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: 01-11 (36), 01-12 (34), 01-13 (33), 01-14 (32), 01-15 (30) — by astronomy; check the weather when the night is within four days.

2037-01-11astronomy score per night — click a bar for that night2037-02-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-01-11 Sun	36	—	unknown	18:55–20:15 (good, 1.33 h)	87.2° 13:55	11.3	19%	90.4°
2037-01-12 Mon	34	—	unknown	18:55–20:10 (good, 1.25 h)	87.2° 13:50	11.28	11%	84.0°
2037-01-13 Tue	33	—	unknown	18:55–20:10 (good, 1.25 h)	87.2° 13:50	11.26	6%	78.0°
2037-01-14 Wed	32	—	unknown	18:55–20:05 (good, 1.17 h)	87.2° 13:45	11.24	2%	72.5°
2037-01-15 Thu	30	—	unknown	18:55–20:00 (good, 1.08 h)	87.2° 13:40	11.22	0%	67.7°
2037-01-16 Fri	29	—	unknown	18:55–19:55 (good, 1.0 h)	87.2° 13:35	11.2	0%	63.9°
2037-01-17 Sat	26	—	unknown	19:00–19:50 (good, 0.83 h)	87.2° 13:30	11.17	2%	61.3°
2037-01-18 Sun	25	—	unknown	19:00–19:50 (good, 0.83 h)	87.2° 13:30	11.15	6%	60.1°
2037-01-19 Mon	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.2° 13:25	11.12	11%	60.2°
2037-01-20 Tue	20	—	unknown	19:00–19:35 (good, 0.58 h)	87.2° 13:20	11.1	17%	61.7°
2037-01-21 Wed	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.2° 13:15	11.07	25%	64.5°
2037-01-22 Thu	15	—	unknown	19:05–19:15 (good, 0.17 h)	87.2° 13:15	11.05	34%	68.4°
2037-01-23 Fri	13	—	unknown	18:30–20:05 (marginal, 1.58 h)	87.2° 13:10	11.02	43%	73.2°
2037-01-24 Sat	11	—	unknown	19:05–20:00 (marginal, 0.92 h)	87.2° 13:05	10.99	53%	78.8°
2037-01-25 Sun	10	—	unknown	19:05–19:55 (marginal, 0.83 h)	87.2° 13:00	10.96	63%	85.0°
2037-01-26 Mon	8	—	unknown	19:10–19:50 (marginal, 0.67 h)	87.2° 12:55	10.93	73%	91.6°
2037-01-27 Tue	8	—	unknown	19:10–19:50 (marginal, 0.67 h)	87.2° 12:55	10.9	82%	98.3°
2037-01-28 Wed	8	—	unknown	19:10–19:45 (marginal, 0.58 h)	87.2° 12:50	10.87	90%	104.9°
2037-01-29 Thu	8	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.84	96%	110.9°
2037-01-30 Fri	8	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.2° 12:40	10.81	99%	115.8°
2037-01-31 Sat	7	—	unknown	19:15–19:30 (marginal, 0.25 h)	87.2° 12:35	10.78	100%	119.0°
2037-02-01 Sun	7	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.2° 12:35	10.75	97%	120.0°
2037-02-02 Mon	7	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:30	10.71	92%	118.8°
2037-02-03 Tue	8	—	unknown	05:30–06:00 (marginal, 0.5 h)	87.2° 12:25	10.68	84%	115.4°
2037-02-04 Wed	7	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.64	74%	110.6°
2037-02-05 Thu	7	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.61	64%	104.7°
2037-02-06 Fri	8	—	unknown	05:20–05:55 (marginal, 0.58 h)	87.2° 12:15	10.57	53%	98.4°
2037-02-07 Sat	9	—	unknown	05:15–05:55 (marginal, 0.67 h)	87.2° 12:10	10.54	43%	91.9°
2037-02-08 Sun	9	—	unknown	05:10–05:50 (marginal, 0.67 h)	87.2° 12:05	10.5	33%	85.4°
2037-02-09 Mon	9	—	unknown	05:10–06:25 (marginal, 1.25 h)	87.2° 12:00	10.46	24%	79.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-01-11&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.