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: 11-16 (100), 11-17 (100), 11-18 (100), 11-19 (100), 11-20 (100) — by astronomy; check the weather when the night is within four days.

2027-11-09astronomy score per night — click a bar for that night2027-12-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-11-09 Tue	49	—	unknown	18:45–00:50 (marginal, 6.08 h)	87.2° 18:05	10.77	82%	55.3°
2027-11-10 Wed	44	—	unknown	18:45–00:35 (marginal, 5.83 h)	87.2° 18:00	10.8	89%	57.9°
2027-11-11 Thu	43	—	unknown	18:45–00:25 (marginal, 5.67 h)	87.2° 18:00	10.83	94%	62.2°
2027-11-12 Fri	47	—	unknown	18:40–18:50 (good, 0.17 h)	87.3° 17:55	10.86	98%	67.9°
2027-11-13 Sat	54	—	unknown	18:40–20:15 (good, 1.58 h)	87.3° 17:50	10.89	100%	74.7°
2027-11-14 Sun	66	—	unknown	18:40–21:25 (good, 2.75 h)	87.2° 17:45	10.92	99%	82.3°
2027-11-15 Mon	80	—	unknown	18:40–22:25 (good, 3.75 h)	87.2° 17:45	10.95	96%	90.4°
2027-11-16 Tue	100	—	unknown	18:40–23:25 (good, 4.75 h)	87.2° 17:40	10.98	90%	98.5°
2027-11-17 Wed	100	—	unknown	18:40–23:35 (good, 4.92 h)	87.3° 17:35	11.01	83%	106.4°
2027-11-18 Thu	100	—	unknown	18:40–23:40 (good, 5.0 h)	87.2° 17:30	11.04	73%	113.5°
2027-11-19 Fri	100	—	unknown	18:35–23:40 (good, 5.08 h)	87.2° 17:25	11.06	63%	119.4°
2027-11-20 Sat	100	—	unknown	18:35–23:45 (good, 5.17 h)	87.2° 17:25	11.09	51%	123.5°
2027-11-21 Sun	100	—	unknown	18:35–23:40 (good, 5.08 h)	87.2° 17:20	11.11	40%	125.5°
2027-11-22 Mon	100	—	unknown	18:35–23:35 (good, 5.0 h)	87.3° 17:15	11.14	29%	125.0°
2027-11-23 Tue	100	—	unknown	18:35–23:30 (good, 4.92 h)	87.2° 17:10	11.16	20%	122.3°
2027-11-24 Wed	100	—	unknown	18:35–23:25 (good, 4.83 h)	87.2° 17:05	11.19	12%	117.6°
2027-11-25 Thu	100	—	unknown	18:35–23:25 (good, 4.83 h)	87.2° 17:05	11.21	6%	111.6°
2027-11-26 Fri	100	—	unknown	18:35–23:20 (good, 4.75 h)	87.3° 17:00	11.23	2%	104.7°
2027-11-27 Sat	100	—	unknown	18:35–23:15 (good, 4.67 h)	87.3° 16:55	11.25	0%	97.3°
2027-11-28 Sun	100	—	unknown	18:35–23:10 (good, 4.58 h)	87.2° 16:50	11.27	1%	89.9°
2027-11-29 Mon	100	—	unknown	18:35–23:10 (good, 4.58 h)	87.2° 16:50	11.29	3%	82.5°
2027-11-30 Tue	100	—	unknown	18:35–23:05 (good, 4.5 h)	87.2° 16:45	11.31	8%	75.6°
2027-12-01 Wed	99	—	unknown	18:35–23:00 (good, 4.42 h)	87.3° 16:40	11.33	14%	69.2°
2027-12-02 Thu	93	—	unknown	18:35–22:55 (good, 4.33 h)	87.2° 16:35	11.34	21%	63.7°
2027-12-03 Fri	88	—	unknown	18:35–22:50 (good, 4.25 h)	87.2° 16:30	11.36	29%	59.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-11-09&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.