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: 09-07 (100), 09-08 (100), 09-09 (100), 09-10 (100), 09-11 (100) — by astronomy; check the weather when the night is within four days.

2037-08-21astronomy score per night — click a bar for that night2037-09-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-08-21 Fri	75	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:05	7.01	86%	133.5°
2037-08-22 Sat	76	—	unknown	02:05–05:00 (good, 2.92 h)	72.5° 07:00	7.06	92%	121.3°
2037-08-23 Sun	64	—	unknown	02:10–05:00 (good, 2.83 h)	72.5° 07:00	7.12	97%	109.3°
2037-08-24 Mon	55	—	unknown	02:15–05:00 (good, 2.75 h)	72.5° 06:55	7.18	99%	97.3°
2037-08-25 Tue	46	—	unknown	03:05–05:05 (good, 2.0 h)	72.5° 06:50	7.24	100%	85.5°
2037-08-26 Wed	36	—	unknown	04:15–05:05 (good, 0.83 h)	72.5° 06:45	7.29	99%	73.7°
2037-08-27 Thu	28	—	unknown	01:30–05:05 (marginal, 3.58 h)	72.5° 06:45	7.35	96%	62.0°
2037-08-28 Fri	23	—	unknown	01:30–05:05 (marginal, 3.58 h)	72.5° 06:40	7.41	91%	50.4°
2037-08-29 Sat	20	—	unknown	01:30–05:10 (marginal, 3.67 h)	72.5° 06:35	7.46	85%	38.8°
2037-08-30 Sun	20	—	unknown	01:20–05:10 (marginal, 3.83 h)	72.5° 06:30	7.52	78%	27.4°
2037-08-31 Mon	26	—	unknown	01:05–05:10 (marginal, 4.08 h)	72.5° 06:25	7.57	69%	16.4°
2037-09-01 Tue	36	—	unknown	00:55–05:10 (marginal, 4.25 h)	72.5° 06:25	7.63	60%	8.7°
2037-09-02 Wed	48	—	unknown	01:50–05:15 (good, 3.42 h)	72.5° 06:20	7.69	50%	13.7°
2037-09-03 Thu	62	—	unknown	01:25–05:15 (good, 3.83 h)	72.5° 06:15	7.74	40%	25.1°
2037-09-04 Fri	80	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:10	7.8	29%	37.8°
2037-09-05 Sat	92	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:05	7.85	20%	51.3°
2037-09-06 Sun	97	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:05	7.91	12%	65.3°
2037-09-07 Mon	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:00	7.96	5%	79.8°
2037-09-08 Tue	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 05:55	8.02	1%	94.7°
2037-09-09 Wed	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:50	8.07	0%	109.7°
2037-09-10 Thu	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.5° 05:50	8.12	2%	124.7°
2037-09-11 Fri	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.5° 05:45	8.18	7%	139.5°
2037-09-12 Sat	100	—	unknown	00:35–05:25 (good, 4.83 h)	72.5° 05:40	8.23	15%	153.8°
2037-09-13 Sun	100	—	unknown	00:30–05:30 (good, 5.0 h)	72.5° 05:35	8.28	24%	166.6°
2037-09-14 Mon	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:30	8.34	34%	170.9°
2037-09-15 Tue	100	—	unknown	00:20–05:30 (good, 5.17 h)	72.5° 05:30	8.39	45%	161.1°
2037-09-16 Wed	100	—	unknown	00:20–05:30 (good, 5.17 h)	72.5° 05:25	8.44	55%	148.9°
2037-09-17 Thu	100	—	unknown	00:20–05:35 (good, 5.25 h)	72.5° 05:20	8.49	65%	136.5°
2037-09-18 Fri	100	—	unknown	00:15–05:35 (good, 5.33 h)	72.5° 05:15	8.55	74%	124.3°
2037-09-19 Sat	100	—	unknown	00:20–05:35 (good, 5.25 h)	72.5° 05:10	8.6	82%	112.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-08-21&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.