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), 10-25 (88), 10-24 (83), 10-09 (76) — by astronomy; check the weather when the night is within four days.

2046-09-28astronomy score per night — click a bar for that night2046-10-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-09-28 Fri	59	—	unknown	03:10–05:45 (good, 2.58 h)	42.9° 06:25	9.04	2%	84.8°
2046-09-29 Sat	60	—	unknown	03:10–05:45 (good, 2.58 h)	42.9° 06:20	9.09	0%	97.8°
2046-09-30 Sun	62	—	unknown	03:05–05:50 (good, 2.75 h)	42.9° 06:20	9.14	1%	110.6°
2046-10-01 Mon	63	—	unknown	03:00–05:50 (good, 2.83 h)	42.9° 06:15	9.19	5%	122.8°
2046-10-02 Tue	66	—	unknown	02:55–05:50 (good, 2.92 h)	42.9° 06:10	9.24	12%	133.7°
2046-10-03 Wed	67	—	unknown	02:55–05:50 (good, 2.92 h)	42.9° 06:05	9.28	20%	142.4°
2046-10-04 Thu	68	—	unknown	02:50–05:50 (good, 3.0 h)	42.9° 06:05	9.33	30%	147.5°
2046-10-05 Fri	70	—	unknown	02:45–05:55 (good, 3.17 h)	42.9° 06:00	9.38	40%	147.7°
2046-10-06 Sat	72	—	unknown	02:40–05:55 (good, 3.25 h)	42.9° 05:55	9.42	51%	143.4°
2046-10-07 Sun	74	—	unknown	02:35–05:55 (good, 3.33 h)	42.9° 05:50	9.47	61%	136.3°
2046-10-08 Mon	75	—	unknown	02:35–05:55 (good, 3.33 h)	42.9° 05:45	9.52	70%	127.6°
2046-10-09 Tue	76	—	unknown	02:35–06:00 (good, 3.42 h)	42.9° 05:45	9.56	78%	118.1°
2046-10-10 Wed	75	—	unknown	02:40–06:00 (good, 3.33 h)	42.9° 05:40	9.61	86%	108.3°
2046-10-11 Thu	70	—	unknown	02:45–06:00 (good, 3.25 h)	42.9° 05:35	9.65	92%	98.3°
2046-10-12 Fri	64	—	unknown	03:20–06:00 (good, 2.67 h)	42.9° 05:30	9.7	96%	88.3°
2046-10-13 Sat	41	—	unknown	04:45–06:00 (good, 1.25 h)	42.9° 05:25	9.74	99%	78.2°
2046-10-14 Sun	31	—	unknown	02:05–06:05 (marginal, 4.0 h)	42.9° 05:25	9.78	100%	68.3°
2046-10-15 Mon	23	—	unknown	02:20–06:05 (marginal, 3.75 h)	42.9° 05:20	9.83	99%	58.7°
2046-10-16 Tue	17	—	unknown	02:30–06:05 (marginal, 3.58 h)	42.9° 05:15	9.87	96%	49.6°
2046-10-17 Wed	14	—	unknown	03:30–06:05 (marginal, 2.58 h)	42.9° 05:10	9.91	92%	41.4°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-09-28&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.