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: 09-16 (100), 09-17 (100), 09-18 (100), 09-19 (100), 09-20 (100) — by astronomy; check the weather when the night is within four days.

2042-09-16astronomy score per night — click a bar for that night2042-10-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-09-16 Tue	100	—	unknown	21:45–05:30 (good, 7.75 h)	79.2° 03:15	8.43	6%	158.1°
2042-09-17 Wed	100	—	unknown	21:40–05:35 (good, 7.92 h)	79.2° 03:10	8.48	11%	162.1°
2042-09-18 Thu	100	—	unknown	21:40–05:35 (good, 7.92 h)	79.2° 03:05	8.54	18%	159.2°
2042-09-19 Fri	100	—	unknown	21:35–05:35 (good, 8.0 h)	79.2° 03:00	8.59	25%	151.4°
2042-09-20 Sat	100	—	unknown	21:30–05:35 (good, 8.08 h)	79.2° 02:55	8.64	34%	141.5°
2042-09-21 Sun	100	—	unknown	21:30–05:35 (good, 8.08 h)	79.2° 02:55	8.69	44%	130.5°
2042-09-22 Mon	100	—	unknown	21:25–05:40 (good, 8.25 h)	79.2° 02:50	8.74	54%	118.9°
2042-09-23 Tue	100	—	unknown	21:30–05:40 (good, 8.17 h)	79.2° 02:45	8.79	64%	106.7°
2042-09-24 Wed	100	—	unknown	21:30–05:40 (good, 8.17 h)	79.2° 02:40	8.84	74%	94.1°
2042-09-25 Thu	100	—	unknown	21:50–05:40 (good, 7.83 h)	79.2° 02:40	8.89	83%	80.9°
2042-09-26 Fri	100	—	unknown	23:35–05:45 (good, 6.17 h)	79.2° 02:35	8.94	91%	67.4°
2042-09-27 Sat	94	—	unknown	03:45–05:45 (good, 2.0 h)	79.2° 02:30	8.99	96%	53.7°
2042-09-28 Sun	51	—	unknown	20:55–05:45 (marginal, 8.83 h)	79.2° 02:25	9.04	100%	40.1°
2042-09-29 Mon	30	—	unknown	21:00–00:25 (marginal, 3.42 h)	79.2° 02:20	9.09	100%	27.5°
2042-09-30 Tue	31	—	unknown	20:45–01:00 (marginal, 4.25 h)	79.2° 02:20	9.14	97%	18.9°
2042-10-01 Wed	40	—	unknown	20:40–05:50 (marginal, 9.17 h)	79.2° 02:15	9.19	91%	20.0°
2042-10-02 Thu	63	—	unknown	20:45–20:50 (good, 0.08 h)	79.2° 02:10	9.23	83%	29.5°
2042-10-03 Fri	82	—	unknown	20:40–00:40 (good, 4.0 h)	79.2° 02:05	9.28	73%	41.6°
2042-10-04 Sat	89	—	unknown	20:35–04:55 (good, 8.33 h)	79.2° 02:00	9.33	63%	54.2°
2042-10-05 Sun	97	—	unknown	20:30–05:55 (good, 9.42 h)	79.2° 02:00	9.38	52%	66.9°
2042-10-06 Mon	100	—	unknown	20:30–05:55 (good, 9.42 h)	79.2° 01:55	9.42	41%	79.3°
2042-10-07 Tue	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.2° 01:50	9.47	32%	91.4°
2042-10-08 Wed	100	—	unknown	20:25–05:55 (good, 9.5 h)	79.2° 01:45	9.51	23%	103.2°
2042-10-09 Thu	100	—	unknown	20:25–06:00 (good, 9.58 h)	79.2° 01:45	9.56	15%	114.8°
2042-10-10 Fri	100	—	unknown	20:25–06:00 (good, 9.58 h)	79.2° 01:40	9.61	9%	126.1°
2042-10-11 Sat	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:35	9.65	4%	137.0°
2042-10-12 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:30	9.69	1%	147.3°
2042-10-13 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	79.2° 01:25	9.74	0%	156.2°
2042-10-14 Tue	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:25	9.78	1%	161.6°
2042-10-15 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	79.2° 01:20	9.83	3%	160.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-09-16&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.