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: 08-20 (100), 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100) — by astronomy; check the weather when the night is within four days.

2045-08-20astronomy score per night — click a bar for that night2045-09-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-08-20 Sun	100	—	unknown	22:00–04:00 (good, 6.0 h)	87.1° 22:00	6.95	64%	70.6°
2045-08-21 Mon	96	—	unknown	21:55–03:55 (good, 6.0 h)	87.1° 22:00	7.01	74%	67.5°
2045-08-22 Tue	88	—	unknown	21:55–03:55 (good, 6.0 h)	87.1° 21:55	7.07	82%	65.5°
2045-08-23 Wed	81	—	unknown	21:55–03:50 (good, 5.92 h)	87.1° 21:50	7.13	88%	64.7°
2045-08-24 Thu	64	—	unknown	21:50–01:25 (good, 3.58 h)	87.1° 21:45	7.18	94%	65.0°
2045-08-25 Fri	61	—	unknown	21:50–00:25 (good, 2.58 h)	87.1° 21:40	7.24	98%	66.4°
2045-08-26 Sat	60	—	unknown	21:45–23:40 (good, 1.92 h)	87.1° 21:40	7.3	100%	68.9°
2045-08-27 Sun	62	—	unknown	21:45–00:15 (good, 2.5 h)	87.1° 21:35	7.35	100%	72.3°
2045-08-28 Mon	68	—	unknown	21:45–00:35 (good, 2.83 h)	87.1° 21:30	7.41	98%	76.4°
2045-08-29 Tue	75	—	unknown	21:40–01:05 (good, 3.42 h)	87.1° 21:25	7.47	95%	81.1°
2045-08-30 Wed	80	—	unknown	21:40–01:45 (good, 4.08 h)	87.1° 21:20	7.52	90%	86.1°
2045-08-31 Thu	84	—	unknown	21:35–02:25 (good, 4.83 h)	87.1° 21:20	7.58	83%	91.4°
2045-09-01 Fri	100	—	unknown	21:35–02:50 (good, 5.25 h)	87.1° 21:15	7.63	75%	96.7°
2045-09-02 Sat	100	—	unknown	21:35–02:50 (good, 5.25 h)	87.1° 21:10	7.69	66%	101.8°
2045-09-03 Sun	100	—	unknown	21:30–02:55 (good, 5.42 h)	87.1° 21:05	7.74	55%	106.6°
2045-09-04 Mon	100	—	unknown	21:30–02:55 (good, 5.42 h)	87.1° 21:00	7.8	44%	110.6°
2045-09-05 Tue	100	—	unknown	21:25–02:55 (good, 5.5 h)	87.1° 21:00	7.86	34%	113.6°
2045-09-06 Wed	100	—	unknown	21:25–02:50 (good, 5.42 h)	87.1° 20:55	7.91	23%	115.2°
2045-09-07 Thu	100	—	unknown	21:25–02:50 (good, 5.42 h)	87.1° 20:50	7.96	14%	115.1°
2045-09-08 Fri	100	—	unknown	21:20–02:45 (good, 5.42 h)	87.1° 20:45	8.02	7%	113.3°
2045-09-09 Sat	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:45	8.07	2%	109.8°
2045-09-10 Sun	100	—	unknown	21:15–02:40 (good, 5.42 h)	87.1° 20:40	8.13	0%	105.0°
2045-09-11 Mon	100	—	unknown	21:15–02:35 (good, 5.33 h)	87.1° 20:35	8.18	1%	99.3°
2045-09-12 Tue	100	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:30	8.23	5%	93.2°
2045-09-13 Wed	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:25	8.29	11%	87.0°
2045-09-14 Thu	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:25	8.34	20%	81.2°
2045-09-15 Fri	100	—	unknown	21:05–02:20 (good, 5.25 h)	87.1° 20:20	8.39	29%	76.0°
2045-09-16 Sat	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.45	39%	71.6°
2045-09-17 Sun	98	—	unknown	21:05–02:10 (good, 5.08 h)	87.1° 20:10	8.5	49%	68.2°
2045-09-18 Mon	91	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.55	58%	65.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-08-20&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.