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.

2038-07-04astronomy score per night — click a bar for that night2038-08-02

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-07-04 Sun	—	unknown	—	42.9° 12:10	4.61	6%	56.4°
2038-07-05 Mon	—	unknown	—	42.9° 12:00	4.64	13%	68.1°
2038-07-06 Tue	—	unknown	—	42.9° 12:00	4.67	21%	80.2°
2038-07-07 Wed	—	unknown	—	42.9° 11:55	4.7	31%	92.5°
2038-07-08 Thu	—	unknown	—	42.9° 11:50	4.73	42%	105.0°
2038-07-09 Fri	—	unknown	—	42.9° 11:45	4.77	53%	117.3°
2038-07-10 Sat	—	unknown	—	42.9° 11:40	4.8	64%	129.2°
2038-07-11 Sun	—	unknown	—	42.9° 11:35	4.84	75%	140.2°
2038-07-12 Mon	—	unknown	—	42.9° 11:35	4.88	84%	148.9°
2038-07-13 Tue	—	unknown	—	42.9° 11:30	4.92	92%	153.0°
2038-07-14 Wed	—	unknown	—	42.9° 11:25	4.96	97%	150.6°
2038-07-15 Thu	—	unknown	—	42.9° 11:20	5.0	100%	143.1°
2038-07-16 Fri	—	unknown	—	42.9° 11:15	5.05	100%	133.2°
2038-07-17 Sat	—	unknown	—	42.9° 11:15	5.09	98%	122.3°
2038-07-18 Sun	—	unknown	—	42.9° 11:10	5.14	93%	111.0°
2038-07-19 Mon	—	unknown	—	42.9° 11:05	5.18	87%	99.8°
2038-07-20 Tue	—	unknown	—	42.9° 11:00	5.23	80%	88.7°
2038-07-21 Wed	—	unknown	—	42.9° 10:55	5.28	71%	77.9°
2038-07-22 Thu	—	unknown	—	42.9° 10:55	5.33	62%	67.4°
2038-07-23 Fri	—	unknown	—	42.9° 10:50	5.38	53%	57.2°
2038-07-24 Sat	—	unknown	—	42.9° 10:45	5.43	43%	47.5°
2038-07-25 Sun	—	unknown	—	42.9° 10:40	5.48	34%	38.7°
2038-07-26 Mon	—	unknown	—	42.9° 10:40	5.53	25%	31.4°
2038-07-27 Tue	—	unknown	—	42.9° 10:35	5.58	17%	27.3°
2038-07-28 Wed	—	unknown	—	42.9° 10:30	5.64	10%	28.1°
2038-07-29 Thu	—	unknown	—	42.9° 10:25	5.69	5%	33.6°
2038-07-30 Fri	—	unknown	—	42.9° 10:20	5.74	1%	42.3°
2038-07-31 Sat	—	unknown	—	42.9° 10:20	5.8	0%	52.9°
2038-08-01 Sun	—	unknown	—	42.9° 10:15	5.85	1%	64.5°
2038-08-02 Mon	—	unknown	—	42.9° 10:10	5.91	5%	76.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-07-04&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.