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 Seven Sisters: 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100), 09-27 (100) — by astronomy; check the weather when the night is within four days.

2042-09-23astronomy score per night — click a bar for that night2042-10-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-09-23 Tue	100	—	unknown	23:55–05:40 (good, 5.75 h)	72.5° 05:00	8.79	64%	132.6°
2042-09-24 Wed	100	—	unknown	23:55–05:40 (good, 5.75 h)	72.5° 04:55	8.84	74%	119.2°
2042-09-25 Thu	100	—	unknown	00:00–05:40 (good, 5.67 h)	72.6° 04:50	8.89	83%	105.4°
2042-09-26 Fri	100	—	unknown	00:05–05:45 (good, 5.67 h)	72.5° 04:45	8.94	91%	91.2°
2042-09-27 Sat	100	—	unknown	01:45–05:45 (good, 4.0 h)	72.5° 04:40	8.99	96%	76.5°
2042-09-28 Sun	58	—	unknown	04:40–05:45 (good, 1.08 h)	72.5° 04:40	9.04	100%	61.4°
2042-09-29 Mon	35	—	unknown	23:45–05:45 (marginal, 6.0 h)	72.6° 04:35	9.09	100%	46.2°
2042-09-30 Tue	20	—	unknown	03:55–05:50 (marginal, 1.92 h)	72.6° 04:30	9.14	97%	31.0°
2042-10-01 Wed	19	—	unknown	23:35–05:50 (marginal, 6.25 h)	72.5° 04:25	9.19	91%	15.9°
2042-10-02 Thu	27	—	unknown	23:10–05:50 (marginal, 6.67 h)	72.5° 04:20	9.23	83%	1.3°
2042-10-03 Fri	40	—	unknown	22:55–05:50 (marginal, 6.92 h)	72.5° 04:20	9.28	73%	13.2°
2042-10-04 Sat	59	—	unknown	22:40–05:50 (marginal, 7.17 h)	72.6° 04:15	9.33	63%	27.2°
2042-10-05 Sun	72	—	unknown	23:25–05:55 (good, 6.5 h)	72.6° 04:10	9.38	52%	40.7°
2042-10-06 Mon	87	—	unknown	23:00–05:55 (good, 6.92 h)	72.5° 04:05	9.42	41%	53.7°
2042-10-07 Tue	96	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 04:05	9.47	32%	66.5°
2042-10-08 Wed	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 04:00	9.51	23%	79.0°
2042-10-09 Thu	100	—	unknown	22:50–06:00 (good, 7.17 h)	72.6° 03:55	9.56	15%	91.2°
2042-10-10 Fri	100	—	unknown	22:45–06:00 (good, 7.25 h)	72.5° 03:50	9.61	9%	103.3°
2042-10-11 Sat	100	—	unknown	22:40–06:00 (good, 7.33 h)	72.5° 03:45	9.65	4%	115.3°
2042-10-12 Sun	100	—	unknown	22:35–06:00 (good, 7.42 h)	72.5° 03:45	9.69	1%	127.2°
2042-10-13 Mon	100	—	unknown	22:35–06:00 (good, 7.42 h)	72.6° 03:40	9.74	0%	139.0°
2042-10-14 Tue	100	—	unknown	22:30–06:05 (good, 7.58 h)	72.6° 03:35	9.78	1%	150.8°
2042-10-15 Wed	100	—	unknown	22:25–06:05 (good, 7.67 h)	72.5° 03:30	9.83	3%	162.7°
2042-10-16 Thu	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.5° 03:25	9.87	7%	174.5°
2042-10-17 Fri	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.5° 03:25	9.91	13%	173.4°
2042-10-18 Sat	100	—	unknown	22:15–06:05 (good, 7.83 h)	72.6° 03:20	9.95	20%	161.4°
2042-10-19 Sun	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.6° 03:15	10.0	28%	149.1°
2042-10-20 Mon	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.5° 03:10	10.04	38%	136.6°
2042-10-21 Tue	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:10	10.08	48%	123.7°
2042-10-22 Wed	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:05	10.12	58%	110.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-09-23&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.