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: 12-13 (77), 12-14 (66), 12-26 (65), 12-27 (65), 12-28 (63) — by astronomy; check the weather when the night is within four days.

2045-12-13astronomy score per night — click a bar for that night2046-01-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-12-13 Wed	77	—	unknown	18:35–22:10 (good, 3.58 h)	87.2° 15:50	11.48	26%	58.0°
2045-12-14 Thu	66	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:45	11.49	35%	55.7°
2045-12-15 Fri	56	—	unknown	18:35–21:40 (good, 3.08 h)	87.2° 15:45	11.49	44%	55.1°
2045-12-16 Sat	46	—	unknown	18:35–21:20 (good, 2.75 h)	87.2° 15:40	11.5	54%	56.2°
2045-12-17 Sun	38	—	unknown	18:35–19:40 (good, 1.08 h)	87.2° 15:35	11.5	63%	58.9°
2045-12-18 Mon	33	—	unknown	18:35–18:50 (good, 0.25 h)	87.2° 15:30	11.5	72%	63.1°
2045-12-19 Tue	31	—	unknown	18:00–22:05 (marginal, 4.08 h)	87.2° 15:25	11.51	81%	68.6°
2045-12-20 Wed	31	—	unknown	18:35–18:40 (good, 0.08 h)	87.2° 15:25	11.51	88%	75.1°
2045-12-21 Thu	33	—	unknown	18:35–19:10 (good, 0.58 h)	87.2° 15:20	11.51	94%	82.5°
2045-12-22 Fri	37	—	unknown	18:35–19:50 (good, 1.25 h)	87.2° 15:15	11.51	98%	90.3°
2045-12-23 Sat	42	—	unknown	18:40–20:40 (good, 2.0 h)	87.2° 15:10	11.5	100%	98.4°
2045-12-24 Sun	49	—	unknown	18:40–21:00 (good, 2.33 h)	87.1° 15:10	11.5	99%	106.2°
2045-12-25 Mon	56	—	unknown	18:40–21:10 (good, 2.5 h)	87.2° 15:05	11.5	95%	113.4°
2045-12-26 Tue	65	—	unknown	18:40–21:10 (good, 2.5 h)	87.2° 15:00	11.49	89%	119.2°
2045-12-27 Wed	65	—	unknown	18:40–21:15 (good, 2.58 h)	87.2° 14:55	11.49	80%	123.3°
2045-12-28 Thu	63	—	unknown	18:40–21:10 (good, 2.5 h)	87.2° 14:50	11.48	70%	125.0°
2045-12-29 Fri	61	—	unknown	18:40–21:10 (good, 2.5 h)	87.2° 14:50	11.48	59%	124.2°
2045-12-30 Sat	60	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 14:45	11.47	48%	121.1°
2045-12-31 Sun	56	—	unknown	18:45–21:00 (good, 2.25 h)	87.2° 14:40	11.46	37%	116.3°
2046-01-01 Mon	55	—	unknown	18:45–20:55 (good, 2.17 h)	87.2° 14:35	11.45	27%	110.2°
2046-01-02 Tue	54	—	unknown	18:45–20:50 (good, 2.08 h)	87.2° 14:30	11.44	18%	103.3°
2046-01-03 Wed	52	—	unknown	18:45–20:50 (good, 2.08 h)	87.2° 14:30	11.43	11%	96.0°
2046-01-04 Thu	49	—	unknown	18:45–20:45 (good, 2.0 h)	87.2° 14:25	11.41	5%	88.7°
2046-01-05 Fri	47	—	unknown	18:45–20:40 (good, 1.92 h)	87.2° 14:20	11.4	2%	81.4°
2046-01-06 Sat	45	—	unknown	18:50–20:35 (good, 1.75 h)	87.2° 14:15	11.39	0%	74.6°
2046-01-07 Sun	44	—	unknown	18:50–20:35 (good, 1.75 h)	87.1° 14:15	11.37	1%	68.4°
2046-01-08 Mon	42	—	unknown	18:50–20:30 (good, 1.67 h)	87.2° 14:10	11.36	3%	63.1°
2046-01-09 Tue	39	—	unknown	18:50–20:25 (good, 1.58 h)	87.2° 14:05	11.34	7%	58.9°
2046-01-10 Wed	35	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 14:00	11.32	12%	56.1°
2046-01-11 Thu	31	—	unknown	18:50–20:10 (good, 1.33 h)	87.2° 13:55	11.3	19%	55.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-12-13&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.