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: 07-28 (100), 07-29 (100), 07-30 (100), 07-31 (100), 08-01 (100) — by astronomy; check the weather when the night is within four days.

2040-07-28astronomy score per night — click a bar for that night2040-08-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-07-28 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:30	5.66	70%	92.2°
2040-07-29 Sun	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.1° 23:25	5.72	60%	97.7°
2040-07-30 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:25	5.77	49%	102.7°
2040-07-31 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:20	5.83	39%	107.0°
2040-08-01 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.1° 23:15	5.88	30%	110.6°
2040-08-02 Thu	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:10	5.94	22%	113.1°
2040-08-03 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:05	5.99	14%	114.6°
2040-08-04 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.1° 23:05	6.05	8%	115.0°
2040-08-05 Sun	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 23:00	6.1	4%	114.2°
2040-08-06 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 22:55	6.16	1%	112.4°
2040-08-07 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.1° 22:50	6.22	0%	109.6°
2040-08-08 Wed	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.1° 22:50	6.28	1%	106.0°
2040-08-09 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.1° 22:45	6.33	4%	101.7°
2040-08-10 Fri	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.1° 22:40	6.39	8%	96.9°
2040-08-11 Sat	100	—	unknown	22:15–04:35 (good, 6.33 h)	87.1° 22:35	6.45	14%	91.7°
2040-08-12 Sun	100	—	unknown	22:15–04:30 (good, 6.25 h)	87.1° 22:30	6.5	22%	86.4°
2040-08-13 Mon	100	—	unknown	22:10–04:25 (good, 6.25 h)	87.1° 22:30	6.56	31%	81.2°
2040-08-14 Tue	100	—	unknown	22:10–04:25 (good, 6.25 h)	87.1° 22:25	6.62	41%	76.2°
2040-08-15 Wed	100	—	unknown	22:10–04:20 (good, 6.17 h)	87.1° 22:20	6.68	52%	71.8°
2040-08-16 Thu	100	—	unknown	22:05–04:15 (good, 6.17 h)	87.1° 22:15	6.73	63%	68.2°
2040-08-17 Fri	96	—	unknown	22:05–04:10 (good, 6.08 h)	87.1° 22:10	6.79	73%	65.9°
2040-08-18 Sat	89	—	unknown	22:00–04:10 (good, 6.17 h)	87.1° 22:10	6.85	83%	65.1°
2040-08-19 Sun	80	—	unknown	22:00–04:05 (good, 6.08 h)	87.1° 22:05	6.91	91%	66.0°
2040-08-20 Mon	67	—	unknown	22:00–01:50 (good, 3.83 h)	87.1° 22:00	6.96	97%	68.7°
2040-08-21 Tue	69	—	unknown	21:55–01:20 (good, 3.42 h)	87.1° 21:55	7.02	100%	72.8°
2040-08-22 Wed	73	—	unknown	21:55–01:30 (good, 3.58 h)	87.1° 21:55	7.08	99%	77.9°
2040-08-23 Thu	78	—	unknown	21:50–01:55 (good, 4.08 h)	87.1° 21:50	7.14	96%	83.7°
2040-08-24 Fri	83	—	unknown	21:50–02:35 (good, 4.75 h)	87.1° 21:45	7.19	91%	89.7°
2040-08-25 Sat	100	—	unknown	21:50–03:10 (good, 5.33 h)	87.1° 21:40	7.25	84%	95.5°
2040-08-26 Sun	100	—	unknown	21:45–03:15 (good, 5.5 h)	87.1° 21:35	7.31	75%	100.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-07-28&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.