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: 08-14 (100), 08-15 (100), 08-16 (100), 08-17 (100), 08-18 (100) — by astronomy; check the weather when the night is within four days.

2031-07-24astronomy score per night — click a bar for that night2031-08-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-07-24 Thu	79	—	unknown	01:20–04:15 (good, 2.92 h)	79.1° 06:45	5.41	25%	145.8°
2031-07-25 Fri	82	—	unknown	01:15–04:15 (good, 3.0 h)	79.1° 06:40	5.46	34%	155.7°
2031-07-26 Sat	84	—	unknown	01:10–04:15 (good, 3.08 h)	79.1° 06:40	5.51	45%	162.1°
2031-07-27 Sun	85	—	unknown	01:05–04:15 (good, 3.17 h)	79.1° 06:35	5.57	55%	160.4°
2031-07-28 Mon	89	—	unknown	01:10–04:20 (good, 3.17 h)	79.1° 06:30	5.62	66%	151.5°
2031-07-29 Tue	90	—	unknown	01:05–04:20 (good, 3.25 h)	79.1° 06:25	5.67	77%	139.6°
2031-07-30 Wed	89	—	unknown	01:05–04:20 (good, 3.25 h)	79.1° 06:20	5.73	86%	126.3°
2031-07-31 Thu	86	—	unknown	01:05–04:25 (good, 3.33 h)	79.1° 06:20	5.78	93%	112.3°
2031-08-01 Fri	64	—	unknown	01:10–04:25 (good, 3.25 h)	79.1° 06:15	5.84	98%	98.0°
2031-08-02 Sat	50	—	unknown	02:20–04:25 (good, 2.08 h)	79.1° 06:10	5.89	100%	83.5°
2031-08-03 Sun	37	—	unknown	04:05–04:30 (good, 0.42 h)	79.1° 06:05	5.95	99%	69.1°
2031-08-04 Mon	28	—	unknown	00:25–04:30 (marginal, 4.08 h)	79.1° 06:05	6.0	95%	55.2°
2031-08-05 Tue	22	—	unknown	00:25–04:30 (marginal, 4.08 h)	79.1° 06:00	6.06	88%	42.0°
2031-08-06 Wed	22	—	unknown	00:20–04:35 (marginal, 4.25 h)	79.1° 05:55	6.12	80%	30.0°
2031-08-07 Thu	30	—	unknown	00:05–04:35 (marginal, 4.5 h)	79.1° 05:50	6.17	71%	20.7°
2031-08-08 Fri	41	—	unknown	23:50–04:35 (marginal, 4.75 h)	79.1° 05:45	6.23	61%	17.6°
2031-08-09 Sat	56	—	unknown	00:40–04:40 (good, 4.0 h)	79.1° 05:45	6.29	51%	22.6°
2031-08-10 Sun	76	—	unknown	00:10–04:40 (good, 4.5 h)	79.1° 05:40	6.34	41%	31.7°
2031-08-11 Mon	86	—	unknown	00:10–04:40 (good, 4.5 h)	79.1° 05:35	6.4	32%	42.1°
2031-08-12 Tue	92	—	unknown	00:05–04:45 (good, 4.67 h)	79.1° 05:30	6.46	23%	53.0°
2031-08-13 Wed	99	—	unknown	00:00–04:45 (good, 4.75 h)	79.1° 05:25	6.52	16%	64.1°
2031-08-14 Thu	100	—	unknown	23:55–04:45 (good, 4.83 h)	79.1° 05:25	6.57	10%	75.3°
2031-08-15 Fri	100	—	unknown	23:50–04:45 (good, 4.92 h)	79.1° 05:20	6.63	5%	86.6°
2031-08-16 Sat	100	—	unknown	23:50–04:50 (good, 5.0 h)	79.1° 05:15	6.69	2%	97.9°
2031-08-17 Sun	100	—	unknown	23:45–04:50 (good, 5.08 h)	79.1° 05:10	6.75	0%	109.3°
2031-08-18 Mon	100	—	unknown	23:40–04:50 (good, 5.17 h)	79.1° 05:10	6.8	1%	120.7°
2031-08-19 Tue	100	—	unknown	23:35–04:55 (good, 5.33 h)	79.1° 05:05	6.86	3%	132.1°
2031-08-20 Wed	100	—	unknown	23:35–04:55 (good, 5.33 h)	79.1° 05:00	6.92	7%	143.2°
2031-08-21 Thu	100	—	unknown	23:30–04:55 (good, 5.42 h)	79.1° 04:55	6.98	14%	153.5°
2031-08-22 Fri	100	—	unknown	23:25–05:00 (good, 5.58 h)	79.1° 04:50	7.03	21%	161.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-07-24&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.