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: 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100), 09-05 (100) — by astronomy; check the weather when the night is within four days.

2035-09-01astronomy score per night — click a bar for that night2035-09-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-09-01 Sat	100	—	unknown	21:35–03:45 (good, 6.17 h)	71.1° 22:40	7.6	0%	130.5°
2035-09-02 Sun	100	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:35	7.66	1%	121.9°
2035-09-03 Mon	100	—	unknown	21:30–03:40 (good, 6.17 h)	71.1° 22:30	7.71	4%	112.4°
2035-09-04 Tue	100	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:30	7.77	10%	102.4°
2035-09-05 Wed	100	—	unknown	21:30–03:30 (good, 6.0 h)	71.1° 22:25	7.82	17%	92.5°
2035-09-06 Thu	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.88	25%	82.8°
2035-09-07 Fri	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:15	7.93	34%	73.5°
2035-09-08 Sat	100	—	unknown	21:20–03:20 (good, 6.0 h)	71.1° 22:15	7.99	43%	64.7°
2035-09-09 Sun	98	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:10	8.04	53%	56.6°
2035-09-10 Mon	93	—	unknown	21:20–03:10 (good, 5.83 h)	71.1° 22:05	8.1	62%	49.5°
2035-09-11 Tue	87	—	unknown	21:15–03:05 (good, 5.83 h)	71.1° 22:00	8.15	71%	43.9°
2035-09-12 Wed	72	—	unknown	02:40–03:05 (good, 0.42 h)	71.1° 21:55	8.2	80%	40.4°
2035-09-13 Thu	44	—	unknown	21:10–03:20 (marginal, 6.17 h)	71.1° 21:55	8.26	87%	39.8°
2035-09-14 Fri	39	—	unknown	21:10–03:10 (marginal, 6.0 h)	71.1° 21:50	8.31	93%	42.2°
2035-09-15 Sat	39	—	unknown	21:10–02:55 (marginal, 5.75 h)	71.1° 21:45	8.36	97%	47.3°
2035-09-16 Sun	44	—	unknown	21:05–02:50 (marginal, 5.75 h)	71.1° 21:40	8.42	100%	54.5°
2035-09-17 Mon	53	—	unknown	21:05–22:05 (good, 1.0 h)	71.1° 21:35	8.47	100%	63.2°
2035-09-18 Tue	66	—	unknown	21:00–23:45 (good, 2.75 h)	71.1° 21:35	8.52	98%	72.9°
2035-09-19 Wed	79	—	unknown	21:00–00:50 (good, 3.83 h)	71.1° 21:30	8.57	94%	83.1°
2035-09-20 Thu	100	—	unknown	21:00–01:55 (good, 4.92 h)	71.1° 21:25	8.62	87%	93.7°
2035-09-21 Fri	100	—	unknown	20:55–02:10 (good, 5.25 h)	71.1° 21:20	8.67	79%	104.3°
2035-09-22 Sat	100	—	unknown	20:55–02:15 (good, 5.33 h)	71.1° 21:20	8.73	69%	114.6°
2035-09-23 Sun	100	—	unknown	20:55–02:15 (good, 5.33 h)	71.1° 21:15	8.78	58%	124.2°
2035-09-24 Mon	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.1° 21:10	8.83	46%	132.3°
2035-09-25 Tue	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.1° 21:05	8.88	35%	138.1°
2035-09-26 Wed	100	—	unknown	20:45–02:10 (good, 5.42 h)	71.1° 21:00	8.93	25%	140.3°
2035-09-27 Thu	100	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 21:00	8.98	16%	138.5°
2035-09-28 Fri	100	—	unknown	20:45–02:00 (good, 5.25 h)	71.1° 20:55	9.02	8%	133.1°
2035-09-29 Sat	100	—	unknown	20:40–01:55 (good, 5.25 h)	71.1° 20:50	9.07	3%	125.3°
2035-09-30 Sun	100	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:45	9.12	0%	116.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-09-01&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.