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: 12-10 (100), 12-11 (100), 12-12 (100), 12-13 (100), 12-14 (100) — by astronomy; check the weather when the night is within four days.

2028-12-10astronomy score per night — click a bar for that night2029-01-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-12-10 Sun	100	—	unknown	18:35–03:55 (good, 9.33 h)	72.5° 22:50	11.46	31%	132.1°
2028-12-11 Mon	100	—	unknown	18:35–03:55 (good, 9.33 h)	72.5° 22:45	11.47	21%	146.4°
2028-12-12 Tue	100	—	unknown	18:35–03:50 (good, 9.25 h)	72.5° 22:40	11.48	12%	160.6°
2028-12-13 Wed	100	—	unknown	18:35–03:50 (good, 9.25 h)	72.5° 22:35	11.48	6%	174.8°
2028-12-14 Thu	100	—	unknown	18:35–03:45 (good, 9.17 h)	72.5° 22:35	11.49	2%	171.1°
2028-12-15 Fri	100	—	unknown	18:35–03:40 (good, 9.08 h)	72.5° 22:30	11.49	0%	157.2°
2028-12-16 Sat	100	—	unknown	18:35–03:35 (good, 9.0 h)	72.5° 22:25	11.5	1%	143.7°
2028-12-17 Sun	100	—	unknown	18:35–03:30 (good, 8.92 h)	72.5° 22:20	11.5	4%	130.4°
2028-12-18 Mon	100	—	unknown	18:35–03:30 (good, 8.92 h)	72.5° 22:15	11.51	9%	117.5°
2028-12-19 Tue	100	—	unknown	18:35–03:25 (good, 8.83 h)	72.5° 22:15	11.51	15%	104.8°
2028-12-20 Wed	100	—	unknown	18:35–03:20 (good, 8.75 h)	72.5° 22:10	11.51	23%	92.5°
2028-12-21 Thu	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.5° 22:05	11.51	32%	80.4°
2028-12-22 Fri	100	—	unknown	18:35–03:10 (good, 8.58 h)	72.5° 22:00	11.51	41%	68.5°
2028-12-23 Sat	96	—	unknown	18:40–03:10 (good, 8.5 h)	72.5° 22:00	11.5	50%	56.7°
2028-12-24 Sun	88	—	unknown	19:30–03:05 (good, 7.58 h)	72.5° 21:55	11.5	60%	44.8°
2028-12-25 Mon	80	—	unknown	23:45–01:35 (good, 1.83 h)	72.5° 21:50	11.5	69%	32.9°
2028-12-26 Tue	51	—	unknown	18:40–03:20 (marginal, 8.67 h)	72.5° 21:45	11.49	77%	20.8°
2028-12-27 Wed	36	—	unknown	18:40–03:05 (marginal, 8.42 h)	72.5° 21:40	11.49	85%	8.5°
2028-12-28 Thu	24	—	unknown	23:10–02:40 (marginal, 3.5 h)	72.5° 21:40	11.48	92%	4.2°
2028-12-29 Fri	21	—	unknown	18:40–20:10 (marginal, 1.5 h)	72.5° 21:35	11.47	96%	17.2°
2028-12-30 Sat	23	—	unknown	18:40–20:45 (marginal, 2.08 h)	72.5° 21:30	11.47	99%	30.5°
2028-12-31 Sun	41	—	unknown	18:45–00:20 (marginal, 5.58 h)	72.5° 21:25	11.46	100%	44.1°
2029-01-01 Mon	64	—	unknown	18:45–20:10 (good, 1.42 h)	72.5° 21:20	11.45	98%	58.0°
2029-01-02 Tue	99	—	unknown	18:45–23:25 (good, 4.67 h)	72.5° 21:20	11.44	94%	72.1°
2029-01-03 Wed	100	—	unknown	18:45–01:10 (good, 6.42 h)	72.5° 21:15	11.42	87%	86.3°
2029-01-04 Thu	100	—	unknown	18:45–02:00 (good, 7.25 h)	72.5° 21:10	11.41	78%	100.6°
2029-01-05 Fri	100	—	unknown	18:45–02:10 (good, 7.42 h)	72.5° 21:05	11.4	68%	114.9°
2029-01-06 Sat	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.5° 21:05	11.38	57%	129.1°
2029-01-07 Sun	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 21:00	11.37	46%	143.2°
2029-01-08 Mon	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:55	11.35	35%	157.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-12-10&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.