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: 09-16 (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.

2038-09-08astronomy score per night — click a bar for that night2038-10-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-09-08 Wed	98	—	unknown	21:20–05:20 (good, 8.0 h)	87.2° 23:10	8.0	79%	69.7°
2038-09-09 Thu	90	—	unknown	21:20–05:25 (good, 8.08 h)	87.2° 23:05	8.06	87%	65.8°
2038-09-10 Fri	82	—	unknown	21:15–05:20 (good, 8.08 h)	87.2° 23:00	8.11	93%	63.1°
2038-09-11 Sat	63	—	unknown	21:15–22:10 (good, 0.92 h)	87.2° 22:55	8.16	97%	61.9°
2038-09-12 Sun	64	—	unknown	21:15–22:10 (good, 0.92 h)	87.2° 22:55	8.22	100%	62.2°
2038-09-13 Mon	66	—	unknown	21:10–22:40 (good, 1.5 h)	87.2° 22:50	8.27	100%	63.8°
2038-09-14 Tue	70	—	unknown	21:10–23:30 (good, 2.33 h)	87.2° 22:45	8.32	98%	66.7°
2038-09-15 Wed	74	—	unknown	21:10–00:55 (good, 3.75 h)	87.2° 22:40	8.38	94%	70.5°
2038-09-16 Thu	100	—	unknown	21:05–02:00 (good, 4.92 h)	87.2° 22:40	8.43	89%	75.0°
2038-09-17 Fri	100	—	unknown	21:05–02:50 (good, 5.75 h)	87.2° 22:35	8.48	83%	80.1°
2038-09-18 Sat	100	—	unknown	21:00–03:45 (good, 6.75 h)	87.2° 22:30	8.53	75%	85.5°
2038-09-19 Sun	100	—	unknown	21:00–04:15 (good, 7.25 h)	87.2° 22:25	8.59	67%	91.1°
2038-09-20 Mon	100	—	unknown	21:00–04:20 (good, 7.33 h)	87.2° 22:20	8.64	57%	96.7°
2038-09-21 Tue	100	—	unknown	20:55–04:25 (good, 7.5 h)	87.2° 22:20	8.69	48%	102.1°
2038-09-22 Wed	100	—	unknown	20:55–04:25 (good, 7.5 h)	87.2° 22:15	8.74	38%	107.2°
2038-09-23 Thu	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.2° 22:10	8.79	28%	111.7°
2038-09-24 Fri	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.2° 22:05	8.84	19%	115.3°
2038-09-25 Sat	100	—	unknown	20:50–04:20 (good, 7.5 h)	87.2° 22:00	8.89	11%	117.5°
2038-09-26 Sun	100	—	unknown	20:45–04:20 (good, 7.58 h)	87.2° 22:00	8.94	5%	118.1°
2038-09-27 Mon	100	—	unknown	20:45–04:15 (good, 7.5 h)	87.2° 21:55	8.99	1%	116.7°
2038-09-28 Tue	100	—	unknown	20:45–04:10 (good, 7.42 h)	87.2° 21:50	9.04	0%	113.4°
2038-09-29 Wed	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.09	2%	108.6°
2038-09-30 Thu	100	—	unknown	20:40–04:05 (good, 7.42 h)	87.2° 21:45	9.14	7%	102.6°
2038-10-01 Fri	100	—	unknown	20:40–04:00 (good, 7.33 h)	87.2° 21:40	9.18	14%	95.9°
2038-10-02 Sat	100	—	unknown	20:35–03:55 (good, 7.33 h)	87.2° 21:35	9.23	23%	89.0°
2038-10-03 Sun	100	—	unknown	20:35–03:50 (good, 7.25 h)	87.2° 21:30	9.28	34%	82.4°
2038-10-04 Mon	100	—	unknown	20:35–03:45 (good, 7.17 h)	87.2° 21:25	9.33	45%	76.3°
2038-10-05 Tue	100	—	unknown	20:30–03:45 (good, 7.25 h)	87.2° 21:25	9.37	56%	71.0°
2038-10-06 Wed	92	—	unknown	20:30–03:40 (good, 7.17 h)	87.2° 21:20	9.42	66%	66.8°
2038-10-07 Thu	85	—	unknown	20:25–03:35 (good, 7.17 h)	87.2° 21:15	9.47	75%	63.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-09-08&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.