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: 12-15 (88), 12-16 (88), 12-17 (87), 12-14 (86), 12-18 (85) — by astronomy; check the weather when the night is within four days.

2038-12-11astronomy score per night — click a bar for that night2039-01-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-11 Sat	59	—	unknown	18:35–21:20 (good, 2.75 h)	87.2° 16:00	11.46	100%	97.5°
2038-12-12 Sun	65	—	unknown	18:35–21:45 (good, 3.17 h)	87.2° 15:55	11.47	99%	102.8°
2038-12-13 Mon	71	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:50	11.48	96%	107.6°
2038-12-14 Tue	86	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:50	11.49	90%	111.8°
2038-12-15 Wed	88	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:45	11.49	84%	115.1°
2038-12-16 Thu	88	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:40	11.5	75%	117.1°
2038-12-17 Fri	87	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:35	11.5	66%	117.6°
2038-12-18 Sat	85	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:30	11.5	55%	116.6°
2038-12-19 Sun	84	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:30	11.51	44%	113.9°
2038-12-20 Mon	82	—	unknown	18:35–21:45 (good, 3.17 h)	87.2° 15:25	11.51	33%	109.8°
2038-12-21 Tue	78	—	unknown	18:35–21:40 (good, 3.08 h)	87.2° 15:20	11.51	23%	104.4°
2038-12-22 Wed	76	—	unknown	18:35–21:35 (good, 3.0 h)	87.2° 15:15	11.51	14%	98.1°
2038-12-23 Thu	74	—	unknown	18:40–21:35 (good, 2.92 h)	87.2° 15:10	11.51	6%	91.4°
2038-12-24 Fri	72	—	unknown	18:40–21:30 (good, 2.83 h)	87.2° 15:10	11.5	2%	84.5°
2038-12-25 Sat	70	—	unknown	18:40–21:25 (good, 2.75 h)	87.2° 15:05	11.5	0%	77.9°
2038-12-26 Sun	68	—	unknown	18:40–21:20 (good, 2.67 h)	87.2° 15:00	11.5	1%	72.1°
2038-12-27 Mon	66	—	unknown	18:40–21:15 (good, 2.58 h)	87.2° 14:55	11.49	5%	67.4°
2038-12-28 Tue	61	—	unknown	18:40–21:15 (good, 2.58 h)	87.2° 14:55	11.48	11%	64.2°
2038-12-29 Wed	55	—	unknown	18:40–21:10 (good, 2.5 h)	87.2° 14:50	11.48	18%	62.6°
2038-12-30 Thu	48	—	unknown	18:40–20:55 (good, 2.25 h)	87.2° 14:45	11.47	27%	62.5°
2038-12-31 Fri	40	—	unknown	18:45–20:45 (good, 2.0 h)	87.2° 14:40	11.46	37%	64.0°
2039-01-01 Sat	35	—	unknown	18:45–20:35 (good, 1.83 h)	87.2° 14:35	11.45	46%	66.6°
2039-01-02 Sun	30	—	unknown	18:45–20:20 (good, 1.58 h)	87.2° 14:35	11.44	56%	70.3°
2039-01-03 Mon	27	—	unknown	18:45–19:40 (good, 0.92 h)	87.2° 14:30	11.43	65%	74.6°
2039-01-04 Tue	25	—	unknown	18:45–19:15 (good, 0.5 h)	87.2° 14:25	11.42	74%	79.6°
2039-01-05 Wed	23	—	unknown	18:45–19:10 (good, 0.42 h)	87.2° 14:20	11.4	82%	84.9°
2039-01-06 Thu	23	—	unknown	18:50–19:15 (good, 0.42 h)	87.2° 14:15	11.39	88%	90.4°
2039-01-07 Fri	24	—	unknown	18:50–19:35 (good, 0.75 h)	87.2° 14:15	11.38	94%	95.9°
2039-01-08 Sat	25	—	unknown	18:50–19:55 (good, 1.08 h)	87.2° 14:10	11.36	98%	101.3°
2039-01-09 Sun	27	—	unknown	18:50–20:00 (good, 1.17 h)	87.2° 14:05	11.34	100%	106.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-11&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.