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 HD 189733: 01-01 (5), 01-02 (5), 01-03 (4), 01-04 (4), 01-05 (3) — by astronomy; check the weather when the night is within four days.

2026-01-01astronomy score per night — click a bar for that night2026-01-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-01-01 Thu	5	98	5	18:45–19:10 (marginal, 0.42 h)	71.1° 13:40	11.45	97%	115.8°
2026-01-02 Fri	5	88	4	18:45–19:10 (marginal, 0.42 h)	71.1° 13:35	11.44	100%	124.5°
2026-01-03 Sat	4	0	0	—	71.1° 13:30	11.43	100%	131.1°
2026-01-04 Sun	4	0	0	—	71.1° 13:25	11.42	97%	134.8°
2026-01-05 Mon	3	0	0	—	71.1° 13:25	11.4	92%	134.9°
2026-01-06 Tue	2	0	0	—	71.1° 13:20	11.39	84%	131.9°
2026-01-07 Wed	2	0	0	—	71.1° 13:15	11.37	76%	126.4°
2026-01-08 Thu	1	0	0	—	71.1° 13:10	11.36	67%	119.4°
2026-01-09 Fri	1	84	1	—	71.1° 13:05	11.34	57%	111.7°
2026-01-10 Sat	1	0	0	—	71.1° 13:05	11.32	47%	103.4°
2026-01-11 Sun	1	0	0	—	71.1° 13:00	11.31	38%	95.0°
2026-01-12 Mon	0	64	0	—	71.1° 12:55	11.29	29%	86.6°
2026-01-13 Tue	0	0	0	—	71.1° 12:50	11.27	21%	78.3°
2026-01-14 Wed	0	96	0	—	71.1° 12:45	11.25	14%	70.3°
2026-01-15 Thu	0	97	0	—	71.1° 12:45	11.23	8%	62.6°
2026-01-16 Fri	0	0	0	—	71.1° 12:40	11.2	4%	55.7°
2026-01-17 Sat	0	67	0	—	71.1° 12:35	11.18	1%	50.0°
2026-01-18 Sun	0	0	0	—	71.1° 12:30	11.16	0%	46.1°
2026-01-19 Mon	0	100	0	—	71.1° 12:30	11.13	1%	44.6°
2026-01-20 Tue	0	0	0	—	71.1° 12:25	11.11	5%	46.0°
2026-01-21 Wed	0	0	0	—	71.1° 12:20	11.08	10%	50.0°
2026-01-22 Thu	0	11	0	—	71.1° 12:15	11.06	17%	56.3°
2026-01-23 Fri	0	21	0	—	71.1° 12:10	11.03	26%	64.1°
2026-01-24 Sat	0	0	0	—	71.1° 12:10	11.0	36%	73.0°
2026-01-25 Sun	0	0	0	—	71.1° 12:00	10.97	47%	82.6°
2026-01-26 Mon	0	0	0	—	71.1° 12:00	10.94	58%	92.6°
2026-01-27 Tue	1	62	1	—	71.1° 11:50	10.91	69%	102.7°
2026-01-28 Wed	1	0	0	—	71.1° 11:50	10.88	80%	112.4°
2026-01-29 Thu	1	0	0	—	71.1° 11:45	10.85	88%	121.3°
2026-01-30 Fri	1	0	0	—	71.1° 11:40	10.82	95%	128.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-01-01&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.