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: 12-04 (100), 12-05 (100), 12-06 (100), 12-07 (100), 12-08 (100) — by astronomy; check the weather when the night is within four days.

2039-11-20astronomy score per night — click a bar for that night2039-12-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-11-20 Sun	93	—	unknown	18:35–23:45 (good, 5.17 h)	87.2° 17:25	11.09	29%	68.2°
2039-11-21 Mon	86	—	unknown	18:35–23:40 (good, 5.08 h)	87.2° 17:20	11.12	39%	64.8°
2039-11-22 Tue	79	—	unknown	18:35–23:20 (good, 4.75 h)	87.2° 17:15	11.14	50%	63.1°
2039-11-23 Wed	70	—	unknown	18:35–23:05 (good, 4.5 h)	87.2° 17:10	11.16	61%	62.9°
2039-11-24 Thu	60	—	unknown	18:35–21:45 (good, 3.17 h)	87.2° 17:05	11.19	71%	64.3°
2039-11-25 Fri	53	—	unknown	18:35–20:35 (good, 2.0 h)	87.2° 17:05	11.21	80%	67.0°
2039-11-26 Sat	49	—	unknown	18:35–20:05 (good, 1.5 h)	87.2° 17:00	11.23	87%	70.7°
2039-11-27 Sun	49	—	unknown	18:35–20:05 (good, 1.5 h)	87.2° 16:55	11.25	93%	75.2°
2039-11-28 Mon	51	—	unknown	18:35–20:20 (good, 1.75 h)	87.2° 16:50	11.27	97%	80.2°
2039-11-29 Tue	56	—	unknown	18:35–20:45 (good, 2.17 h)	87.2° 16:50	11.29	99%	85.5°
2039-11-30 Wed	63	—	unknown	18:35–21:20 (good, 2.75 h)	87.2° 16:45	11.31	100%	91.0°
2039-12-01 Thu	70	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 16:40	11.33	99%	96.4°
2039-12-02 Fri	79	—	unknown	18:35–22:25 (good, 3.83 h)	87.2° 16:35	11.35	96%	101.5°
2039-12-03 Sat	97	—	unknown	18:35–22:30 (good, 3.92 h)	87.2° 16:30	11.36	91%	106.2°
2039-12-04 Sun	100	—	unknown	18:35–22:30 (good, 3.92 h)	87.2° 16:30	11.38	85%	110.4°
2039-12-05 Mon	100	—	unknown	18:35–22:35 (good, 4.0 h)	87.2° 16:25	11.39	77%	113.7°
2039-12-06 Tue	100	—	unknown	18:35–22:35 (good, 4.0 h)	87.2° 16:20	11.41	69%	116.0°
2039-12-07 Wed	100	—	unknown	18:35–22:35 (good, 4.0 h)	87.2° 16:15	11.42	59%	117.1°
2039-12-08 Thu	100	—	unknown	18:35–22:35 (good, 4.0 h)	87.2° 16:10	11.43	49%	116.9°
2039-12-09 Fri	100	—	unknown	18:35–22:30 (good, 3.92 h)	87.2° 16:10	11.44	39%	115.2°
2039-12-10 Sat	100	—	unknown	18:35–22:25 (good, 3.83 h)	87.2° 16:05	11.45	29%	112.0°
2039-12-11 Sun	99	—	unknown	18:35–22:20 (good, 3.75 h)	87.2° 16:00	11.46	19%	107.5°
2039-12-12 Mon	97	—	unknown	18:35–22:15 (good, 3.67 h)	87.2° 15:55	11.47	11%	101.9°
2039-12-13 Tue	96	—	unknown	18:35–22:15 (good, 3.67 h)	87.2° 15:55	11.48	5%	95.5°
2039-12-14 Wed	94	—	unknown	18:35–22:10 (good, 3.58 h)	87.2° 15:50	11.48	1%	88.6°
2039-12-15 Thu	92	—	unknown	18:35–22:05 (good, 3.5 h)	87.2° 15:45	11.49	0%	81.7°
2039-12-16 Fri	90	—	unknown	18:35–22:00 (good, 3.42 h)	87.2° 15:40	11.5	2%	75.3°
2039-12-17 Sat	87	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:35	11.5	8%	69.9°
2039-12-18 Sun	80	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:35	11.5	15%	65.8°
2039-12-19 Mon	71	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:30	11.51	24%	63.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-11-20&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.