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: 08-20 (100), 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100) — by astronomy; check the weather when the night is within four days.

2040-08-20astronomy score per night — click a bar for that night2040-09-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-08-20 Mon	100	—	unknown	00:15–04:55 (good, 4.67 h)	79.2° 04:55	6.96	97%	87.1°
2040-08-21 Tue	67	—	unknown	01:50–04:55 (good, 3.08 h)	79.2° 04:55	7.02	100%	73.1°
2040-08-22 Wed	48	—	unknown	23:10–05:00 (marginal, 5.83 h)	79.2° 04:50	7.08	99%	59.4°
2040-08-23 Thu	35	—	unknown	23:10–05:00 (marginal, 5.83 h)	79.2° 04:45	7.14	96%	46.4°
2040-08-24 Fri	28	—	unknown	23:05–05:00 (marginal, 5.92 h)	79.2° 04:40	7.19	91%	34.6°
2040-08-25 Sat	32	—	unknown	22:55–05:05 (marginal, 6.17 h)	79.2° 04:35	7.25	84%	25.4°
2040-08-26 Sun	42	—	unknown	22:40–05:05 (marginal, 6.42 h)	79.2° 04:35	7.31	75%	21.5°
2040-08-27 Mon	56	—	unknown	22:35–05:05 (marginal, 6.5 h)	79.2° 04:30	7.36	65%	24.7°
2040-08-28 Tue	80	—	unknown	23:00–05:00 (good, 6.0 h)	79.2° 04:25	7.42	55%	32.6°
2040-08-29 Wed	85	—	unknown	22:55–05:10 (good, 6.25 h)	79.2° 04:20	7.48	46%	42.4°
2040-08-30 Thu	90	—	unknown	22:50–05:10 (good, 6.33 h)	79.2° 04:20	7.53	36%	52.8°
2040-08-31 Fri	96	—	unknown	22:45–05:10 (good, 6.42 h)	79.2° 04:15	7.59	27%	63.5°
2040-09-01 Sat	100	—	unknown	22:45–05:15 (good, 6.5 h)	79.2° 04:10	7.65	19%	74.4°
2040-09-02 Sun	100	—	unknown	22:40–05:15 (good, 6.58 h)	79.2° 04:05	7.7	12%	85.4°
2040-09-03 Mon	100	—	unknown	22:35–05:15 (good, 6.67 h)	79.2° 04:00	7.76	7%	96.5°
2040-09-04 Tue	100	—	unknown	22:30–05:15 (good, 6.75 h)	79.2° 04:00	7.81	3%	107.6°
2040-09-05 Wed	100	—	unknown	22:25–05:20 (good, 6.92 h)	79.2° 03:55	7.87	1%	118.7°
2040-09-06 Thu	100	—	unknown	22:25–05:20 (good, 6.92 h)	79.2° 03:50	7.92	0%	129.7°
2040-09-07 Fri	100	—	unknown	22:20–05:20 (good, 7.0 h)	79.2° 03:45	7.98	2%	140.3°
2040-09-08 Sat	100	—	unknown	22:15–05:20 (good, 7.08 h)	79.2° 03:40	8.03	5%	150.0°
2040-09-09 Sun	100	—	unknown	22:10–05:25 (good, 7.25 h)	79.2° 03:40	8.08	11%	157.0°
2040-09-10 Mon	100	—	unknown	22:05–05:25 (good, 7.33 h)	79.2° 03:35	8.14	18%	158.3°
2040-09-11 Tue	100	—	unknown	22:05–05:25 (good, 7.33 h)	79.2° 03:30	8.19	27%	152.7°
2040-09-12 Wed	100	—	unknown	22:00–05:25 (good, 7.42 h)	79.2° 03:25	8.25	37%	143.0°
2040-09-13 Thu	100	—	unknown	22:00–05:30 (good, 7.5 h)	79.2° 03:25	8.3	48%	131.4°
2040-09-14 Fri	100	—	unknown	21:55–05:30 (good, 7.58 h)	79.2° 03:20	8.35	60%	118.9°
2040-09-15 Sat	100	—	unknown	22:00–05:30 (good, 7.5 h)	79.2° 03:15	8.4	70%	105.7°
2040-09-16 Sun	100	—	unknown	22:05–05:30 (good, 7.42 h)	79.2° 03:10	8.46	80%	92.3°
2040-09-17 Mon	100	—	unknown	22:45–05:35 (good, 6.83 h)	79.2° 03:05	8.51	89%	78.7°
2040-09-18 Tue	100	—	unknown	00:40–05:35 (good, 4.92 h)	79.2° 03:05	8.56	95%	65.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-08-20&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.