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: 12-16 (86), 12-17 (86), 12-18 (86), 12-19 (84), 12-15 (82) — by astronomy; check the weather when the night is within four days.

2027-12-04astronomy score per night — click a bar for that night2028-01-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-12-04 Sat	78	—	unknown	18:35–22:35 (good, 4.0 h)	87.2° 16:30	11.38	38%	56.0°
2027-12-05 Sun	65	—	unknown	18:35–22:20 (good, 3.75 h)	87.2° 16:25	11.39	47%	54.4°
2027-12-06 Mon	53	—	unknown	18:35–21:50 (good, 3.25 h)	87.3° 16:20	11.4	57%	54.6°
2027-12-07 Tue	44	—	unknown	18:35–19:55 (good, 1.33 h)	87.2° 16:15	11.42	66%	56.5°
2027-12-08 Wed	38	—	unknown	18:35–19:00 (good, 0.42 h)	87.2° 16:10	11.43	75%	60.2°
2027-12-09 Thu	35	—	unknown	18:35–22:45 (marginal, 4.17 h)	87.2° 16:10	11.44	83%	65.3°
2027-12-10 Fri	35	—	unknown	18:35–18:50 (good, 0.25 h)	87.3° 16:05	11.45	90%	71.8°
2027-12-11 Sat	39	—	unknown	18:35–19:20 (good, 0.75 h)	87.3° 16:00	11.46	96%	79.2°
2027-12-12 Sun	46	—	unknown	18:35–20:05 (good, 1.5 h)	87.2° 15:55	11.47	99%	87.2°
2027-12-13 Mon	55	—	unknown	18:35–21:00 (good, 2.42 h)	87.2° 15:55	11.48	100%	95.6°
2027-12-14 Tue	64	—	unknown	18:35–21:40 (good, 3.08 h)	87.2° 15:50	11.48	98%	103.8°
2027-12-15 Wed	82	—	unknown	18:35–21:45 (good, 3.17 h)	87.3° 15:45	11.49	93%	111.5°
2027-12-16 Thu	86	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:40	11.5	86%	118.0°
2027-12-17 Fri	86	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:35	11.5	77%	122.9°
2027-12-18 Sat	86	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:35	11.5	66%	125.5°
2027-12-19 Sun	84	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:30	11.51	55%	125.5°
2027-12-20 Mon	82	—	unknown	18:35–21:45 (good, 3.17 h)	87.3° 15:25	11.51	44%	123.2°
2027-12-21 Tue	79	—	unknown	18:35–21:40 (good, 3.08 h)	87.2° 15:20	11.51	33%	119.0°
2027-12-22 Wed	77	—	unknown	18:35–21:35 (good, 3.0 h)	87.2° 15:15	11.51	24%	113.3°
2027-12-23 Thu	74	—	unknown	18:40–21:35 (good, 2.92 h)	87.2° 15:15	11.51	15%	106.6°
2027-12-24 Fri	72	—	unknown	18:40–21:30 (good, 2.83 h)	87.3° 15:10	11.5	8%	99.4°
2027-12-25 Sat	70	—	unknown	18:40–21:25 (good, 2.75 h)	87.3° 15:05	11.5	4%	92.0°
2027-12-26 Sun	68	—	unknown	18:40–21:20 (good, 2.67 h)	87.2° 15:00	11.5	1%	84.7°
2027-12-27 Mon	67	—	unknown	18:40–21:20 (good, 2.67 h)	87.2° 15:00	11.49	0%	77.6°
2027-12-28 Tue	65	—	unknown	18:40–21:15 (good, 2.58 h)	87.2° 14:55	11.49	1%	71.0°
2027-12-29 Wed	63	—	unknown	18:40–21:10 (good, 2.5 h)	87.3° 14:50	11.48	4%	65.2°
2027-12-30 Thu	58	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 14:45	11.47	9%	60.3°
2027-12-31 Fri	51	—	unknown	18:45–21:00 (good, 2.25 h)	87.2° 14:40	11.46	15%	56.7°
2028-01-01 Sat	46	—	unknown	18:45–20:50 (good, 2.08 h)	87.2° 14:40	11.45	22%	54.6°
2028-01-02 Sun	40	—	unknown	18:45–20:40 (good, 1.92 h)	87.2° 14:35	11.44	30%	54.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-12-04&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.