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: 10-23 (100), 10-24 (100), 10-25 (100), 10-26 (100), 10-27 (100) — by astronomy; check the weather when the night is within four days.

2027-10-19astronomy score per night — click a bar for that night2027-11-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-19 Tue	43	—	unknown	21:55–06:10 (marginal, 8.25 h)	72.5° 03:15	9.98	80%	20.3°
2027-10-20 Wed	58	—	unknown	21:40–06:10 (marginal, 8.5 h)	72.5° 03:10	10.02	70%	34.1°
2027-10-21 Thu	85	—	unknown	22:00–05:35 (good, 7.58 h)	72.5° 03:10	10.07	59%	48.0°
2027-10-22 Fri	94	—	unknown	22:00–06:10 (good, 8.17 h)	72.5° 03:05	10.11	48%	62.1°
2027-10-23 Sat	100	—	unknown	21:55–06:15 (good, 8.33 h)	72.5° 03:00	10.15	36%	76.2°
2027-10-24 Sun	100	—	unknown	21:50–06:15 (good, 8.42 h)	72.5° 02:55	10.19	26%	90.5°
2027-10-25 Mon	100	—	unknown	21:45–06:15 (good, 8.5 h)	72.5° 02:55	10.23	16%	104.8°
2027-10-26 Tue	100	—	unknown	21:45–06:15 (good, 8.5 h)	72.5° 02:50	10.27	9%	119.0°
2027-10-27 Wed	100	—	unknown	21:40–06:15 (good, 8.58 h)	72.5° 02:45	10.31	4%	133.2°
2027-10-28 Thu	100	—	unknown	21:35–06:20 (good, 8.75 h)	72.5° 02:40	10.34	1%	147.2°
2027-10-29 Fri	100	—	unknown	21:30–06:20 (good, 8.83 h)	72.5° 02:35	10.38	0%	161.0°
2027-10-30 Sat	100	—	unknown	21:25–05:20 (good, 8.92 h)	72.5° 02:35	10.42	2%	174.5°
2027-10-31 Sun	100	—	unknown	20:25–05:20 (good, 8.92 h)	72.5° 01:30	10.46	6%	172.3°
2027-11-01 Mon	100	—	unknown	20:20–05:20 (good, 9.0 h)	72.5° 01:25	10.49	12%	159.5°
2027-11-02 Tue	100	—	unknown	20:15–05:25 (good, 9.17 h)	72.5° 01:20	10.53	20%	147.0°
2027-11-03 Wed	100	—	unknown	20:15–05:25 (good, 9.17 h)	72.5° 01:15	10.57	28%	134.8°
2027-11-04 Thu	100	—	unknown	20:10–05:25 (good, 9.25 h)	72.5° 01:15	10.6	37%	122.8°
2027-11-05 Fri	100	—	unknown	20:10–05:25 (good, 9.25 h)	72.5° 01:10	10.64	46%	110.9°
2027-11-06 Sat	100	—	unknown	20:10–05:25 (good, 9.25 h)	72.5° 01:05	10.67	56%	99.1°
2027-11-07 Sun	100	—	unknown	20:15–05:30 (good, 9.25 h)	72.5° 01:00	10.7	65%	87.2°
2027-11-08 Mon	100	—	unknown	21:00–05:30 (good, 8.5 h)	72.5° 01:00	10.74	74%	75.2°
2027-11-09 Tue	99	—	unknown	22:40–05:30 (good, 6.83 h)	72.5° 00:55	10.77	82%	63.0°
2027-11-10 Wed	91	—	unknown	02:00–05:30 (good, 3.5 h)	72.5° 00:50	10.8	89%	50.5°
2027-11-11 Thu	82	—	unknown	05:10–05:35 (good, 0.42 h)	72.5° 00:45	10.83	94%	37.8°
2027-11-12 Fri	36	—	unknown	01:20–05:35 (marginal, 4.25 h)	72.5° 00:40	10.86	98%	24.7°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-19&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.