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: 08-24 (100), 08-25 (100), 08-26 (100), 08-27 (100), 08-28 (100) — by astronomy; check the weather when the night is within four days.

2043-08-18astronomy score per night — click a bar for that night2043-09-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-08-18 Tue	66	—	unknown	22:05–02:05 (good, 4.0 h)	87.1° 22:10	6.81	97%	67.7°
2043-08-19 Wed	67	—	unknown	22:00–01:15 (good, 3.25 h)	87.1° 22:05	6.87	99%	69.9°
2043-08-20 Thu	69	—	unknown	22:00–01:05 (good, 3.08 h)	87.1° 22:05	6.92	100%	73.2°
2043-08-21 Fri	73	—	unknown	21:55–01:25 (good, 3.5 h)	87.1° 22:00	6.98	98%	77.4°
2043-08-22 Sat	78	—	unknown	21:55–01:55 (good, 4.0 h)	87.1° 21:55	7.04	94%	82.4°
2043-08-23 Sun	82	—	unknown	21:55–02:35 (good, 4.67 h)	87.1° 21:50	7.1	87%	87.8°
2043-08-24 Mon	100	—	unknown	21:50–03:15 (good, 5.42 h)	87.1° 21:50	7.15	78%	93.4°
2043-08-25 Tue	100	—	unknown	21:50–03:20 (good, 5.5 h)	87.1° 21:45	7.21	68%	98.8°
2043-08-26 Wed	100	—	unknown	21:50–03:25 (good, 5.58 h)	87.1° 21:40	7.27	57%	103.8°
2043-08-27 Thu	100	—	unknown	21:45–03:25 (good, 5.67 h)	87.1° 21:35	7.32	46%	107.9°
2043-08-28 Fri	100	—	unknown	21:45–03:25 (good, 5.67 h)	87.1° 21:30	7.38	34%	111.0°
2043-08-29 Sat	100	—	unknown	21:40–03:25 (good, 5.75 h)	87.1° 21:30	7.44	24%	112.8°
2043-08-30 Sun	100	—	unknown	21:40–03:20 (good, 5.67 h)	87.1° 21:25	7.49	15%	113.2°
2043-08-31 Mon	100	—	unknown	21:40–03:20 (good, 5.67 h)	87.1° 21:20	7.55	8%	112.2°
2043-09-01 Tue	100	—	unknown	21:35–03:15 (good, 5.67 h)	87.1° 21:15	7.6	3%	109.8°
2043-09-02 Wed	100	—	unknown	21:35–03:10 (good, 5.58 h)	87.1° 21:10	7.66	0%	106.5°
2043-09-03 Thu	100	—	unknown	21:30–03:10 (good, 5.67 h)	87.1° 21:10	7.72	0%	102.3°
2043-09-04 Fri	100	—	unknown	21:30–03:05 (good, 5.58 h)	87.1° 21:05	7.77	2%	97.7°
2043-09-05 Sat	100	—	unknown	21:30–03:00 (good, 5.5 h)	87.1° 21:00	7.83	6%	92.9°
2043-09-06 Sun	100	—	unknown	21:25–02:55 (good, 5.5 h)	87.1° 20:55	7.88	11%	88.0°
2043-09-07 Mon	100	—	unknown	21:25–02:50 (good, 5.42 h)	87.1° 20:55	7.94	18%	83.3°
2043-09-08 Tue	100	—	unknown	21:20–02:50 (good, 5.5 h)	87.1° 20:50	7.99	26%	78.9°
2043-09-09 Wed	100	—	unknown	21:20–02:45 (good, 5.42 h)	87.1° 20:45	8.05	35%	75.0°
2043-09-10 Thu	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:40	8.1	44%	71.7°
2043-09-11 Fri	99	—	unknown	21:15–02:35 (good, 5.33 h)	87.1° 20:35	8.15	54%	69.1°
2043-09-12 Sat	92	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:35	8.21	63%	67.4°
2043-09-13 Sun	85	—	unknown	21:10–02:30 (good, 5.33 h)	87.1° 20:30	8.26	72%	66.8°
2043-09-14 Mon	70	—	unknown	21:10–01:55 (good, 4.75 h)	87.1° 20:25	8.31	81%	67.3°
2043-09-15 Tue	62	—	unknown	21:10–00:45 (good, 3.58 h)	87.1° 20:20	8.37	88%	69.0°
2043-09-16 Wed	59	—	unknown	21:05–23:45 (good, 2.67 h)	87.1° 20:15	8.42	94%	71.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-08-18&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.