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: 10-16 (89), 10-17 (89), 10-18 (89), 10-19 (89), 10-20 (89) — by astronomy; check the weather when the night is within four days.

2045-10-15astronomy score per night — click a bar for that night2045-11-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-10-15 Sun	87	—	unknown	02:05–06:05 (good, 4.0 h)	42.9° 05:20	9.84	32%	146.4°
2045-10-16 Mon	89	—	unknown	02:00–06:05 (good, 4.08 h)	42.9° 05:15	9.88	42%	142.3°
2045-10-17 Tue	89	—	unknown	01:55–06:05 (good, 4.17 h)	42.9° 05:10	9.92	51%	135.6°
2045-10-18 Wed	89	—	unknown	01:55–06:10 (good, 4.25 h)	42.9° 05:05	9.97	61%	127.5°
2045-10-19 Thu	89	—	unknown	01:55–06:10 (good, 4.25 h)	42.9° 05:05	10.01	70%	118.5°
2045-10-20 Fri	89	—	unknown	01:55–06:10 (good, 4.25 h)	42.9° 05:00	10.05	78%	108.9°
2045-10-21 Sat	89	—	unknown	02:00–06:10 (good, 4.17 h)	42.9° 04:55	10.09	85%	99.1°
2045-10-22 Sun	82	—	unknown	02:20–06:10 (good, 3.83 h)	42.9° 04:50	10.13	91%	89.0°
2045-10-23 Mon	71	—	unknown	03:45–06:15 (good, 2.5 h)	42.9° 04:45	10.17	96%	78.7°
2045-10-24 Tue	41	—	unknown	01:25–06:15 (marginal, 4.83 h)	42.9° 04:45	10.21	99%	68.5°
2045-10-25 Wed	29	—	unknown	01:40–06:15 (marginal, 4.58 h)	42.9° 04:40	10.25	100%	58.4°
2045-10-26 Thu	20	—	unknown	02:20–06:15 (marginal, 3.92 h)	42.9° 04:35	10.29	99%	48.9°
2045-10-27 Fri	15	—	unknown	04:10–06:15 (marginal, 2.08 h)	42.9° 04:30	10.33	95%	40.6°
2045-10-28 Sat	13	—	unknown	04:20–05:20 (marginal, 1.0 h)	42.9° 03:25	10.37	90%	34.7°
2045-10-29 Sun	16	—	unknown	00:25–05:20 (marginal, 4.92 h)	42.9° 03:25	10.41	82%	32.8°
2045-10-30 Mon	27	—	unknown	23:55–05:20 (marginal, 5.42 h)	42.9° 03:20	10.44	73%	35.8°
2045-10-31 Tue	42	—	unknown	23:35–05:20 (marginal, 5.75 h)	42.9° 03:15	10.48	63%	42.7°
2045-11-01 Wed	62	—	unknown	00:25–04:35 (good, 4.17 h)	42.9° 03:10	10.52	52%	52.0°
2045-11-02 Thu	77	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 03:10	10.55	41%	62.8°
2045-11-03 Fri	86	—	unknown	23:50–05:25 (good, 5.58 h)	42.9° 03:05	10.59	30%	74.4°
2045-11-04 Sat	89	—	unknown	23:45–05:25 (good, 5.67 h)	42.9° 03:00	10.62	20%	86.3°
2045-11-05 Sun	89	—	unknown	23:40–05:25 (good, 5.75 h)	42.9° 02:55	10.66	11%	98.3°
2045-11-06 Mon	89	—	unknown	23:40–05:30 (good, 5.83 h)	42.9° 02:50	10.69	5%	110.2°
2045-11-07 Tue	89	—	unknown	23:35–05:30 (good, 5.92 h)	42.9° 02:50	10.72	1%	121.5°
2045-11-08 Wed	89	—	unknown	23:30–05:30 (good, 6.0 h)	42.9° 02:45	10.76	0%	131.7°
2045-11-09 Thu	89	—	unknown	23:25–05:30 (good, 6.08 h)	42.9° 02:40	10.79	1%	140.2°
2045-11-10 Fri	89	—	unknown	23:20–05:30 (good, 6.17 h)	42.9° 02:35	10.82	5%	145.8°
2045-11-11 Sat	89	—	unknown	23:20–05:35 (good, 6.25 h)	42.9° 02:30	10.85	10%	147.2°
2045-11-12 Sun	89	—	unknown	23:15–05:35 (good, 6.33 h)	42.9° 02:30	10.88	17%	144.4°
2045-11-13 Mon	89	—	unknown	23:10–05:35 (good, 6.42 h)	42.9° 02:25	10.91	25%	138.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-10-15&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.