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: 05-24 (100), 05-25 (100), 05-26 (100), 05-27 (100), 05-28 (100) — by astronomy; check the weather when the night is within four days.

2033-05-15astronomy score per night — click a bar for that night2033-06-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-05-15 Sun	32	—	unknown	04:00–04:05 (good, 0.08 h)	71.1° 05:45	5.56	98%	62.6°
2033-05-16 Mon	30	—	unknown	00:25–04:05 (marginal, 3.67 h)	71.1° 05:45	5.51	94%	53.6°
2033-05-17 Tue	30	—	unknown	00:20–04:05 (marginal, 3.75 h)	71.1° 05:40	5.46	87%	45.7°
2033-05-18 Wed	34	—	unknown	00:05–04:00 (marginal, 3.92 h)	71.1° 05:35	5.41	80%	39.9°
2033-05-19 Thu	52	—	unknown	01:35–04:00 (good, 2.42 h)	71.1° 05:30	5.35	70%	37.3°
2033-05-20 Fri	66	—	unknown	00:25–04:00 (good, 3.58 h)	71.1° 05:25	5.3	60%	38.8°
2033-05-21 Sat	78	—	unknown	00:20–04:00 (good, 3.67 h)	71.1° 05:25	5.26	48%	44.1°
2033-05-22 Sun	88	—	unknown	00:20–03:55 (good, 3.58 h)	71.1° 05:20	5.21	37%	52.3°
2033-05-23 Mon	97	—	unknown	00:15–03:55 (good, 3.67 h)	71.1° 05:15	5.16	26%	62.2°
2033-05-24 Tue	100	—	unknown	00:10–03:55 (good, 3.75 h)	71.1° 05:10	5.11	16%	73.2°
2033-05-25 Wed	100	—	unknown	00:05–03:55 (good, 3.83 h)	71.1° 05:05	5.07	9%	84.6°
2033-05-26 Thu	100	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:05	5.02	3%	96.2°
2033-05-27 Fri	100	—	unknown	00:00–03:50 (good, 3.83 h)	71.1° 05:00	4.98	0%	107.5°
2033-05-28 Sat	100	—	unknown	23:55–03:50 (good, 3.92 h)	71.1° 04:55	4.94	0%	118.2°
2033-05-29 Sun	100	—	unknown	23:50–03:50 (good, 4.0 h)	71.1° 04:50	4.9	3%	127.8°
2033-05-30 Mon	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:50	4.86	8%	135.6°
2033-05-31 Tue	100	—	unknown	23:45–03:45 (good, 4.0 h)	71.1° 04:45	4.82	14%	140.8°
2033-06-01 Wed	100	—	unknown	23:40–03:45 (good, 4.08 h)	71.1° 04:40	4.79	22%	142.7°
2033-06-02 Thu	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:35	4.75	31%	141.0°
2033-06-03 Fri	100	—	unknown	23:35–03:45 (good, 4.17 h)	71.1° 04:30	4.72	40%	136.4°
2033-06-04 Sat	100	—	unknown	23:30–03:45 (good, 4.25 h)	71.1° 04:30	4.68	50%	129.8°
2033-06-05 Sun	100	—	unknown	23:30–03:40 (good, 4.17 h)	71.1° 04:25	4.65	59%	121.9°
2033-06-06 Mon	100	—	unknown	23:30–03:40 (good, 4.17 h)	71.1° 04:20	4.63	68%	113.3°
2033-06-07 Tue	100	—	unknown	23:30–03:40 (good, 4.17 h)	71.1° 04:15	4.6	76%	104.1°
2033-06-08 Wed	99	—	unknown	23:35–03:40 (good, 4.08 h)	71.1° 04:10	4.57	84%	94.7°
2033-06-09 Thu	74	—	unknown	00:05–03:40 (good, 3.58 h)	71.1° 04:10	4.55	91%	85.0°
2033-06-10 Fri	61	—	unknown	00:55–03:40 (good, 2.75 h)	71.1° 04:05	4.53	96%	75.2°
2033-06-11 Sat	49	—	unknown	01:55–03:40 (good, 1.75 h)	71.1° 04:00	4.51	99%	65.5°
2033-06-12 Sun	40	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:55	4.49	100%	56.2°
2033-06-13 Mon	34	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:55	4.48	99%	47.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-05-15&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.