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: 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100), 10-01 (100) — by astronomy; check the weather when the night is within four days.

2035-09-16astronomy score per night — click a bar for that night2035-10-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-09-16 Sun	61	—	unknown	03:00–05:30 (good, 2.5 h)	72.5° 05:25	8.42	100%	74.1°
2035-09-17 Mon	44	—	unknown	05:25–05:30 (good, 0.08 h)	72.5° 05:20	8.47	100%	61.2°
2035-09-18 Tue	30	—	unknown	00:20–05:35 (marginal, 5.25 h)	72.5° 05:20	8.52	98%	48.1°
2035-09-19 Wed	21	—	unknown	00:25–05:35 (marginal, 5.17 h)	72.5° 05:15	8.57	94%	35.0°
2035-09-20 Thu	21	—	unknown	00:10–05:35 (marginal, 5.42 h)	72.5° 05:10	8.62	87%	22.1°
2035-09-21 Fri	29	—	unknown	23:50–05:35 (marginal, 5.75 h)	72.5° 05:05	8.67	79%	11.2°
2035-09-22 Sat	42	—	unknown	23:35–05:40 (marginal, 6.08 h)	72.5° 05:05	8.73	69%	12.1°
2035-09-23 Sun	60	—	unknown	00:55–03:55 (good, 3.0 h)	72.5° 05:00	8.78	58%	23.7°
2035-09-24 Mon	81	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 04:55	8.83	46%	37.1°
2035-09-25 Tue	89	—	unknown	23:45–05:40 (good, 5.92 h)	72.5° 04:50	8.88	35%	50.9°
2035-09-26 Wed	97	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:45	8.93	25%	64.8°
2035-09-27 Thu	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:45	8.98	16%	78.7°
2035-09-28 Fri	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:40	9.02	8%	92.5°
2035-09-29 Sat	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.5° 04:35	9.07	3%	106.3°
2035-09-30 Sun	100	—	unknown	23:25–05:45 (good, 6.33 h)	72.5° 04:30	9.12	0%	119.8°
2035-10-01 Mon	100	—	unknown	23:20–05:50 (good, 6.5 h)	72.5° 04:25	9.17	0%	132.9°
2035-10-02 Tue	100	—	unknown	23:15–05:50 (good, 6.58 h)	72.5° 04:25	9.22	2%	145.7°
2035-10-03 Wed	100	—	unknown	23:15–05:50 (good, 6.58 h)	72.5° 04:20	9.27	6%	157.7°
2035-10-04 Thu	100	—	unknown	23:10–05:50 (good, 6.67 h)	72.5° 04:15	9.31	12%	167.9°
2035-10-05 Fri	100	—	unknown	23:05–05:55 (good, 6.83 h)	72.5° 04:10	9.36	19%	169.7°
2035-10-06 Sat	100	—	unknown	23:00–05:55 (good, 6.92 h)	72.5° 04:05	9.41	27%	161.1°
2035-10-07 Sun	100	—	unknown	23:00–05:55 (good, 6.92 h)	72.5° 04:05	9.45	36%	150.1°
2035-10-08 Mon	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 04:00	9.5	45%	138.8°
2035-10-09 Tue	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 03:55	9.55	55%	127.2°
2035-10-10 Wed	100	—	unknown	22:55–06:00 (good, 7.08 h)	72.5° 03:50	9.59	64%	115.5°
2035-10-11 Thu	100	—	unknown	22:55–06:00 (good, 7.08 h)	72.5° 03:50	9.64	73%	103.6°
2035-10-12 Fri	100	—	unknown	23:00–06:00 (good, 7.0 h)	72.5° 03:45	9.68	81%	91.4°
2035-10-13 Sat	100	—	unknown	00:05–06:00 (good, 5.92 h)	72.5° 03:40	9.73	89%	78.9°
2035-10-14 Sun	100	—	unknown	01:50–06:05 (good, 4.25 h)	72.5° 03:35	9.77	94%	66.1°
2035-10-15 Mon	64	—	unknown	04:55–06:05 (good, 1.17 h)	72.5° 03:30	9.81	98%	52.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-09-16&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.