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: 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100), 08-22 (100) — by astronomy; check the weather when the night is within four days.

2038-08-15astronomy score per night — click a bar for that night2038-09-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-08-15 Sun	72	—	unknown	22:10–01:50 (good, 3.67 h)	87.1° 22:20	6.65	99%	76.0°
2038-08-16 Mon	77	—	unknown	22:05–02:20 (good, 4.25 h)	87.1° 22:20	6.7	96%	81.5°
2038-08-17 Tue	82	—	unknown	22:05–02:55 (good, 4.83 h)	87.1° 22:15	6.76	91%	87.2°
2038-08-18 Wed	100	—	unknown	22:05–03:30 (good, 5.42 h)	87.1° 22:10	6.82	85%	92.9°
2038-08-19 Thu	100	—	unknown	22:00–03:40 (good, 5.67 h)	87.1° 22:05	6.88	77%	98.4°
2038-08-20 Fri	100	—	unknown	22:00–03:45 (good, 5.75 h)	87.1° 22:00	6.94	69%	103.6°
2038-08-21 Sat	100	—	unknown	21:55–03:45 (good, 5.83 h)	87.1° 22:00	6.99	60%	108.3°
2038-08-22 Sun	100	—	unknown	21:55–03:45 (good, 5.83 h)	87.1° 21:55	7.05	50%	112.3°
2038-08-23 Mon	100	—	unknown	21:55–03:45 (good, 5.83 h)	87.1° 21:50	7.11	41%	115.5°
2038-08-24 Tue	100	—	unknown	21:50–03:40 (good, 5.83 h)	87.1° 21:45	7.16	31%	117.5°
2038-08-25 Wed	100	—	unknown	21:50–03:40 (good, 5.83 h)	87.1° 21:45	7.22	22%	118.1°
2038-08-26 Thu	100	—	unknown	21:45–03:35 (good, 5.83 h)	87.1° 21:40	7.28	14%	117.3°
2038-08-27 Fri	100	—	unknown	21:45–03:35 (good, 5.83 h)	87.1° 21:35	7.33	8%	114.9°
2038-08-28 Sat	100	—	unknown	21:45–03:30 (good, 5.75 h)	87.1° 21:30	7.39	3%	111.1°
2038-08-29 Sun	100	—	unknown	21:40–03:25 (good, 5.75 h)	87.1° 21:25	7.45	0%	105.9°
2038-08-30 Mon	100	—	unknown	21:40–03:20 (good, 5.67 h)	87.1° 21:25	7.5	0%	99.9°
2038-08-31 Tue	100	—	unknown	21:35–03:20 (good, 5.75 h)	87.1° 21:20	7.56	3%	93.2°
2038-09-01 Wed	100	—	unknown	21:35–03:15 (good, 5.67 h)	87.1° 21:15	7.62	9%	86.3°
2038-09-02 Thu	100	—	unknown	21:35–03:10 (good, 5.58 h)	87.1° 21:10	7.67	17%	79.6°
2038-09-03 Fri	100	—	unknown	21:30–03:05 (good, 5.58 h)	87.1° 21:05	7.73	26%	73.5°
2038-09-04 Sat	100	—	unknown	21:30–03:05 (good, 5.58 h)	87.1° 21:05	7.78	37%	68.4°
2038-09-05 Sun	100	—	unknown	21:25–03:00 (good, 5.58 h)	87.1° 21:00	7.84	48%	64.6°
2038-09-06 Mon	94	—	unknown	21:25–02:55 (good, 5.5 h)	87.1° 20:55	7.89	60%	62.5°
2038-09-07 Tue	87	—	unknown	21:25–02:50 (good, 5.42 h)	87.1° 20:50	7.95	70%	62.0°
2038-09-08 Wed	79	—	unknown	21:20–02:45 (good, 5.42 h)	87.1° 20:50	8.0	79%	63.2°
2038-09-09 Thu	64	—	unknown	21:20–01:20 (good, 4.0 h)	87.1° 20:45	8.06	87%	65.9°
2038-09-10 Fri	61	—	unknown	21:15–00:20 (good, 3.08 h)	87.1° 20:40	8.11	93%	69.7°
2038-09-11 Sat	62	—	unknown	21:15–00:05 (good, 2.83 h)	87.1° 20:35	8.16	97%	74.4°
2038-09-12 Sun	66	—	unknown	21:15–00:15 (good, 3.0 h)	87.1° 20:30	8.22	100%	79.7°
2038-09-13 Mon	72	—	unknown	21:10–00:35 (good, 3.42 h)	87.1° 20:30	8.27	100%	85.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-08-15&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.