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: 11-02 (89), 11-03 (89), 11-04 (89), 11-05 (89), 11-06 (89) — by astronomy; check the weather when the night is within four days.

2029-10-17astronomy score per night — click a bar for that night2029-11-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-10-17 Wed	86	—	unknown	02:10–06:05 (good, 3.92 h)	42.9° 05:10	9.92	82%	107.7°
2029-10-18 Thu	82	—	unknown	02:20–06:10 (good, 3.83 h)	42.9° 05:05	9.96	89%	97.1°
2029-10-19 Fri	74	—	unknown	03:00–06:10 (good, 3.17 h)	42.9° 05:00	10.0	94%	86.6°
2029-10-20 Sat	46	—	unknown	04:35–06:10 (good, 1.58 h)	42.9° 05:00	10.05	98%	76.1°
2029-10-21 Sun	35	—	unknown	01:40–06:10 (marginal, 4.5 h)	42.9° 04:55	10.09	100%	65.9°
2029-10-22 Mon	25	—	unknown	01:55–06:10 (marginal, 4.25 h)	42.9° 04:50	10.13	100%	56.1°
2029-10-23 Tue	18	—	unknown	02:45–06:15 (marginal, 3.5 h)	42.9° 04:45	10.17	98%	46.8°
2029-10-24 Wed	14	—	unknown	04:25–06:15 (marginal, 1.83 h)	42.9° 04:45	10.21	94%	38.5°
2029-10-25 Thu	12	—	unknown	05:35–06:15 (marginal, 0.67 h)	42.9° 04:40	10.25	89%	32.2°
2029-10-26 Fri	15	—	unknown	01:40–06:15 (marginal, 4.58 h)	42.9° 04:35	10.29	83%	29.0°
2029-10-27 Sat	22	—	unknown	01:10–05:15 (marginal, 5.08 h)	42.9° 03:30	10.32	75%	30.2°
2029-10-28 Sun	34	—	unknown	23:50–05:20 (marginal, 5.5 h)	42.9° 03:25	10.36	66%	35.6°
2029-10-29 Mon	50	—	unknown	01:35–02:05 (good, 0.5 h)	42.9° 03:25	10.4	56%	43.7°
2029-10-30 Tue	69	—	unknown	00:25–05:20 (good, 4.92 h)	42.9° 03:20	10.44	45%	53.6°
2029-10-31 Wed	83	—	unknown	00:00–05:20 (good, 5.33 h)	42.9° 03:15	10.48	35%	64.7°
2029-11-01 Thu	87	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 03:10	10.51	25%	76.6°
2029-11-02 Fri	89	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 03:05	10.55	15%	89.1°
2029-11-03 Sat	89	—	unknown	23:50–05:25 (good, 5.58 h)	42.9° 03:05	10.58	8%	102.0°
2029-11-04 Sun	89	—	unknown	23:45–05:25 (good, 5.67 h)	42.9° 03:00	10.62	3%	114.9°
2029-11-05 Mon	89	—	unknown	23:40–05:25 (good, 5.75 h)	42.9° 02:55	10.65	0%	127.5°
2029-11-06 Tue	89	—	unknown	23:40–05:30 (good, 5.83 h)	42.9° 02:50	10.69	1%	138.9°
2029-11-07 Wed	89	—	unknown	23:35–05:30 (good, 5.92 h)	42.9° 02:50	10.72	4%	147.5°
2029-11-08 Thu	89	—	unknown	23:30–05:30 (good, 6.0 h)	42.9° 02:45	10.75	11%	151.1°
2029-11-09 Fri	89	—	unknown	23:25–05:30 (good, 6.08 h)	42.9° 02:40	10.79	19%	148.4°
2029-11-10 Sat	89	—	unknown	23:20–05:30 (good, 6.17 h)	42.9° 02:35	10.82	28%	141.0°
2029-11-11 Sun	89	—	unknown	23:20–05:35 (good, 6.25 h)	42.9° 02:30	10.85	39%	131.5°
2029-11-12 Mon	89	—	unknown	23:20–05:35 (good, 6.25 h)	42.9° 02:30	10.88	49%	121.1°
2029-11-13 Tue	89	—	unknown	23:20–05:35 (good, 6.25 h)	42.9° 02:25	10.91	59%	110.5°
2029-11-14 Wed	89	—	unknown	23:25–05:35 (good, 6.17 h)	42.9° 02:20	10.94	68%	99.8°
2029-11-15 Thu	88	—	unknown	23:30–05:35 (good, 6.08 h)	42.9° 02:15	10.97	77%	89.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-10-17&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.