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: 09-19 (100), 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100) — by astronomy; check the weather when the night is within four days.

2033-09-11astronomy score per night — click a bar for that night2033-10-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-09-11 Sun	17	—	unknown	00:50–05:25 (marginal, 4.58 h)	72.5° 05:45	8.18	88%	31.0°
2033-09-12 Mon	23	—	unknown	00:30–05:25 (marginal, 4.92 h)	72.5° 05:40	8.23	80%	17.2°
2033-09-13 Tue	34	—	unknown	00:10–05:30 (marginal, 5.33 h)	72.5° 05:35	8.28	70%	8.0°
2033-09-14 Wed	49	—	unknown	03:30–03:40 (good, 0.17 h)	72.5° 05:30	8.34	59%	15.2°
2033-09-15 Thu	68	—	unknown	00:45–05:30 (good, 4.75 h)	72.5° 05:30	8.39	48%	27.6°
2033-09-16 Fri	83	—	unknown	00:20–05:30 (good, 5.17 h)	72.5° 05:25	8.44	37%	40.4°
2033-09-17 Sat	91	—	unknown	00:15–05:35 (good, 5.33 h)	72.5° 05:20	8.49	28%	53.0°
2033-09-18 Sun	98	—	unknown	00:10–05:35 (good, 5.42 h)	72.5° 05:15	8.54	19%	65.4°
2033-09-19 Mon	100	—	unknown	00:05–05:35 (good, 5.5 h)	72.5° 05:10	8.6	12%	77.7°
2033-09-20 Tue	100	—	unknown	00:05–05:35 (good, 5.5 h)	72.5° 05:10	8.65	6%	89.8°
2033-09-21 Wed	100	—	unknown	00:00–05:40 (good, 5.67 h)	72.5° 05:05	8.7	2%	101.7°
2033-09-22 Thu	100	—	unknown	23:55–05:40 (good, 5.75 h)	72.5° 05:00	8.75	0%	113.5°
2033-09-23 Fri	100	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 04:55	8.8	0%	125.3°
2033-09-24 Sat	100	—	unknown	23:45–05:40 (good, 5.92 h)	72.5° 04:55	8.85	2%	136.9°
2033-09-25 Sun	100	—	unknown	23:45–05:40 (good, 5.92 h)	72.5° 04:50	8.9	5%	148.4°
2033-09-26 Mon	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:45	8.95	10%	159.6°
2033-09-27 Tue	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:40	9.0	16%	169.4°
2033-09-28 Wed	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.5° 04:35	9.05	24%	170.5°
2033-09-29 Thu	100	—	unknown	23:25–05:45 (good, 6.33 h)	72.5° 04:35	9.1	32%	161.0°
2033-09-30 Fri	100	—	unknown	23:25–05:50 (good, 6.42 h)	72.5° 04:30	9.15	42%	149.3°
2033-10-01 Sat	100	—	unknown	23:25–05:50 (good, 6.42 h)	72.5° 04:25	9.19	52%	136.9°
2033-10-02 Sun	100	—	unknown	23:20–05:50 (good, 6.5 h)	72.5° 04:20	9.24	63%	124.0°
2033-10-03 Mon	100	—	unknown	23:20–05:50 (good, 6.5 h)	72.5° 04:15	9.29	73%	110.6°
2033-10-04 Tue	100	—	unknown	23:30–05:50 (good, 6.33 h)	72.5° 04:15	9.34	83%	96.6°
2033-10-05 Wed	100	—	unknown	00:25–05:55 (good, 5.5 h)	72.5° 04:10	9.38	91%	82.3°
2033-10-06 Thu	100	—	unknown	02:25–05:55 (good, 3.5 h)	72.5° 04:05	9.43	96%	67.5°
2033-10-07 Fri	54	—	unknown	05:45–05:55 (good, 0.17 h)	72.5° 04:00	9.48	100%	52.5°
2033-10-08 Sat	31	—	unknown	01:00–05:55 (marginal, 4.92 h)	72.5° 04:00	9.52	100%	37.5°
2033-10-09 Sun	22	—	unknown	04:10–06:00 (marginal, 1.83 h)	72.5° 03:55	9.57	97%	22.9°
2033-10-10 Mon	25	—	unknown	22:45–06:00 (marginal, 7.25 h)	72.5° 03:50	9.61	91%	10.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-09-11&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.