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: 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100) — by astronomy; check the weather when the night is within four days.

2046-09-13astronomy score per night — click a bar for that night2046-10-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-09-13 Thu	56	—	unknown	21:10–05:30 (marginal, 8.33 h)	87.2° 22:50	8.27	98%	54.8°
2046-09-14 Fri	57	—	unknown	21:10–05:20 (marginal, 8.17 h)	87.2° 22:45	8.33	100%	54.4°
2046-09-15 Sat	59	—	unknown	21:05–05:10 (marginal, 8.08 h)	87.2° 22:40	8.38	100%	55.7°
2046-09-16 Sun	63	—	unknown	21:05–21:45 (good, 0.67 h)	87.2° 22:40	8.43	97%	58.6°
2046-09-17 Mon	68	—	unknown	21:05–22:55 (good, 1.83 h)	87.2° 22:35	8.49	94%	62.9°
2046-09-18 Tue	74	—	unknown	21:00–00:45 (good, 3.75 h)	87.2° 22:30	8.54	88%	68.3°
2046-09-19 Wed	80	—	unknown	21:00–02:10 (good, 5.17 h)	87.2° 22:25	8.59	82%	74.5°
2046-09-20 Thu	100	—	unknown	21:00–03:15 (good, 6.25 h)	87.2° 22:20	8.64	73%	81.2°
2046-09-21 Fri	100	—	unknown	20:55–04:10 (good, 7.25 h)	87.2° 22:20	8.69	64%	88.3°
2046-09-22 Sat	100	—	unknown	20:55–04:15 (good, 7.33 h)	87.2° 22:15	8.74	54%	95.7°
2046-09-23 Sun	100	—	unknown	20:50–04:20 (good, 7.5 h)	87.2° 22:10	8.79	44%	103.0°
2046-09-24 Mon	100	—	unknown	20:50–04:20 (good, 7.5 h)	87.2° 22:05	8.84	33%	110.1°
2046-09-25 Tue	100	—	unknown	20:50–04:20 (good, 7.5 h)	87.1° 22:00	8.89	23%	116.6°
2046-09-26 Wed	100	—	unknown	20:45–04:20 (good, 7.58 h)	87.2° 22:00	8.94	14%	121.7°
2046-09-27 Thu	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 21:55	8.99	7%	125.0°
2046-09-28 Fri	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 21:50	9.04	2%	125.6°
2046-09-29 Sat	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.09	0%	123.5°
2046-09-30 Sun	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.14	1%	118.7°
2046-10-01 Mon	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.2° 21:40	9.19	5%	112.2°
2046-10-02 Tue	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.2° 21:35	9.24	12%	104.6°
2046-10-03 Wed	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.28	20%	96.4°
2046-10-04 Thu	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.33	30%	88.3°
2046-10-05 Fri	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.38	40%	80.5°
2046-10-06 Sat	100	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.42	51%	73.3°
2046-10-07 Sun	95	—	unknown	20:25–03:35 (good, 7.17 h)	87.2° 21:15	9.47	61%	66.9°
2046-10-08 Mon	87	—	unknown	20:25–03:30 (good, 7.08 h)	87.2° 21:10	9.52	70%	61.6°
2046-10-09 Tue	78	—	unknown	20:25–03:30 (good, 7.08 h)	87.1° 21:05	9.56	78%	57.5°
2046-10-10 Wed	59	—	unknown	20:20–04:00 (marginal, 7.67 h)	87.2° 21:05	9.61	86%	55.0°
2046-10-11 Thu	54	—	unknown	20:20–03:45 (marginal, 7.42 h)	87.2° 21:00	9.65	92%	54.2°
2046-10-12 Fri	49	—	unknown	20:20–03:30 (marginal, 7.17 h)	87.2° 20:55	9.7	96%	55.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-09-13&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.