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 Great Orion Nebula: 08-28 (5), 08-27 (4), 08-26 (3), 08-25 (2), 08-23 (1) — by astronomy; check the weather when the night is within four days.

2046-07-30astronomy score per night — click a bar for that night2046-08-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-07-30 Mon	0	—	unknown	—	42.9° 10:20	5.75	8%	33.3°
2046-07-31 Tue	0	—	unknown	—	42.9° 10:20	5.8	3%	39.0°
2046-08-01 Wed	0	—	unknown	—	42.9° 10:15	5.86	0%	47.9°
2046-08-02 Thu	0	—	unknown	—	42.9° 10:10	5.91	0%	58.8°
2046-08-03 Fri	0	—	unknown	—	42.9° 10:05	5.97	3%	70.8°
2046-08-04 Sat	0	—	unknown	—	42.9° 10:05	6.02	9%	83.2°
2046-08-05 Sun	0	—	unknown	—	42.9° 10:00	6.08	17%	95.7°
2046-08-06 Mon	0	—	unknown	—	42.9° 09:55	6.14	27%	107.9°
2046-08-07 Tue	0	—	unknown	—	42.9° 09:50	6.19	37%	119.6°
2046-08-08 Wed	0	—	unknown	—	42.9° 09:45	6.25	49%	130.2°
2046-08-09 Thu	0	—	unknown	—	42.9° 09:45	6.31	60%	139.2°
2046-08-10 Fri	0	—	unknown	—	42.9° 09:40	6.36	70%	145.6°
2046-08-11 Sat	0	—	unknown	—	42.9° 09:35	6.42	79%	147.9°
2046-08-12 Sun	0	—	unknown	—	42.9° 09:30	6.48	87%	145.7°
2046-08-13 Mon	0	—	unknown	—	42.9° 09:25	6.54	93%	139.9°
2046-08-14 Tue	0	—	unknown	—	42.9° 09:25	6.59	97%	131.9°
2046-08-15 Wed	0	—	unknown	—	42.9° 09:20	6.65	100%	122.7°
2046-08-16 Thu	0	—	unknown	—	42.9° 09:15	6.71	100%	113.0°
2046-08-17 Fri	0	—	unknown	—	42.9° 09:10	6.77	98%	103.1°
2046-08-18 Sat	0	—	unknown	—	42.9° 09:10	6.82	95%	93.0°
2046-08-19 Sun	0	—	unknown	—	42.9° 09:05	6.88	90%	83.0°
2046-08-20 Mon	0	—	unknown	—	42.9° 09:00	6.94	84%	73.1°
2046-08-21 Tue	0	—	unknown	—	42.9° 08:55	7.0	76%	63.3°
2046-08-22 Wed	0	—	unknown	—	42.9° 08:50	7.05	68%	54.0°
2046-08-23 Thu	1	—	unknown	—	42.9° 08:50	7.11	58%	45.4°
2046-08-24 Fri	1	—	unknown	—	42.9° 08:45	7.17	48%	38.0°
2046-08-25 Sat	2	—	unknown	04:55–05:05 (marginal, 0.17 h)	42.9° 08:40	7.23	38%	33.2°
2046-08-26 Sun	3	—	unknown	04:50–05:05 (marginal, 0.25 h)	42.9° 08:35	7.28	28%	32.3°
2046-08-27 Mon	4	—	unknown	04:45–05:05 (marginal, 0.33 h)	42.9° 08:30	7.34	19%	36.1°
2046-08-28 Tue	5	—	unknown	04:45–05:05 (marginal, 0.33 h)	42.9° 08:30	7.4	11%	43.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-07-30&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.