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 Seven Sisters: 07-15 (3), 07-16 (3), 07-11 (2), 07-12 (2), 07-13 (2) — by astronomy; check the weather when the night is within four days.

2038-06-17astronomy score per night — click a bar for that night2038-07-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-06-17 Thu	0	—	unknown	—	72.5° 11:25	4.43	99%	141.7°
2038-06-18 Fri	0	—	unknown	—	72.5° 11:20	4.43	96%	128.0°
2038-06-19 Sat	0	—	unknown	—	72.5° 11:15	4.42	90%	114.6°
2038-06-20 Sun	0	—	unknown	—	72.5° 11:10	4.42	83%	101.5°
2038-06-21 Mon	0	—	unknown	—	72.5° 11:05	4.42	74%	88.8°
2038-06-22 Tue	0	—	unknown	—	72.5° 11:05	4.43	65%	76.5°
2038-06-23 Wed	0	—	unknown	—	72.5° 11:00	4.43	56%	64.4°
2038-06-24 Thu	0	—	unknown	—	72.5° 10:55	4.44	46%	52.6°
2038-06-25 Fri	0	—	unknown	—	72.5° 10:50	4.45	37%	40.9°
2038-06-26 Sat	0	—	unknown	—	72.5° 10:50	4.46	28%	29.4°
2038-06-27 Sun	0	—	unknown	—	72.5° 10:45	4.47	20%	18.2°
2038-06-28 Mon	0	—	unknown	—	72.5° 10:40	4.48	13%	8.8°
2038-06-29 Tue	0	—	unknown	—	72.5° 10:35	4.5	7%	10.7°
2038-06-30 Wed	0	—	unknown	—	72.5° 10:30	4.52	3%	21.2°
2038-07-01 Thu	0	—	unknown	—	72.5° 10:30	4.54	0%	33.3°
2038-07-02 Fri	0	—	unknown	—	72.5° 10:25	4.56	0%	45.9°
2038-07-03 Sat	0	—	unknown	—	72.5° 10:20	4.59	2%	58.8°
2038-07-04 Sun	0	—	unknown	—	72.5° 10:15	4.61	6%	72.0°
2038-07-05 Mon	0	—	unknown	—	72.5° 10:10	4.64	13%	85.4°
2038-07-06 Tue	0	—	unknown	—	72.5° 10:10	4.67	21%	99.0°
2038-07-07 Wed	1	—	unknown	—	72.5° 10:05	4.7	31%	112.8°
2038-07-08 Thu	1	—	unknown	—	72.5° 10:00	4.73	42%	126.7°
2038-07-09 Fri	1	—	unknown	—	72.5° 09:55	4.77	53%	140.6°
2038-07-10 Sat	1	—	unknown	—	72.5° 09:55	4.8	64%	154.3°
2038-07-11 Sun	2	—	unknown	—	72.5° 09:50	4.84	75%	167.3°
2038-07-12 Mon	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:45	4.88	84%	171.5°
2038-07-13 Tue	2	—	unknown	04:35–04:45 (marginal, 0.17 h)	72.5° 09:40	4.92	92%	160.3°
2038-07-14 Wed	2	—	unknown	04:35–04:45 (marginal, 0.17 h)	72.5° 09:35	4.96	97%	146.9°
2038-07-15 Thu	3	—	unknown	04:35–04:50 (marginal, 0.25 h)	72.5° 09:35	5.0	100%	133.2°
2038-07-16 Fri	3	—	unknown	04:35–04:50 (marginal, 0.25 h)	72.5° 09:30	5.05	100%	119.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-06-17&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.