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 North America Nebula: 08-19 (100), 08-20 (100), 08-21 (100), 08-22 (100), 08-23 (100) — by astronomy; check the weather when the night is within four days.

2042-08-19astronomy score per night — click a bar for that night2042-09-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-08-19 Tue	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.88	16%	115.9°
2042-08-20 Wed	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.94	23%	112.5°
2042-08-21 Thu	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.2° 00:20	6.99	32%	108.1°
2042-08-22 Fri	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.05	41%	103.0°
2042-08-23 Sat	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:10	7.11	50%	97.4°
2042-08-24 Sun	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:10	7.17	60%	91.4°
2042-08-25 Mon	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.22	70%	85.2°
2042-08-26 Tue	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 00:00	7.28	79%	79.0°
2042-08-27 Wed	99	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.34	87%	73.1°
2042-08-28 Thu	90	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.39	94%	67.8°
2042-08-29 Fri	64	—	unknown	01:30–04:00 (good, 2.5 h)	87.2° 23:50	7.45	98%	63.7°
2042-08-30 Sat	63	—	unknown	21:40–22:35 (good, 0.92 h)	87.2° 23:45	7.51	100%	61.1°
2042-08-31 Sun	66	—	unknown	21:35–22:50 (good, 1.25 h)	87.2° 23:40	7.56	99%	60.6°
2042-09-01 Mon	69	—	unknown	21:35–23:35 (good, 2.0 h)	87.2° 23:35	7.62	95%	62.2°
2042-09-02 Tue	75	—	unknown	21:35–01:15 (good, 3.67 h)	87.2° 23:35	7.67	88%	65.8°
2042-09-03 Wed	100	—	unknown	21:30–03:00 (good, 5.5 h)	87.2° 23:30	7.73	80%	70.9°
2042-09-04 Thu	100	—	unknown	21:30–04:10 (good, 6.67 h)	87.2° 23:25	7.78	70%	77.0°
2042-09-05 Fri	100	—	unknown	21:25–05:10 (good, 7.75 h)	87.2° 23:20	7.84	59%	83.6°
2042-09-06 Sat	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.89	48%	90.4°
2042-09-07 Sun	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.95	37%	96.9°
2042-09-08 Mon	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.2° 23:10	8.0	27%	103.1°
2042-09-09 Tue	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.2° 23:05	8.06	18%	108.5°
2042-09-10 Wed	100	—	unknown	21:15–05:20 (good, 8.08 h)	87.2° 23:00	8.11	11%	113.1°
2042-09-11 Thu	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 22:55	8.17	6%	116.6°
2042-09-12 Fri	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 22:55	8.22	2%	118.7°
2042-09-13 Sat	100	—	unknown	21:10–05:10 (good, 8.0 h)	87.2° 22:50	8.27	0%	119.5°
2042-09-14 Sun	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.2° 22:45	8.33	0%	118.8°
2042-09-15 Mon	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.38	2%	116.8°
2042-09-16 Tue	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.43	6%	113.7°
2042-09-17 Wed	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.2° 22:35	8.48	11%	109.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-08-19&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.