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: 09-21 (100), 09-22 (100), 09-23 (100), 10-02 (100), 10-03 (100) — by astronomy; check the weather when the night is within four days.

2042-09-21astronomy score per night — click a bar for that night2042-10-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-09-21 Sun	100	—	unknown	20:55–04:40 (good, 7.75 h)	87.2° 22:20	8.69	44%	87.4°
2042-09-22 Mon	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.2° 22:15	8.74	54%	81.4°
2042-09-23 Tue	100	—	unknown	20:50–04:30 (good, 7.67 h)	87.2° 22:10	8.79	64%	75.5°
2042-09-24 Wed	94	—	unknown	20:50–04:25 (good, 7.58 h)	87.2° 22:05	8.84	74%	70.0°
2042-09-25 Thu	85	—	unknown	20:50–04:25 (good, 7.58 h)	87.2° 22:00	8.89	83%	65.4°
2042-09-26 Fri	64	—	unknown	20:45–01:45 (good, 5.0 h)	87.2° 22:00	8.94	91%	62.1°
2042-09-27 Sat	61	—	unknown	20:45–21:10 (good, 0.42 h)	87.2° 21:55	8.99	96%	60.6°
2042-09-28 Sun	62	—	unknown	20:45–21:05 (good, 0.33 h)	87.2° 21:50	9.04	100%	61.2°
2042-09-29 Mon	65	—	unknown	20:40–21:45 (good, 1.08 h)	87.2° 21:45	9.09	100%	64.0°
2042-09-30 Tue	70	—	unknown	20:40–23:00 (good, 2.33 h)	87.2° 21:45	9.14	97%	68.7°
2042-10-01 Wed	76	—	unknown	20:40–00:45 (good, 4.08 h)	87.2° 21:40	9.19	91%	74.6°
2042-10-02 Thu	100	—	unknown	20:35–01:55 (good, 5.33 h)	87.2° 21:35	9.23	83%	81.3°
2042-10-03 Fri	100	—	unknown	20:35–03:05 (good, 6.5 h)	87.2° 21:30	9.28	73%	88.3°
2042-10-04 Sat	100	—	unknown	20:35–03:25 (good, 6.83 h)	87.2° 21:25	9.33	63%	95.1°
2042-10-05 Sun	100	—	unknown	20:30–03:30 (good, 7.0 h)	87.2° 21:25	9.38	52%	101.5°
2042-10-06 Mon	100	—	unknown	20:30–03:30 (good, 7.0 h)	87.2° 21:20	9.42	41%	107.2°
2042-10-07 Tue	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:15	9.47	32%	112.0°
2042-10-08 Wed	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.51	23%	115.8°
2042-10-09 Thu	100	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:05	9.56	15%	118.3°
2042-10-10 Fri	100	—	unknown	20:25–03:25 (good, 7.0 h)	87.2° 21:05	9.61	9%	119.4°
2042-10-11 Sat	100	—	unknown	20:20–03:20 (good, 7.0 h)	87.2° 21:00	9.65	4%	119.1°
2042-10-12 Sun	100	—	unknown	20:20–03:15 (good, 6.92 h)	87.2° 20:55	9.69	1%	117.4°
2042-10-13 Mon	100	—	unknown	20:20–03:10 (good, 6.83 h)	87.2° 20:50	9.74	0%	114.6°
2042-10-14 Tue	100	—	unknown	20:15–03:10 (good, 6.92 h)	87.2° 20:50	9.78	1%	110.7°
2042-10-15 Wed	100	—	unknown	20:15–03:05 (good, 6.83 h)	87.2° 20:45	9.83	3%	106.0°
2042-10-16 Thu	100	—	unknown	20:15–03:00 (good, 6.75 h)	87.2° 20:40	9.87	7%	100.7°
2042-10-17 Fri	100	—	unknown	20:10–02:55 (good, 6.75 h)	87.2° 20:35	9.91	13%	95.0°
2042-10-18 Sat	100	—	unknown	20:10–02:50 (good, 6.67 h)	87.2° 20:30	9.95	20%	89.1°
2042-10-19 Sun	100	—	unknown	20:10–02:50 (good, 6.67 h)	87.2° 20:30	10.0	28%	83.1°
2042-10-20 Mon	100	—	unknown	20:05–02:45 (good, 6.67 h)	87.2° 20:25	10.04	38%	77.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-09-21&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.