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: 05-31 (100), 06-01 (100), 06-02 (100), 06-03 (100), 06-04 (100) — by astronomy; check the weather when the night is within four days.

2035-05-11astronomy score per night — click a bar for that night2035-06-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-05-11 Fri	86	—	unknown	01:05–04:15 (good, 3.17 h)	71.1° 06:05	5.81	23%	137.8°
2035-05-12 Sat	87	—	unknown	01:00–04:10 (good, 3.17 h)	71.1° 06:00	5.75	33%	140.7°
2035-05-13 Sun	87	—	unknown	01:00–04:10 (good, 3.17 h)	71.1° 05:55	5.7	44%	139.4°
2035-05-14 Mon	88	—	unknown	00:55–04:10 (good, 3.25 h)	71.1° 05:55	5.64	55%	134.6°
2035-05-15 Tue	86	—	unknown	00:55–04:05 (good, 3.17 h)	71.1° 05:50	5.59	66%	127.5°
2035-05-16 Wed	86	—	unknown	00:50–04:05 (good, 3.25 h)	71.1° 05:45	5.53	75%	119.1°
2035-05-17 Thu	75	—	unknown	00:55–04:05 (good, 3.17 h)	71.1° 05:40	5.48	83%	110.0°
2035-05-18 Fri	66	—	unknown	00:55–04:05 (good, 3.17 h)	71.1° 05:35	5.43	90%	100.6°
2035-05-19 Sat	56	—	unknown	01:20–04:00 (good, 2.67 h)	71.1° 05:35	5.38	95%	91.1°
2035-05-20 Sun	48	—	unknown	02:05–04:00 (good, 1.92 h)	71.1° 05:30	5.33	98%	81.7°
2035-05-21 Mon	41	—	unknown	02:50–04:00 (good, 1.17 h)	71.1° 05:25	5.28	100%	72.6°
2035-05-22 Tue	35	—	unknown	03:40–03:55 (good, 0.25 h)	71.1° 05:20	5.23	99%	63.9°
2035-05-23 Wed	32	—	unknown	00:00–03:55 (marginal, 3.92 h)	71.1° 05:15	5.18	97%	55.9°
2035-05-24 Thu	31	—	unknown	23:55–03:55 (marginal, 4.0 h)	71.1° 05:15	5.14	93%	48.8°
2035-05-25 Fri	32	—	unknown	23:45–03:55 (marginal, 4.17 h)	71.1° 05:10	5.09	88%	43.3°
2035-05-26 Sat	41	—	unknown	00:05–00:10 (good, 0.08 h)	71.1° 05:05	5.05	81%	40.1°
2035-05-27 Sun	62	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:00	5.0	73%	39.6°
2035-05-28 Mon	75	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 05:00	4.96	64%	42.1°
2035-05-29 Tue	86	—	unknown	23:50–03:50 (good, 4.0 h)	71.1° 04:55	4.92	54%	47.4°
2035-05-30 Wed	96	—	unknown	23:50–03:45 (good, 3.92 h)	71.1° 04:50	4.88	44%	54.7°
2035-05-31 Thu	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.84	33%	63.5°
2035-06-01 Fri	100	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:40	4.8	24%	73.4°
2035-06-02 Sat	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:40	4.77	15%	84.1°
2035-06-03 Sun	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:35	4.73	7%	95.3°
2035-06-04 Mon	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:30	4.7	2%	106.7°
2035-06-05 Tue	100	—	unknown	23:25–03:40 (good, 4.25 h)	71.1° 04:25	4.67	0%	117.7°
2035-06-06 Wed	100	—	unknown	23:20–03:40 (good, 4.33 h)	71.1° 04:20	4.64	1%	127.6°
2035-06-07 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:20	4.61	5%	135.4°
2035-06-08 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 04:15	4.59	12%	139.9°
2035-06-09 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:10	4.56	20%	140.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-11&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.