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 Vega: 09-05 (100), 09-06 (100), 09-07 (100), 09-08 (100), 09-09 (100) — by astronomy; check the weather when the night is within four days.

2039-08-27astronomy score per night — click a bar for that night2039-09-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-08-27 Sat	98	—	unknown	21:45–03:35 (good, 5.83 h)	87.1° 21:35	7.32	61%	65.2°
2039-08-28 Sun	91	—	unknown	21:45–03:30 (good, 5.75 h)	87.1° 21:30	7.38	72%	63.7°
2039-08-29 Mon	84	—	unknown	21:40–03:25 (good, 5.75 h)	87.1° 21:30	7.43	82%	64.0°
2039-08-30 Tue	67	—	unknown	21:40–02:20 (good, 4.67 h)	87.1° 21:25	7.49	90%	66.0°
2039-08-31 Wed	65	—	unknown	21:40–01:00 (good, 3.33 h)	87.1° 21:20	7.55	95%	69.5°
2039-09-01 Thu	66	—	unknown	21:35–00:45 (good, 3.17 h)	87.1° 21:15	7.6	99%	74.1°
2039-09-02 Fri	71	—	unknown	21:35–00:55 (good, 3.33 h)	87.1° 21:10	7.66	100%	79.4°
2039-09-03 Sat	77	—	unknown	21:30–01:20 (good, 3.83 h)	87.1° 21:10	7.71	98%	85.2°
2039-09-04 Sun	81	—	unknown	21:30–01:50 (good, 4.33 h)	87.1° 21:05	7.77	95%	91.0°
2039-09-05 Mon	100	—	unknown	21:30–02:25 (good, 4.92 h)	87.1° 21:00	7.82	89%	96.6°
2039-09-06 Tue	100	—	unknown	21:25–02:30 (good, 5.08 h)	87.1° 20:55	7.88	82%	101.8°
2039-09-07 Wed	100	—	unknown	21:25–02:35 (good, 5.17 h)	87.1° 20:55	7.93	74%	106.5°
2039-09-08 Thu	100	—	unknown	21:20–02:35 (good, 5.25 h)	87.1° 20:50	7.99	65%	110.4°
2039-09-09 Fri	100	—	unknown	21:20–02:35 (good, 5.25 h)	87.1° 20:45	8.04	56%	113.4°
2039-09-10 Sat	100	—	unknown	21:20–02:35 (good, 5.25 h)	87.1° 20:40	8.1	47%	115.4°
2039-09-11 Sun	100	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:35	8.15	37%	116.2°
2039-09-12 Mon	100	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:35	8.2	28%	115.9°
2039-09-13 Tue	100	—	unknown	21:10–02:30 (good, 5.33 h)	87.1° 20:30	8.26	20%	114.3°
2039-09-14 Wed	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:25	8.31	13%	111.5°
2039-09-15 Thu	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:20	8.36	7%	107.6°
2039-09-16 Fri	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.42	3%	102.9°
2039-09-17 Sat	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.47	0%	97.4°
2039-09-18 Sun	100	—	unknown	21:00–02:10 (good, 5.17 h)	87.1° 20:10	8.52	1%	91.4°
2039-09-19 Mon	100	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.57	3%	85.3°
2039-09-20 Tue	100	—	unknown	21:00–02:00 (good, 5.0 h)	87.1° 20:00	8.62	8%	79.3°
2039-09-21 Wed	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 20:00	8.68	16%	73.9°
2039-09-22 Thu	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.73	25%	69.3°
2039-09-23 Fri	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:50	8.78	36%	66.0°
2039-09-24 Sat	94	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.83	47%	64.2°
2039-09-25 Sun	87	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.88	58%	64.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-08-27&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.