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), 10-15 (87), 10-16 (87), 11-01 (87) — by astronomy; check the weather when the night is within four days.

2029-10-05astronomy score per night — click a bar for that night2029-11-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-10-05 Fri	71	—	unknown	02:45–05:55 (good, 3.17 h)	42.9° 06:00	9.38	5%	82.0°
2029-10-06 Sat	72	—	unknown	02:40–05:55 (good, 3.25 h)	42.9° 05:55	9.43	1%	95.0°
2029-10-07 Sun	74	—	unknown	02:35–05:55 (good, 3.33 h)	42.9° 05:50	9.48	0%	108.1°
2029-10-08 Mon	75	—	unknown	02:30–05:55 (good, 3.42 h)	42.9° 05:45	9.52	2%	120.9°
2029-10-09 Tue	78	—	unknown	02:30–06:00 (good, 3.5 h)	42.9° 05:40	9.57	7%	132.9°
2029-10-10 Wed	79	—	unknown	02:25–06:00 (good, 3.58 h)	42.9° 05:40	9.61	14%	143.0°
2029-10-11 Thu	80	—	unknown	02:20–06:00 (good, 3.67 h)	42.9° 05:35	9.66	23%	149.6°
2029-10-12 Fri	82	—	unknown	02:15–06:00 (good, 3.75 h)	42.9° 05:30	9.7	33%	150.6°
2029-10-13 Sat	83	—	unknown	02:10–06:00 (good, 3.83 h)	42.9° 05:25	9.75	44%	146.1°
2029-10-14 Sun	86	—	unknown	02:10–06:05 (good, 3.92 h)	42.9° 05:20	9.79	55%	138.1°
2029-10-15 Mon	87	—	unknown	02:05–06:05 (good, 4.0 h)	42.9° 05:20	9.83	65%	128.5°
2029-10-16 Tue	87	—	unknown	02:05–06:05 (good, 4.0 h)	42.9° 05:15	9.88	74%	118.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-10-05&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.