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: 07-27 (100), 07-28 (100), 07-29 (100), 07-30 (100), 08-10 (100) — by astronomy; check the weather when the night is within four days.

2028-07-27astronomy score per night — click a bar for that night2028-08-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-27 Thu	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:35	5.6	41%	90.1°
2028-07-28 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:30	5.66	52%	83.6°
2028-07-29 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:25	5.71	63%	77.6°
2028-07-30 Sun	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:25	5.77	73%	72.3°
2028-07-31 Mon	99	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:20	5.82	82%	67.8°
2028-08-01 Tue	91	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:15	5.88	89%	64.6°
2028-08-02 Wed	84	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:10	5.93	94%	62.6°
2028-08-03 Thu	62	—	unknown	22:30–23:25 (good, 0.92 h)	87.1° 23:05	5.99	98%	62.0°
2028-08-04 Fri	60	—	unknown	22:30–23:10 (good, 0.67 h)	87.1° 23:05	6.04	100%	62.9°
2028-08-05 Sat	62	—	unknown	22:25–23:40 (good, 1.25 h)	87.1° 23:00	6.1	100%	65.0°
2028-08-06 Sun	67	—	unknown	22:25–00:35 (good, 2.17 h)	87.1° 22:55	6.16	98%	68.1°
2028-08-07 Mon	72	—	unknown	22:25–01:45 (good, 3.33 h)	87.1° 22:50	6.21	94%	72.2°
2028-08-08 Tue	77	—	unknown	22:20–02:25 (good, 4.08 h)	87.1° 22:50	6.27	88%	76.9°
2028-08-09 Wed	81	—	unknown	22:20–03:10 (good, 4.83 h)	87.1° 22:45	6.33	82%	82.1°
2028-08-10 Thu	100	—	unknown	22:15–03:55 (good, 5.67 h)	87.1° 22:40	6.38	74%	87.6°
2028-08-11 Fri	100	—	unknown	22:15–04:10 (good, 5.92 h)	87.1° 22:35	6.44	65%	93.3°
2028-08-12 Sat	100	—	unknown	22:15–04:15 (good, 6.0 h)	87.1° 22:30	6.5	56%	98.9°
2028-08-13 Sun	100	—	unknown	22:10–04:15 (good, 6.08 h)	87.1° 22:30	6.56	46%	104.3°
2028-08-14 Mon	100	—	unknown	22:10–04:15 (good, 6.08 h)	87.1° 22:25	6.61	35%	109.2°
2028-08-15 Tue	100	—	unknown	22:10–04:15 (good, 6.08 h)	87.1° 22:20	6.67	26%	113.4°
2028-08-16 Wed	100	—	unknown	22:05–04:15 (good, 6.17 h)	87.1° 22:15	6.73	16%	116.4°
2028-08-17 Thu	100	—	unknown	22:05–04:10 (good, 6.08 h)	87.1° 22:10	6.79	9%	117.9°
2028-08-18 Fri	100	—	unknown	22:00–04:10 (good, 6.17 h)	87.1° 22:10	6.84	3%	117.5°
2028-08-19 Sat	100	—	unknown	22:00–04:05 (good, 6.08 h)	87.1° 22:05	6.9	0%	115.1°
2028-08-20 Sun	100	—	unknown	22:00–04:00 (good, 6.0 h)	87.1° 22:00	6.96	0%	111.0°
2028-08-21 Mon	100	—	unknown	21:55–03:55 (good, 6.0 h)	87.1° 21:55	7.02	4%	105.4°
2028-08-22 Tue	100	—	unknown	21:55–03:50 (good, 5.92 h)	87.1° 21:55	7.07	9%	99.0°
2028-08-23 Wed	100	—	unknown	21:50–03:50 (good, 6.0 h)	87.1° 21:50	7.13	17%	92.1°
2028-08-24 Thu	100	—	unknown	21:50–03:45 (good, 5.92 h)	87.1° 21:45	7.19	27%	85.4°
2028-08-25 Fri	100	—	unknown	21:50–03:40 (good, 5.83 h)	87.1° 21:40	7.25	38%	79.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-27&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.