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 Triangulum Pinwheel: 06-05 (2), 06-06 (2), 06-07 (2), 06-08 (2), 06-09 (2) — by astronomy; check the weather when the night is within four days.

2047-05-15astronomy score per night — click a bar for that night2047-06-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-05-15 Wed	0	—	unknown	—	79.2° 11:20	5.58	58%	77.1°
2047-05-16 Thu	0	—	unknown	—	79.2° 11:20	5.53	48%	65.0°
2047-05-17 Fri	0	—	unknown	—	79.2° 11:15	5.48	38%	53.2°
2047-05-18 Sat	0	—	unknown	—	79.2° 11:10	5.42	29%	41.8°
2047-05-19 Sun	0	—	unknown	—	79.2° 11:05	5.37	21%	31.0°
2047-05-20 Mon	0	—	unknown	—	79.2° 11:00	5.32	14%	21.4°
2047-05-21 Tue	0	—	unknown	—	79.2° 11:00	5.27	8%	15.0°
2047-05-22 Wed	0	—	unknown	—	79.2° 10:55	5.23	4%	16.3°
2047-05-23 Thu	0	—	unknown	—	79.2° 10:50	5.18	1%	24.2°
2047-05-24 Fri	0	—	unknown	—	79.2° 10:45	5.13	0%	34.4°
2047-05-25 Sat	0	—	unknown	—	79.2° 10:40	5.09	1%	45.6°
2047-05-26 Sun	0	—	unknown	—	79.2° 10:40	5.04	4%	57.2°
2047-05-27 Mon	0	—	unknown	—	79.2° 10:35	5.0	9%	69.2°
2047-05-28 Tue	0	—	unknown	—	79.2° 10:30	4.96	16%	81.4°
2047-05-29 Wed	0	—	unknown	—	79.2° 10:25	4.91	24%	93.9°
2047-05-30 Thu	1	—	unknown	—	79.2° 10:25	4.87	33%	106.6°
2047-05-31 Fri	1	—	unknown	—	79.2° 10:20	4.84	44%	119.5°
2047-06-01 Sat	1	—	unknown	—	79.2° 10:15	4.8	55%	132.5°
2047-06-02 Sun	1	—	unknown	—	79.2° 10:10	4.76	66%	145.5°
2047-06-03 Mon	1	—	unknown	—	79.2° 10:05	4.73	77%	157.7°
2047-06-04 Tue	1	—	unknown	—	79.2° 10:05	4.7	86%	165.4°
2047-06-05 Wed	2	—	unknown	04:30–04:35 (marginal, 0.08 h)	79.2° 10:00	4.67	93%	161.2°
2047-06-06 Thu	2	—	unknown	—	79.2° 09:55	4.64	98%	149.5°
2047-06-07 Fri	2	—	unknown	—	79.2° 09:50	4.61	100%	136.0°
2047-06-08 Sat	2	—	unknown	—	79.2° 09:45	4.58	99%	122.1°
2047-06-09 Sun	2	—	unknown	—	79.2° 09:45	4.56	95%	108.3°
2047-06-10 Mon	2	—	unknown	—	79.2° 09:40	4.54	90%	94.8°
2047-06-11 Tue	2	—	unknown	—	79.2° 09:35	4.52	82%	81.7°
2047-06-12 Wed	2	—	unknown	—	79.2° 09:30	4.5	73%	69.0°
2047-06-13 Thu	2	—	unknown	03:35–03:40 (marginal, 0.08 h)	79.2° 09:30	4.48	64%	56.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-05-15&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.