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: 11-19 (100), 11-20 (100), 11-21 (100), 11-22 (100), 11-23 (100) — by astronomy; check the weather when the night is within four days.

2027-11-13astronomy score per night — click a bar for that night2027-12-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-11-13 Sat	26	—	unknown	02:55–05:35 (marginal, 2.67 h)	72.5° 00:40	10.89	100%	11.3°
2027-11-14 Sun	23	—	unknown	19:45–21:00 (marginal, 1.25 h)	72.5° 00:35	10.92	99%	2.5°
2027-11-15 Mon	31	—	unknown	19:20–23:10 (marginal, 3.83 h)	72.5° 00:30	10.95	96%	16.4°
2027-11-16 Tue	44	—	unknown	19:05–01:55 (marginal, 6.83 h)	72.5° 00:25	10.98	90%	30.5°
2027-11-17 Wed	82	—	unknown	19:15–20:00 (good, 0.75 h)	72.5° 00:20	11.01	83%	44.7°
2027-11-18 Thu	92	—	unknown	19:10–02:25 (good, 7.25 h)	72.5° 00:20	11.04	73%	58.9°
2027-11-19 Fri	100	—	unknown	19:10–04:25 (good, 9.25 h)	72.5° 00:15	11.06	63%	73.1°
2027-11-20 Sat	100	—	unknown	19:05–05:05 (good, 10.0 h)	72.5° 00:10	11.09	51%	87.3°
2027-11-21 Sun	100	—	unknown	19:00–05:10 (good, 10.17 h)	72.5° 00:05	11.11	40%	101.4°
2027-11-22 Mon	100	—	unknown	18:55–05:10 (good, 10.25 h)	72.5° 00:00	11.14	29%	115.3°
2027-11-23 Tue	100	—	unknown	18:55–05:10 (good, 10.25 h)	72.5° 00:00	11.16	20%	129.2°
2027-11-24 Wed	100	—	unknown	18:50–05:05 (good, 10.25 h)	72.5° 23:55	11.19	12%	142.9°
2027-11-25 Thu	100	—	unknown	18:45–05:00 (good, 10.25 h)	72.5° 23:50	11.21	6%	156.5°
2027-11-26 Fri	100	—	unknown	18:40–05:00 (good, 10.33 h)	72.5° 23:45	11.23	2%	169.8°
2027-11-27 Sat	100	—	unknown	18:35–04:55 (good, 10.33 h)	72.5° 23:45	11.25	0%	177.0°
2027-11-28 Sun	100	—	unknown	18:35–04:50 (good, 10.25 h)	72.5° 23:40	11.27	1%	164.1°
2027-11-29 Mon	100	—	unknown	18:35–04:45 (good, 10.17 h)	72.5° 23:35	11.29	3%	151.4°
2027-11-30 Tue	100	—	unknown	18:35–04:40 (good, 10.08 h)	72.5° 23:30	11.31	8%	139.0°
2027-12-01 Wed	100	—	unknown	18:35–04:40 (good, 10.08 h)	72.5° 23:25	11.33	14%	126.9°
2027-12-02 Thu	100	—	unknown	18:35–04:35 (good, 10.0 h)	72.5° 23:25	11.34	21%	114.9°
2027-12-03 Fri	100	—	unknown	18:35–04:30 (good, 9.92 h)	72.5° 23:20	11.36	29%	103.0°
2027-12-04 Sat	100	—	unknown	18:35–04:25 (good, 9.83 h)	72.5° 23:15	11.38	38%	91.2°
2027-12-05 Sun	100	—	unknown	18:35–04:20 (good, 9.75 h)	72.5° 23:10	11.39	47%	79.3°
2027-12-06 Mon	100	—	unknown	18:40–04:20 (good, 9.67 h)	72.5° 23:05	11.4	57%	67.3°
2027-12-07 Tue	95	—	unknown	20:20–04:15 (good, 7.92 h)	72.5° 23:05	11.42	66%	55.2°
2027-12-08 Wed	86	—	unknown	00:00–04:10 (good, 4.17 h)	72.5° 23:00	11.43	75%	42.7°
2027-12-09 Thu	63	—	unknown	04:00–04:05 (good, 0.08 h)	72.5° 22:55	11.44	83%	29.9°
2027-12-10 Fri	38	—	unknown	18:35–04:15 (marginal, 9.67 h)	72.5° 22:50	11.45	90%	16.7°
2027-12-11 Sat	26	—	unknown	01:05–03:50 (marginal, 2.75 h)	72.5° 22:50	11.46	96%	3.1°
2027-12-12 Sun	22	—	unknown	18:35–20:10 (marginal, 1.58 h)	72.5° 22:45	11.47	99%	10.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-11-13&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.