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: 06-28 (100), 06-29 (100), 06-30 (100), 07-01 (100), 07-02 (100) — by astronomy; check the weather when the night is within four days.

2047-06-28astronomy score per night — click a bar for that night2047-07-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-06-28 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.2° 02:55	4.48	30%	131.1°
2047-06-29 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	41%	122.9°
2047-06-30 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:50	4.52	52%	113.4°
2047-07-01 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.2° 02:45	4.54	64%	102.9°
2047-07-02 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.2° 02:40	4.56	74%	92.0°
2047-07-03 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.2° 02:35	4.58	84%	80.9°
2047-07-04 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.61	92%	70.1°
2047-07-05 Fri	61	—	unknown	00:25–03:45 (good, 3.33 h)	71.1° 02:30	4.64	97%	59.9°
2047-07-06 Sat	47	—	unknown	23:10–04:40 (marginal, 5.5 h)	71.2° 02:25	4.67	100%	51.0°
2047-07-07 Sun	38	—	unknown	23:10–03:50 (marginal, 4.67 h)	71.2° 02:20	4.7	100%	44.2°
2047-07-08 Mon	37	—	unknown	23:05–03:50 (marginal, 4.75 h)	71.1° 02:15	4.73	97%	40.4°
2047-07-09 Tue	42	—	unknown	23:05–03:50 (marginal, 4.75 h)	71.1° 02:15	4.76	92%	40.4°
2047-07-10 Wed	53	—	unknown	23:05–00:40 (good, 1.58 h)	71.1° 02:10	4.8	86%	43.7°
2047-07-11 Thu	88	—	unknown	23:05–02:25 (good, 3.33 h)	71.2° 02:05	4.83	78%	49.6°
2047-07-12 Fri	96	—	unknown	23:05–03:55 (good, 4.83 h)	71.2° 02:00	4.87	70%	56.9°
2047-07-13 Sat	98	—	unknown	23:00–03:55 (good, 4.92 h)	71.1° 01:55	4.91	60%	65.1°
2047-07-14 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:55	4.95	51%	73.8°
2047-07-15 Mon	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.2° 01:50	5.0	41%	82.8°
2047-07-16 Tue	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.2° 01:45	5.04	32%	91.8°
2047-07-17 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.2° 01:40	5.08	24%	100.9°
2047-07-18 Thu	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.13	16%	109.9°
2047-07-19 Fri	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.17	9%	118.6°
2047-07-20 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.2° 01:30	5.22	4%	126.7°
2047-07-21 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.2° 01:25	5.27	1%	133.5°
2047-07-22 Mon	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.32	0%	138.3°
2047-07-23 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.37	1%	140.0°
2047-07-24 Wed	100	—	unknown	22:50–04:15 (good, 5.42 h)	71.1° 01:15	5.42	5%	138.1°
2047-07-25 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.2° 01:10	5.47	10%	132.7°
2047-07-26 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.2° 01:05	5.52	18%	124.9°
2047-07-27 Sat	100	—	unknown	22:45–04:20 (good, 5.58 h)	71.1° 01:00	5.57	28%	115.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-06-28&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.