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: 09-28 (100), 09-29 (100), 09-30 (100), 10-01 (100), 10-02 (100) — by astronomy; check the weather when the night is within four days.

2040-09-22astronomy score per night — click a bar for that night2040-10-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-09-22 Sat	34	—	unknown	21:10–05:40 (marginal, 8.5 h)	79.2° 02:45	8.77	94%	22.1°
2040-09-23 Sun	44	—	unknown	20:50–05:40 (marginal, 8.83 h)	79.2° 02:45	8.82	88%	22.5°
2040-09-24 Mon	71	—	unknown	21:10–21:30 (good, 0.33 h)	79.2° 02:40	8.87	80%	29.2°
2040-09-25 Tue	83	—	unknown	21:10–01:00 (good, 3.83 h)	79.2° 02:35	8.92	71%	38.7°
2040-09-26 Wed	88	—	unknown	21:05–05:00 (good, 7.92 h)	79.2° 02:30	8.97	62%	49.2°
2040-09-27 Thu	93	—	unknown	21:00–05:45 (good, 8.75 h)	79.2° 02:30	9.01	53%	60.0°
2040-09-28 Fri	100	—	unknown	20:55–05:45 (good, 8.83 h)	79.2° 02:25	9.06	43%	70.9°
2040-09-29 Sat	100	—	unknown	20:50–05:45 (good, 8.92 h)	79.2° 02:20	9.11	34%	81.9°
2040-09-30 Sun	100	—	unknown	20:50–05:50 (good, 9.0 h)	79.2° 02:15	9.16	25%	92.9°
2040-10-01 Mon	100	—	unknown	20:45–05:50 (good, 9.08 h)	79.2° 02:10	9.21	18%	104.0°
2040-10-02 Tue	100	—	unknown	20:40–05:50 (good, 9.17 h)	79.2° 02:10	9.26	11%	115.1°
2040-10-03 Wed	100	—	unknown	20:35–05:50 (good, 9.25 h)	79.2° 02:05	9.3	6%	126.2°
2040-10-04 Thu	100	—	unknown	20:35–05:55 (good, 9.33 h)	79.2° 02:00	9.35	2%	137.1°
2040-10-05 Fri	100	—	unknown	20:30–05:55 (good, 9.42 h)	79.2° 01:55	9.4	0%	147.3°
2040-10-06 Sat	100	—	unknown	20:30–05:55 (good, 9.42 h)	79.2° 01:50	9.44	1%	155.5°
2040-10-07 Sun	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.2° 01:50	9.49	3%	158.8°
2040-10-08 Mon	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.2° 01:45	9.54	8%	154.7°
2040-10-09 Tue	100	—	unknown	20:25–06:00 (good, 9.58 h)	79.2° 01:40	9.58	15%	145.6°
2040-10-10 Wed	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:35	9.63	24%	134.2°
2040-10-11 Thu	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:35	9.67	34%	121.9°
2040-10-12 Fri	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:30	9.72	45%	109.1°
2040-10-13 Sat	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:25	9.76	56%	95.9°
2040-10-14 Sun	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:20	9.8	68%	82.7°
2040-10-15 Mon	100	—	unknown	21:05–06:05 (good, 9.0 h)	79.2° 01:15	9.85	78%	69.5°
2040-10-16 Tue	97	—	unknown	00:15–06:05 (good, 5.83 h)	79.2° 01:15	9.89	87%	56.5°
2040-10-17 Wed	87	—	unknown	05:10–06:05 (good, 0.92 h)	79.2° 01:10	9.93	93%	44.0°
2040-10-18 Thu	48	—	unknown	20:10–06:10 (marginal, 10.0 h)	79.2° 01:05	9.98	98%	32.7°
2040-10-19 Fri	34	—	unknown	02:35–06:10 (marginal, 3.58 h)	79.2° 01:00	10.02	100%	24.1°
2040-10-20 Sat	35	—	unknown	20:05–23:40 (marginal, 3.58 h)	79.2° 00:55	10.06	99%	21.3°
2040-10-21 Sun	40	—	unknown	20:05–00:30 (marginal, 4.42 h)	79.2° 00:55	10.1	97%	25.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-09-22&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.