25	7.78	37%	74.0°
2038-09-05 Sun	100	—	unknown	21:25–03:30 (good, 6.08 h)	71.1° 22:25	7.84	48%	64.7°
2038-09-06 Mon	98	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.89	60%	56.5°
2038-09-07 Tue	91	—	unknown	21:25–03:20 (good, 5.92 h)	71.1° 22:15	7.95	70%	50.0°
2038-09-08 Wed	84	—	unknown	21:20–03:20 (good, 6.0 h)	71.1° 22:10	8.0	79%	45.9°
2038-09-09 Thu	53	—	unknown	21:20–03:40 (marginal, 6.33 h)	71.1° 22:10	8.06	87%	44.6°
2038-09-10 Fri	47	—	unknown	21:15–03:25 (marginal, 6.17 h)	71.1° 22:05	8.11	93%	46.2°
2038-09-11 Sat	47	—	unknown	21:15–03:15 (marginal, 6.0 h)	71.1° 22:00	8.16	97%	50.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-08-13&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.