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: 01-03 (100), 01-04 (100), 01-05 (100), 01-06 (100), 01-07 (100) — by astronomy; check the weather when the night is within four days.

2028-12-30astronomy score per night — click a bar for that night2029-01-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2029-01-09 Tue	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.5° 20:50	11.34	24%	171.1°
2029-01-10 Wed	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.5° 20:45	11.32	16%	175.1°
2029-01-11 Thu	100	—	unknown	18:55–01:55 (good, 7.0 h)	72.5° 20:45	11.3	8%	161.6°
2029-01-12 Fri	100	—	unknown	18:55–01:50 (good, 6.92 h)	72.5° 20:40	11.28	4%	148.2°
2029-01-13 Sat	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.5° 20:35	11.26	1%	135.0°
2029-01-14 Sun	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.5° 20:30	11.24	0%	122.0°
2029-01-15 Mon	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.5° 20:25	11.22	2%	109.3°
2029-01-16 Tue	100	—	unknown	18:55–01:35 (good, 6.67 h)	72.5° 20:25	11.2	5%	96.8°
2029-01-17 Wed	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.5° 20:20	11.17	10%	84.6°
2029-01-18 Thu	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.15	17%	72.5°
2029-01-19 Fri	99	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.13	24%	60.6°
2029-01-20 Sat	92	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.1	33%	48.8°
2029-01-21 Sun	84	—	unknown	19:05–01:15 (good, 6.17 h)	72.5° 20:05	11.08	42%	37.0°
2029-01-22 Mon	68	—	unknown	19:05–00:45 (good, 5.67 h)	72.5° 20:00	11.05	51%	25.1°
2029-01-23 Tue	54	—	unknown	19:05–01:30 (marginal, 6.42 h)	72.5° 19:55	11.02	61%	13.0°
2029-01-24 Wed	37	—	unknown	19:05–01:20 (marginal, 6.25 h)	72.5° 19:50	10.99	70%	0.8°
2029-01-25 Thu	25	—	unknown	19:05–01:00 (marginal, 5.92 h)	72.5° 19:50	10.96	79%	12.0°
2029-01-26 Fri	18	—	unknown	19:10–00:30 (marginal, 5.33 h)	72.5° 19:45	10.94	87%	25.0°
2029-01-27 Sat	21	—	unknown	19:10–22:55 (marginal, 3.75 h)	72.5° 19:40	10.91	93%	38.5°
2029-01-28 Sun	32	—	unknown	19:10–00:30 (marginal, 5.33 h)	72.5° 19:35	10.88	98%	52.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-12-30&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.