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: 02-08 (5), 02-07 (4), 02-04 (3), 02-05 (3), 02-06 (3) — by astronomy; check the weather when the night is within four days.

2030-01-10astronomy score per night — click a bar for that night2030-02-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-01-10 Thu	0	—	unknown	—	71.1° 13:05	11.32	44%	68.1°
2030-01-11 Fri	0	—	unknown	—	71.1° 13:00	11.3	53%	77.2°
2030-01-12 Sat	0	—	unknown	—	71.1° 12:55	11.29	63%	86.4°
2030-01-13 Sun	0	—	unknown	—	71.1° 12:50	11.27	71%	95.7°
2030-01-14 Mon	0	—	unknown	—	71.1° 12:45	11.25	80%	104.9°
2030-01-15 Tue	0	—	unknown	—	71.1° 12:45	11.22	87%	113.9°
2030-01-16 Wed	0	—	unknown	—	71.1° 12:40	11.2	93%	122.5°
2030-01-17 Thu	0	—	unknown	—	71.1° 12:35	11.18	97%	130.4°
2030-01-18 Fri	0	—	unknown	—	71.1° 12:30	11.16	99%	136.7°
2030-01-19 Sat	0	—	unknown	—	71.1° 12:30	11.13	100%	140.7°
2030-01-20 Sun	0	—	unknown	—	71.1° 12:25	11.11	98%	141.3°
2030-01-21 Mon	0	—	unknown	—	71.1° 12:20	11.08	94%	138.1°
2030-01-22 Tue	0	—	unknown	—	71.1° 12:15	11.05	88%	131.8°
2030-01-23 Wed	0	—	unknown	—	71.1° 12:10	11.03	80%	123.3°
2030-01-24 Thu	0	—	unknown	—	71.1° 12:10	11.0	70%	113.5°
2030-01-25 Fri	0	—	unknown	—	71.1° 12:00	10.97	59%	103.0°
2030-01-26 Sat	0	—	unknown	—	71.1° 12:00	10.94	48%	92.0°
2030-01-27 Sun	0	—	unknown	—	71.1° 11:50	10.91	37%	81.0°
2030-01-28 Mon	1	—	unknown	—	71.1° 11:50	10.88	26%	70.1°
2030-01-29 Tue	1	—	unknown	—	71.1° 11:45	10.85	17%	59.8°
2030-01-30 Wed	1	—	unknown	—	71.1° 11:40	10.82	9%	50.6°
2030-01-31 Thu	1	—	unknown	—	71.1° 11:35	10.79	4%	43.4°
2030-02-01 Fri	1	—	unknown	—	71.1° 11:35	10.76	1%	39.2°
2030-02-02 Sat	1	—	unknown	06:25–06:30 (marginal, 0.08 h)	71.1° 11:30	10.72	0%	38.9°
2030-02-03 Sun	2	—	unknown	05:55–06:00 (marginal, 0.08 h)	71.1° 11:25	10.69	2%	42.3°
2030-02-04 Mon	3	—	unknown	06:20–06:30 (marginal, 0.17 h)	71.1° 11:20	10.65	6%	48.5°
2030-02-05 Tue	3	—	unknown	06:15–06:30 (marginal, 0.25 h)	71.1° 11:15	10.62	12%	56.4°
2030-02-06 Wed	3	—	unknown	06:10–06:25 (marginal, 0.25 h)	71.1° 11:15	10.58	19%	65.1°
2030-02-07 Thu	4	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.55	27%	74.1°
2030-02-08 Fri	5	—	unknown	05:35–05:55 (marginal, 0.33 h)	71.1° 11:05	10.51	36%	83.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-01-10&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.