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: 06-29 (100), 06-30 (100), 07-01 (100), 07-02 (100), 07-03 (100) — by astronomy; check the weather when the night is within four days.

2043-06-27astronomy score per night — click a bar for that night2043-07-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-06-27 Sat	94	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.47	73%	51.9°
2043-06-28 Sun	97	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	63%	58.2°
2043-06-29 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	52%	66.0°
2043-06-30 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:50	4.51	41%	75.0°
2043-07-01 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.53	30%	84.6°
2043-07-02 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.56	20%	94.6°
2043-07-03 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.58	11%	104.6°
2043-07-04 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.61	5%	114.2°
2043-07-05 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.63	1%	122.6°
2043-07-06 Mon	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.66	0%	129.1°
2043-07-07 Tue	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:20	4.69	2%	133.0°
2043-07-08 Wed	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:15	4.73	6%	133.7°
2043-07-09 Thu	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:15	4.76	13%	131.3°
2043-07-10 Fri	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:10	4.8	21%	126.5°
2043-07-11 Sat	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.83	30%	120.1°
2043-07-12 Sun	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:00	4.87	39%	112.8°
2043-07-13 Mon	100	—	unknown	23:00–03:55 (good, 4.92 h)	71.1° 01:55	4.91	49%	104.9°
2043-07-14 Tue	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:55	4.95	58%	96.8°
2043-07-15 Wed	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	4.99	67%	88.6°
2043-07-16 Thu	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.04	76%	80.4°
2043-07-17 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:40	5.08	84%	72.5°
2043-07-18 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.13	90%	64.9°
2043-07-19 Sun	98	—	unknown	23:10–04:05 (good, 4.92 h)	71.1° 01:35	5.17	95%	58.0°
2043-07-20 Mon	59	—	unknown	02:20–04:05 (good, 1.75 h)	71.1° 01:30	5.22	98%	52.2°
2043-07-21 Tue	49	—	unknown	22:50–04:10 (marginal, 5.33 h)	71.1° 01:25	5.27	100%	48.0°
2043-07-22 Wed	48	—	unknown	22:50–04:10 (marginal, 5.33 h)	71.1° 01:20	5.32	99%	46.2°
2043-07-23 Thu	51	—	unknown	22:50–23:25 (good, 0.58 h)	71.1° 01:15	5.37	96%	47.0°
2043-07-24 Fri	61	—	unknown	22:50–00:30 (good, 1.67 h)	71.1° 01:15	5.42	92%	50.6°
2043-07-25 Sat	97	—	unknown	22:45–02:15 (good, 3.5 h)	71.1° 01:10	5.47	85%	56.5°
2043-07-26 Sun	100	—	unknown	22:45–03:50 (good, 5.08 h)	71.1° 01:05	5.52	76%	64.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-06-27&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.