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.

2035-06-27astronomy score per night — click a bar for that night2035-07-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-06-27 Wed	99	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.47	59%	61.0°
2035-06-28 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	48%	70.3°
2035-06-29 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	38%	80.5°
2035-06-30 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:50	4.51	27%	91.2°
2035-07-01 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.53	17%	102.2°
2035-07-02 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.56	9%	113.1°
2035-07-03 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.58	4%	123.4°
2035-07-04 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.61	0%	132.3°
2035-07-05 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.63	0%	138.4°
2035-07-06 Fri	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.66	4%	140.4°
2035-07-07 Sat	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:20	4.69	9%	137.8°
2035-07-08 Sun	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:15	4.73	17%	131.8°
2035-07-09 Mon	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:10	4.76	26%	123.7°
2035-07-10 Tue	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:10	4.79	36%	114.6°
2035-07-11 Wed	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.83	46%	105.1°
2035-07-12 Thu	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:00	4.87	56%	95.5°
2035-07-13 Fri	100	—	unknown	23:00–03:55 (good, 4.92 h)	71.1° 01:55	4.91	66%	86.1°
2035-07-14 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:55	4.95	75%	76.9°
2035-07-15 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	4.99	82%	68.0°
2035-07-16 Mon	100	—	unknown	23:35–04:00 (good, 4.42 h)	71.1° 01:45	5.03	89%	59.7°
2035-07-17 Tue	60	—	unknown	02:10–04:00 (good, 1.83 h)	71.1° 01:40	5.08	94%	52.2°
2035-07-18 Wed	48	—	unknown	22:55–04:05 (marginal, 5.17 h)	71.1° 01:35	5.12	98%	45.9°
2035-07-19 Thu	38	—	unknown	22:55–04:05 (marginal, 5.17 h)	71.1° 01:35	5.17	100%	41.5°
2035-07-20 Fri	36	—	unknown	22:55–04:05 (marginal, 5.17 h)	71.1° 01:30	5.22	100%	39.7°
2035-07-21 Sat	40	—	unknown	22:50–04:10 (marginal, 5.33 h)	71.1° 01:25	5.26	98%	40.9°
2035-07-22 Sun	49	—	unknown	22:50–04:10 (marginal, 5.33 h)	71.1° 01:20	5.31	94%	44.9°
2035-07-23 Mon	63	—	unknown	22:50–00:55 (good, 2.08 h)	71.1° 01:15	5.36	89%	51.2°
2035-07-24 Tue	98	—	unknown	22:50–03:20 (good, 4.5 h)	71.1° 01:15	5.41	82%	59.1°
2035-07-25 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.46	73%	68.1°
2035-07-26 Thu	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.52	63%	77.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-06-27&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.