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: 08-12 (100), 08-13 (100), 08-14 (100), 08-15 (100), 08-16 (100) — by astronomy; check the weather when the night is within four days.

2039-08-12astronomy score per night — click a bar for that night2039-09-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-08-12 Fri	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:55	6.46	40%	87.5°
2039-08-13 Sat	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:50	6.52	30%	92.9°
2039-08-14 Sun	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:50	6.58	22%	98.3°
2039-08-15 Mon	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:45	6.63	15%	103.4°
2039-08-16 Tue	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:40	6.69	9%	108.1°
2039-08-17 Wed	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.75	4%	112.1°
2039-08-18 Thu	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.81	1%	115.2°
2039-08-19 Fri	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.86	0%	117.1°
2039-08-20 Sat	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.92	1%	117.5°
2039-08-21 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:20	6.98	5%	116.4°
2039-08-22 Mon	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.04	11%	113.7°
2039-08-23 Tue	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.09	18%	109.7°
2039-08-24 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:10	7.15	28%	104.6°
2039-08-25 Thu	100	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.21	38%	98.6°
2039-08-26 Fri	100	—	unknown	21:50–05:05 (good, 7.25 h)	87.2° 00:00	7.26	50%	92.3°
2039-08-27 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.32	61%	85.7°
2039-08-28 Sun	100	—	unknown	21:45–05:05 (good, 7.33 h)	87.2° 23:55	7.38	72%	79.4°
2039-08-29 Mon	100	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:50	7.43	82%	73.5°
2039-08-30 Tue	93	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:45	7.49	90%	68.6°
2039-08-31 Wed	85	—	unknown	21:40–05:10 (good, 7.5 h)	87.2° 23:40	7.55	95%	65.0°
2039-09-01 Thu	64	—	unknown	21:35–22:55 (good, 1.33 h)	87.2° 23:40	7.6	99%	62.9°
2039-09-02 Fri	65	—	unknown	21:35–22:55 (good, 1.33 h)	87.2° 23:35	7.66	100%	62.5°
2039-09-03 Sat	69	—	unknown	21:30–23:30 (good, 2.0 h)	87.2° 23:30	7.71	98%	63.8°
2039-09-04 Sun	73	—	unknown	21:30–00:35 (good, 3.08 h)	87.2° 23:25	7.77	95%	66.5°
2039-09-05 Mon	100	—	unknown	21:30–02:15 (good, 4.75 h)	87.2° 23:20	7.82	89%	70.3°
2039-09-06 Tue	100	—	unknown	21:25–03:05 (good, 5.67 h)	87.2° 23:20	7.88	82%	74.9°
2039-09-07 Wed	100	—	unknown	21:25–04:00 (good, 6.58 h)	87.2° 23:15	7.93	74%	80.0°
2039-09-08 Thu	100	—	unknown	21:20–04:55 (good, 7.58 h)	87.2° 23:10	7.99	65%	85.4°
2039-09-09 Fri	100	—	unknown	21:20–05:05 (good, 7.75 h)	87.2° 23:05	8.04	56%	90.9°
2039-09-10 Sat	100	—	unknown	21:20–05:05 (good, 7.75 h)	87.2° 23:00	8.1	47%	96.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-08-12&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.