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: 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100), 08-22 (100) — by astronomy; check the weather when the night is within four days.

2038-08-13astronomy score per night — click a bar for that night2038-09-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-08-13 Fri	65	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:50	6.53	99%	64.8°
2038-08-14 Sat	64	—	unknown	22:10–23:35 (good, 1.42 h)	87.2° 00:50	6.59	100%	62.6°
2038-08-15 Sun	66	—	unknown	22:10–23:50 (good, 1.67 h)	87.2° 00:45	6.65	99%	61.8°
2038-08-16 Mon	70	—	unknown	22:05–00:35 (good, 2.5 h)	87.2° 00:40	6.7	96%	62.6°
2038-08-17 Tue	75	—	unknown	22:05–01:50 (good, 3.75 h)	87.2° 00:35	6.76	91%	64.7°
2038-08-18 Wed	100	—	unknown	22:05–03:35 (good, 5.5 h)	87.2° 00:30	6.82	85%	67.9°
2038-08-19 Thu	100	—	unknown	22:00–04:25 (good, 6.42 h)	87.2° 00:30	6.88	77%	72.0°
2038-08-20 Fri	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.94	69%	76.7°
2038-08-21 Sat	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.2° 00:20	6.99	60%	82.0°
2038-08-22 Sun	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.05	50%	87.5°
2038-08-23 Mon	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:10	7.11	41%	93.1°
2038-08-24 Tue	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:10	7.16	31%	98.8°
2038-08-25 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.22	22%	104.3°
2038-08-26 Thu	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 00:00	7.28	14%	109.3°
2038-08-27 Fri	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.33	8%	113.5°
2038-08-28 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:50	7.39	3%	116.6°
2038-08-29 Sun	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:50	7.45	0%	118.1°
2038-08-30 Mon	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:45	7.5	0%	117.8°
2038-08-31 Tue	100	—	unknown	21:35–05:10 (good, 7.58 h)	87.2° 23:40	7.56	3%	115.5°
2038-09-01 Wed	100	—	unknown	21:35–05:10 (good, 7.58 h)	87.2° 23:35	7.62	9%	111.6°
2038-09-02 Thu	100	—	unknown	21:35–05:15 (good, 7.67 h)	87.2° 23:35	7.67	17%	106.3°
2038-09-03 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:30	7.73	26%	100.2°
2038-09-04 Sat	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:25	7.78	37%	93.6°
2038-09-05 Sun	100	—	unknown	21:25–05:15 (good, 7.83 h)	87.2° 23:20	7.84	48%	86.9°
2038-09-06 Mon	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.89	60%	80.6°
2038-09-07 Tue	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.95	70%	74.7°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-08-13&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.