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: 04-25 (100), 04-26 (100), 04-27 (100), 04-28 (100), 04-29 (100) — by astronomy; check the weather when the night is within four days.

2039-04-25astronomy score per night — click a bar for that night2039-05-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-04-25 Mon	100	—	unknown	23:50–04:45 (good, 4.92 h)	87.1° 05:45	6.72	6%	112.2°
2039-04-26 Tue	100	—	unknown	23:45–04:40 (good, 4.92 h)	87.1° 05:40	6.66	11%	114.8°
2039-04-27 Wed	100	—	unknown	23:45–04:40 (good, 4.92 h)	87.1° 05:35	6.6	17%	116.3°
2039-04-28 Thu	100	—	unknown	23:40–04:35 (good, 4.92 h)	87.1° 05:30	6.55	25%	116.6°
2039-04-29 Fri	100	—	unknown	23:40–04:35 (good, 4.92 h)	87.1° 05:30	6.49	34%	115.7°
2039-04-30 Sat	100	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:25	6.43	43%	113.6°
2039-05-01 Sun	100	—	unknown	23:35–04:30 (good, 4.92 h)	87.1° 05:20	6.37	53%	110.2°
2039-05-02 Mon	100	—	unknown	23:35–04:30 (good, 4.92 h)	87.1° 05:15	6.31	64%	105.8°
2039-05-03 Tue	100	—	unknown	23:40–04:30 (good, 4.83 h)	87.1° 05:10	6.26	74%	100.6°
2039-05-04 Wed	85	—	unknown	23:45–04:25 (good, 4.67 h)	87.1° 05:10	6.2	83%	94.6°
2039-05-05 Thu	80	—	unknown	00:30–04:25 (good, 3.92 h)	87.1° 05:05	6.14	91%	88.3°
2039-05-06 Fri	70	—	unknown	01:10–04:20 (good, 3.17 h)	87.1° 05:00	6.08	96%	81.8°
2039-05-07 Sat	62	—	unknown	01:45–04:20 (good, 2.58 h)	87.1° 04:55	6.03	100%	75.6°
2039-05-08 Sun	58	—	unknown	02:00–04:20 (good, 2.33 h)	87.1° 04:50	5.97	100%	70.3°
2039-05-09 Mon	58	—	unknown	01:35–04:15 (good, 2.67 h)	87.1° 04:50	5.91	97%	66.2°
2039-05-10 Tue	78	—	unknown	23:35–04:15 (good, 4.67 h)	87.1° 04:45	5.86	91%	63.9°
2039-05-11 Wed	88	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.8	83%	63.4°
2039-05-12 Thu	95	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.75	74%	64.8°
2039-05-13 Fri	100	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.69	63%	67.7°
2039-05-14 Sat	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.64	52%	71.8°
2039-05-15 Sun	100	—	unknown	22:30–04:05 (good, 5.58 h)	87.1° 04:25	5.59	42%	76.6°
2039-05-16 Mon	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.53	32%	81.9°
2039-05-17 Tue	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.48	23%	87.4°
2039-05-18 Wed	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.43	15%	92.9°
2039-05-19 Thu	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.38	9%	98.2°
2039-05-20 Fri	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.33	4%	103.2°
2039-05-21 Sat	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.28	1%	107.6°
2039-05-22 Sun	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.23	0%	111.3°
2039-05-23 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.18	1%	114.2°
2039-05-24 Tue	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.13	3%	116.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-04-25&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.