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: 09-18 (100), 09-19 (100), 09-20 (100), 09-21 (100), 09-22 (100) — by astronomy; check the weather when the night is within four days.

2039-09-18astronomy score per night — click a bar for that night2039-10-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-09-18 Sun	100	—	unknown	21:40–05:35 (good, 7.92 h)	79.2° 03:05	8.52	1%	141.9°
2039-09-19 Mon	100	—	unknown	21:35–05:35 (good, 8.0 h)	79.2° 03:00	8.57	3%	151.6°
2039-09-20 Tue	100	—	unknown	21:30–05:35 (good, 8.08 h)	79.2° 03:00	8.62	8%	157.0°
2039-09-21 Wed	100	—	unknown	21:25–05:35 (good, 8.17 h)	79.2° 02:55	8.68	16%	155.0°
2039-09-22 Thu	100	—	unknown	21:25–05:40 (good, 8.25 h)	79.2° 02:50	8.73	25%	146.7°
2039-09-23 Fri	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:45	8.78	36%	135.5°
2039-09-24 Sat	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:40	8.83	47%	123.3°
2039-09-25 Sun	100	—	unknown	21:20–05:40 (good, 8.33 h)	79.2° 02:40	8.88	58%	110.6°
2039-09-26 Mon	100	—	unknown	21:20–05:45 (good, 8.42 h)	79.2° 02:35	8.93	69%	97.8°
2039-09-27 Tue	100	—	unknown	21:30–05:45 (good, 8.25 h)	79.2° 02:30	8.98	79%	85.0°
2039-09-28 Wed	100	—	unknown	22:35–05:45 (good, 7.17 h)	79.2° 02:25	9.03	87%	72.4°
2039-09-29 Thu	99	—	unknown	01:35–05:45 (good, 4.17 h)	79.2° 02:25	9.08	94%	60.1°
2039-09-30 Fri	61	—	unknown	04:45–05:45 (good, 1.0 h)	79.2° 02:20	9.12	98%	48.4°
2039-10-01 Sat	48	—	unknown	20:45–05:50 (marginal, 9.08 h)	79.2° 02:15	9.17	100%	37.6°
2039-10-02 Sun	32	—	unknown	20:40–01:05 (marginal, 4.42 h)	79.2° 02:10	9.22	100%	28.6°
2039-10-03 Mon	35	—	unknown	20:35–01:30 (marginal, 4.92 h)	79.2° 02:05	9.27	97%	23.3°
2039-10-04 Tue	42	—	unknown	20:35–05:50 (marginal, 9.25 h)	79.2° 02:05	9.32	93%	23.7°
2039-10-05 Wed	71	—	unknown	20:30–20:50 (good, 0.33 h)	79.2° 02:00	9.36	87%	29.5°
2039-10-06 Thu	83	—	unknown	20:30–21:20 (good, 0.83 h)	79.2° 01:55	9.41	80%	38.0°
2039-10-07 Fri	87	—	unknown	20:30–01:45 (good, 5.25 h)	79.2° 01:50	9.46	72%	47.8°
2039-10-08 Sat	93	—	unknown	20:25–04:55 (good, 8.5 h)	79.2° 01:45	9.5	64%	58.1°
2039-10-09 Sun	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.2° 01:45	9.55	54%	68.8°
2039-10-10 Mon	100	—	unknown	20:25–06:00 (good, 9.58 h)	79.2° 01:40	9.59	45%	79.7°
2039-10-11 Tue	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:35	9.64	35%	90.9°
2039-10-12 Wed	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:30	9.68	26%	102.4°
2039-10-13 Thu	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:30	9.73	18%	114.1°
2039-10-14 Fri	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:25	9.77	10%	125.8°
2039-10-15 Sat	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:20	9.81	5%	137.4°
2039-10-16 Sun	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:15	9.86	1%	148.1°
2039-10-17 Mon	100	—	unknown	20:10–06:05 (good, 9.92 h)	79.2° 01:10	9.9	0%	155.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-09-18&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.