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: 10-26 (89), 10-27 (89), 10-28 (89), 10-29 (89), 10-30 (89) — by astronomy; check the weather when the night is within four days.

2046-10-18astronomy score per night — click a bar for that night2046-11-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-10-18 Thu	13	—	unknown	02:25–06:10 (marginal, 3.75 h)	42.9° 05:10	9.96	86%	35.0°
2046-10-19 Fri	15	—	unknown	02:00–06:10 (marginal, 4.17 h)	42.9° 05:05	10.0	78%	31.8°
2046-10-20 Sat	23	—	unknown	01:35–06:10 (marginal, 4.58 h)	42.9° 05:00	10.04	70%	32.8°
2046-10-21 Sun	36	—	unknown	01:15–06:10 (marginal, 4.92 h)	42.9° 04:55	10.08	60%	37.9°
2046-10-22 Mon	51	—	unknown	02:05–06:00 (good, 3.92 h)	42.9° 04:50	10.12	49%	46.0°
2046-10-23 Tue	68	—	unknown	01:50–06:15 (good, 4.42 h)	42.9° 04:50	10.16	38%	56.0°
2046-10-24 Wed	83	—	unknown	01:30–06:15 (good, 4.75 h)	42.9° 04:45	10.2	28%	67.3°
2046-10-25 Thu	88	—	unknown	01:25–06:15 (good, 4.83 h)	42.9° 04:40	10.24	18%	79.4°
2046-10-26 Fri	89	—	unknown	01:20–06:15 (good, 4.92 h)	42.9° 04:35	10.28	10%	92.0°
2046-10-27 Sat	89	—	unknown	01:20–05:15 (good, 4.92 h)	42.9° 03:30	10.32	4%	104.7°
2046-10-28 Sun	89	—	unknown	00:15–05:20 (good, 5.08 h)	42.9° 03:30	10.36	1%	117.2°
2046-10-29 Mon	89	—	unknown	00:10–05:20 (good, 5.17 h)	42.9° 03:25	10.4	0%	129.0°
2046-10-30 Tue	89	—	unknown	00:05–05:20 (good, 5.25 h)	42.9° 03:20	10.43	3%	139.0°
2046-10-31 Wed	89	—	unknown	00:00–05:20 (good, 5.33 h)	42.9° 03:15	10.47	8%	146.1°
2046-11-01 Thu	89	—	unknown	00:00–05:25 (good, 5.42 h)	42.9° 03:15	10.51	16%	148.5°
2046-11-02 Fri	89	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 03:10	10.54	25%	145.6°
2046-11-03 Sat	89	—	unknown	23:50–05:25 (good, 5.58 h)	42.9° 03:05	10.58	34%	139.0°
2046-11-04 Sun	89	—	unknown	23:45–05:25 (good, 5.67 h)	42.9° 03:00	10.61	44%	130.5°
2046-11-05 Mon	89	—	unknown	23:45–05:25 (good, 5.67 h)	42.9° 02:55	10.65	54%	121.0°
2046-11-06 Tue	89	—	unknown	23:50–05:30 (good, 5.67 h)	42.9° 02:55	10.68	63%	111.2°
2046-11-07 Wed	89	—	unknown	23:50–05:30 (good, 5.67 h)	42.9° 02:50	10.72	72%	101.2°
2046-11-08 Thu	89	—	unknown	00:00–05:30 (good, 5.5 h)	42.9° 02:45	10.75	80%	91.1°
2046-11-09 Fri	87	—	unknown	00:55–05:30 (good, 4.58 h)	42.9° 02:40	10.78	87%	81.0°
2046-11-10 Sat	82	—	unknown	02:45–05:30 (good, 2.75 h)	42.9° 02:35	10.81	93%	71.1°
2046-11-11 Sun	45	—	unknown	23:25–05:35 (marginal, 6.17 h)	42.9° 02:35	10.84	97%	61.3°
2046-11-12 Mon	31	—	unknown	23:45–05:35 (marginal, 5.83 h)	42.9° 02:30	10.87	99%	51.9°
2046-11-13 Tue	21	—	unknown	02:00–05:35 (marginal, 3.58 h)	42.9° 02:25	10.91	100%	43.3°
2046-11-14 Wed	14	—	unknown	04:25–05:15 (marginal, 0.83 h)	42.9° 02:20	10.93	98%	36.3°
2046-11-15 Thu	12	—	unknown	—	42.9° 02:20	10.96	95%	32.0°
2046-11-16 Fri	15	—	unknown	23:25–00:10 (marginal, 0.75 h)	42.9° 02:15	10.99	90%	31.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-10-18&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.