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: 05-28 (100), 05-29 (100), 05-30 (100), 05-31 (100), 06-01 (100) — by astronomy; check the weather when the night is within four days.

2043-05-19astronomy score per night — click a bar for that night2043-06-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-05-19 Tue	84	—	unknown	22:55–04:00 (good, 5.08 h)	87.1° 04:10	5.38	86%	90.8°
2043-05-20 Wed	80	—	unknown	23:25–04:00 (good, 4.58 h)	87.1° 04:05	5.33	92%	86.2°
2043-05-21 Thu	77	—	unknown	23:45–04:00 (good, 4.25 h)	87.1° 04:00	5.28	96%	81.6°
2043-05-22 Fri	73	—	unknown	23:55–03:55 (good, 4.0 h)	87.1° 03:55	5.23	99%	77.5°
2043-05-23 Sat	68	—	unknown	23:50–03:55 (good, 4.08 h)	87.1° 03:55	5.18	100%	73.7°
2043-05-24 Sun	66	—	unknown	23:20–03:55 (good, 4.58 h)	87.1° 03:50	5.13	99%	70.6°
2043-05-25 Mon	68	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.09	96%	68.4°
2043-05-26 Tue	89	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.04	92%	67.0°
2043-05-27 Wed	95	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.0	86%	66.8°
2043-05-28 Thu	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.96	78%	67.7°
2043-05-29 Fri	100	—	unknown	22:55–03:50 (good, 4.92 h)	87.1° 03:30	4.92	69%	69.7°
2043-05-30 Sat	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:25	4.88	59%	72.8°
2043-05-31 Sun	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.84	49%	76.8°
2043-06-01 Mon	100	—	unknown	22:55–03:45 (good, 4.83 h)	87.1° 03:20	4.8	38%	81.6°
2043-06-02 Tue	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:15	4.76	27%	87.0°
2043-06-03 Wed	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:10	4.73	17%	92.7°
2043-06-04 Thu	100	—	unknown	23:00–03:45 (good, 4.75 h)	87.1° 03:05	4.7	9%	98.4°
2043-06-05 Fri	100	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:00	4.67	4%	103.7°
2043-06-06 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 03:00	4.64	1%	108.1°
2043-06-07 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.61	0%	111.3°
2043-06-08 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.58	4%	113.1°
2043-06-09 Tue	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.56	9%	113.2°
2043-06-10 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.54	16%	111.8°
2043-06-11 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:40	4.52	25%	109.2°
2043-06-12 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.5	35%	105.7°
2043-06-13 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.48	45%	101.5°
2043-06-14 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.47	55%	97.0°
2043-06-15 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.45	64%	92.3°
2043-06-16 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.44	73%	87.5°
2043-06-17 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:15	4.43	81%	82.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-05-19&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.