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: 09-09 (100), 09-10 (100), 09-11 (100), 09-12 (100), 09-13 (100) — by astronomy; check the weather when the night is within four days.

2034-08-17astronomy score per night — click a bar for that night2034-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-08-17 Thu	67	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:25	6.76	15%	129.9°
2034-08-18 Fri	69	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.82	22%	141.8°
2034-08-19 Sat	72	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:15	6.88	31%	153.3°
2034-08-20 Sun	74	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:10	6.93	40%	164.0°
2034-08-21 Mon	77	—	unknown	02:00–04:55 (good, 2.92 h)	72.5° 07:05	6.99	49%	171.0°
2034-08-22 Tue	80	—	unknown	02:00–05:00 (good, 3.0 h)	72.5° 07:05	7.05	58%	166.4°
2034-08-23 Wed	82	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:00	7.11	68%	156.1°
2034-08-24 Thu	85	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 06:55	7.16	77%	144.5°
2034-08-25 Fri	84	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 06:50	7.22	84%	132.4°
2034-08-26 Sat	85	—	unknown	01:50–05:05 (good, 3.25 h)	72.5° 06:50	7.28	91%	119.9°
2034-08-27 Sun	69	—	unknown	01:55–05:05 (good, 3.17 h)	72.5° 06:45	7.33	96%	107.0°
2034-08-28 Mon	57	—	unknown	02:15–05:05 (good, 2.83 h)	72.5° 06:40	7.39	99%	93.7°
2034-08-29 Tue	44	—	unknown	03:35–05:10 (good, 1.58 h)	72.5° 06:35	7.45	100%	80.1°
2034-08-30 Wed	32	—	unknown	01:20–05:10 (marginal, 3.83 h)	72.5° 06:30	7.5	98%	66.2°
2034-08-31 Thu	24	—	unknown	01:25–05:10 (marginal, 3.75 h)	72.5° 06:30	7.56	94%	52.2°
2034-09-01 Fri	19	—	unknown	01:20–05:10 (marginal, 3.83 h)	72.5° 06:25	7.61	87%	38.2°
2034-09-02 Sat	20	—	unknown	01:10–05:15 (marginal, 4.08 h)	72.5° 06:20	7.67	78%	24.5°
2034-09-03 Sun	29	—	unknown	00:55–05:15 (marginal, 4.33 h)	72.5° 06:15	7.73	68%	12.4°
2034-09-04 Mon	42	—	unknown	03:50–04:35 (good, 0.75 h)	72.5° 06:10	7.78	56%	10.5°
2034-09-05 Tue	57	—	unknown	01:25–05:15 (good, 3.83 h)	72.5° 06:10	7.84	45%	21.6°
2034-09-06 Wed	78	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:05	7.89	34%	34.8°
2034-09-07 Thu	90	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:00	7.95	24%	48.2°
2034-09-08 Fri	96	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 05:55	8.0	15%	61.6°
2034-09-09 Sat	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:55	8.05	8%	74.8°
2034-09-10 Sun	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:50	8.11	3%	87.9°
2034-09-11 Mon	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.5° 05:45	8.16	1%	100.7°
2034-09-12 Tue	100	—	unknown	00:35–05:25 (good, 4.83 h)	72.5° 05:40	8.22	0%	113.4°
2034-09-13 Wed	100	—	unknown	00:30–05:30 (good, 5.0 h)	72.5° 05:35	8.27	2%	125.7°
2034-09-14 Thu	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:35	8.32	5%	137.8°
2034-09-15 Fri	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:30	8.38	10%	149.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-08-17&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.