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: 10-04 (100), 10-05 (100), 10-06 (100), 10-07 (100), 10-08 (100) — by astronomy; check the weather when the night is within four days.

2037-09-22astronomy score per night — click a bar for that night2037-10-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-09-22 Tue	76	—	unknown	02:00–05:40 (good, 3.67 h)	72.5° 05:00	8.75	98%	76.8°
2037-09-23 Wed	59	—	unknown	04:00–05:40 (good, 1.67 h)	72.5° 04:55	8.8	100%	65.1°
2037-09-24 Thu	42	—	unknown	23:50–05:40 (marginal, 5.83 h)	72.5° 04:55	8.85	100%	53.4°
2037-09-25 Fri	29	—	unknown	23:55–05:40 (marginal, 5.75 h)	72.5° 04:50	8.9	98%	41.8°
2037-09-26 Sat	20	—	unknown	00:00–05:45 (marginal, 5.75 h)	72.5° 04:45	8.95	94%	30.2°
2037-09-27 Sun	21	—	unknown	23:40–05:45 (marginal, 6.08 h)	72.5° 04:40	9.0	89%	19.0°
2037-09-28 Mon	28	—	unknown	23:25–05:45 (marginal, 6.33 h)	72.5° 04:35	9.05	83%	9.7°
2037-09-29 Tue	39	—	unknown	23:10–05:45 (marginal, 6.58 h)	72.5° 04:35	9.1	75%	11.0°
2037-09-30 Wed	54	—	unknown	22:55–05:50 (marginal, 6.92 h)	72.5° 04:30	9.15	66%	21.5°
2037-10-01 Thu	67	—	unknown	23:40–05:15 (good, 5.58 h)	72.5° 04:25	9.2	55%	33.6°
2037-10-02 Fri	85	—	unknown	23:15–05:50 (good, 6.58 h)	72.5° 04:20	9.24	45%	46.5°
2037-10-03 Sat	93	—	unknown	23:10–05:50 (good, 6.67 h)	72.5° 04:15	9.29	34%	59.9°
2037-10-04 Sun	100	—	unknown	23:10–05:50 (good, 6.67 h)	72.5° 04:15	9.34	24%	73.8°
2037-10-05 Mon	100	—	unknown	23:05–05:55 (good, 6.83 h)	72.5° 04:10	9.38	15%	88.1°
2037-10-06 Tue	100	—	unknown	23:00–05:55 (good, 6.92 h)	72.5° 04:05	9.43	7%	102.8°
2037-10-07 Wed	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 04:00	9.48	2%	117.7°
2037-10-08 Thu	100	—	unknown	22:50–05:55 (good, 7.08 h)	72.5° 04:00	9.52	0%	132.7°
2037-10-09 Fri	100	—	unknown	22:50–06:00 (good, 7.17 h)	72.5° 03:55	9.57	1%	147.5°
2037-10-10 Sat	100	—	unknown	22:45–06:00 (good, 7.25 h)	72.5° 03:50	9.61	5%	161.5°
2037-10-11 Sun	100	—	unknown	22:40–06:00 (good, 7.33 h)	72.5° 03:45	9.66	11%	171.5°
2037-10-12 Mon	100	—	unknown	22:35–06:00 (good, 7.42 h)	72.5° 03:40	9.7	20%	165.4°
2037-10-13 Tue	100	—	unknown	22:30–06:00 (good, 7.5 h)	72.5° 03:40	9.75	29%	153.0°
2037-10-14 Wed	100	—	unknown	22:30–06:05 (good, 7.58 h)	72.5° 03:35	9.79	39%	140.3°
2037-10-15 Thu	100	—	unknown	22:30–06:05 (good, 7.58 h)	72.5° 03:30	9.84	49%	127.8°
2037-10-16 Fri	100	—	unknown	22:25–06:05 (good, 7.67 h)	72.5° 03:25	9.88	59%	115.5°
2037-10-17 Sat	100	—	unknown	22:30–06:05 (good, 7.58 h)	72.5° 03:20	9.92	68%	103.5°
2037-10-18 Sun	100	—	unknown	22:35–06:10 (good, 7.58 h)	72.5° 03:20	9.96	77%	91.6°
2037-10-19 Mon	100	—	unknown	23:15–06:10 (good, 6.92 h)	72.5° 03:15	10.01	84%	79.9°
2037-10-20 Tue	100	—	unknown	00:45–06:10 (good, 5.42 h)	72.5° 03:10	10.05	90%	68.2°
2037-10-21 Wed	96	—	unknown	03:30–06:10 (good, 2.67 h)	72.5° 03:05	10.09	95%	56.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-09-22&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.