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: 12-01 (100), 12-02 (100), 12-03 (100), 12-04 (100), 12-05 (100) — by astronomy; check the weather when the night is within four days.

2040-12-01astronomy score per night — click a bar for that night2040-12-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-12-01 Sat	100	—	unknown	18:35–22:55 (good, 4.33 h)	87.2° 16:35	11.34	7%	104.5°
2040-12-02 Sun	100	—	unknown	18:35–22:55 (good, 4.33 h)	87.2° 16:35	11.36	2%	98.6°
2040-12-03 Mon	100	—	unknown	18:35–22:50 (good, 4.25 h)	87.2° 16:30	11.37	0%	92.2°
2040-12-04 Tue	100	—	unknown	18:35–22:45 (good, 4.17 h)	87.2° 16:25	11.39	1%	85.5°
2040-12-05 Wed	100	—	unknown	18:35–22:40 (good, 4.08 h)	87.2° 16:20	11.4	4%	79.0°
2040-12-06 Thu	100	—	unknown	18:35–22:40 (good, 4.08 h)	87.2° 16:15	11.42	10%	73.0°
2040-12-07 Fri	95	—	unknown	18:35–22:35 (good, 4.0 h)	87.2° 16:15	11.43	18%	68.1°
2040-12-08 Sat	86	—	unknown	18:35–22:30 (good, 3.92 h)	87.2° 16:10	11.44	27%	64.6°
2040-12-09 Sun	73	—	unknown	18:35–22:15 (good, 3.67 h)	87.2° 16:05	11.45	38%	62.8°
2040-12-10 Mon	61	—	unknown	18:35–22:00 (good, 3.42 h)	87.2° 16:00	11.46	49%	62.7°
2040-12-11 Tue	51	—	unknown	18:35–21:35 (good, 3.0 h)	87.2° 16:00	11.47	60%	64.4°
2040-12-12 Wed	44	—	unknown	18:35–20:10 (good, 1.58 h)	87.2° 15:55	11.48	71%	67.5°
2040-12-13 Thu	39	—	unknown	18:35–19:30 (good, 0.92 h)	87.2° 15:50	11.48	80%	71.7°
2040-12-14 Fri	38	—	unknown	18:35–19:20 (good, 0.75 h)	87.2° 15:45	11.49	88%	76.8°
2040-12-15 Sat	39	—	unknown	18:35–19:35 (good, 1.0 h)	87.2° 15:40	11.49	94%	82.3°
2040-12-16 Sun	42	—	unknown	18:35–19:55 (good, 1.33 h)	87.2° 15:40	11.5	98%	88.0°
2040-12-17 Mon	47	—	unknown	18:35–20:30 (good, 1.92 h)	87.2° 15:35	11.5	100%	93.8°
2040-12-18 Tue	52	—	unknown	18:35–21:05 (good, 2.5 h)	87.2° 15:30	11.51	100%	99.3°
2040-12-19 Wed	57	—	unknown	18:35–21:20 (good, 2.75 h)	87.2° 15:25	11.51	98%	104.4°
2040-12-20 Thu	62	—	unknown	18:35–21:20 (good, 2.75 h)	87.2° 15:20	11.51	94%	108.9°
2040-12-21 Fri	72	—	unknown	18:35–21:25 (good, 2.83 h)	87.2° 15:20	11.51	89%	112.6°
2040-12-22 Sat	73	—	unknown	18:35–21:25 (good, 2.83 h)	87.2° 15:15	11.51	83%	115.4°
2040-12-23 Sun	72	—	unknown	18:40–21:30 (good, 2.83 h)	87.2° 15:10	11.5	75%	117.1°
2040-12-24 Mon	70	—	unknown	18:40–21:25 (good, 2.75 h)	87.2° 15:05	11.5	67%	117.5°
2040-12-25 Tue	69	—	unknown	18:40–21:25 (good, 2.75 h)	87.2° 15:05	11.5	58%	116.7°
2040-12-26 Wed	67	—	unknown	18:40–21:20 (good, 2.67 h)	87.2° 15:00	11.49	48%	114.5°
2040-12-27 Thu	65	—	unknown	18:40–21:15 (good, 2.58 h)	87.2° 14:55	11.49	38%	111.2°
2040-12-28 Fri	63	—	unknown	18:40–21:10 (good, 2.5 h)	87.2° 14:50	11.48	28%	106.7°
2040-12-29 Sat	60	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 14:45	11.47	19%	101.3°
2040-12-30 Sun	59	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 14:45	11.47	11%	95.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-12-01&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.