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: 12-23 (12), 12-24 (10), 12-25 (9), 12-26 (9), 12-27 (9) — by astronomy; check the weather when the night is within four days.

2047-12-23astronomy score per night — click a bar for that night2048-01-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-12-23 Mon	12	—	unknown	18:40–18:50 (good, 0.17 h)	71.2° 14:15	11.51	48%	58.7°
2047-12-24 Tue	10	—	unknown	18:40–19:45 (marginal, 1.08 h)	71.1° 14:10	11.5	58%	67.2°
2047-12-25 Wed	9	—	unknown	18:40–19:40 (marginal, 1.0 h)	71.1° 14:10	11.5	68%	76.2°
2047-12-26 Thu	9	—	unknown	18:40–19:35 (marginal, 0.92 h)	71.2° 14:05	11.5	76%	85.3°
2047-12-27 Fri	9	—	unknown	18:40–19:30 (marginal, 0.83 h)	71.2° 14:00	11.49	84%	94.4°
2047-12-28 Sat	9	—	unknown	18:05–19:30 (marginal, 1.42 h)	71.2° 13:55	11.49	90%	103.5°
2047-12-29 Sun	9	—	unknown	18:05–19:25 (marginal, 1.33 h)	71.1° 13:50	11.48	95%	112.4°
2047-12-30 Mon	9	—	unknown	18:40–18:45 (good, 0.08 h)	71.2° 13:50	11.47	98%	120.9°
2047-12-31 Tue	7	—	unknown	18:45–19:20 (marginal, 0.58 h)	71.2° 13:45	11.46	100%	128.6°
2048-01-01 Wed	7	—	unknown	18:45–19:15 (marginal, 0.5 h)	71.2° 13:40	11.45	100%	135.0°
2048-01-02 Thu	6	—	unknown	18:45–19:10 (marginal, 0.42 h)	71.2° 13:35	11.44	97%	139.4°
2048-01-03 Fri	6	—	unknown	18:10–18:40 (marginal, 0.5 h)	71.1° 13:35	11.43	93%	140.8°
2048-01-04 Sat	5	—	unknown	18:10–18:35 (marginal, 0.42 h)	71.2° 13:30	11.42	87%	138.7°
2048-01-05 Sun	4	—	unknown	18:45–19:00 (marginal, 0.25 h)	71.2° 13:25	11.41	79%	133.6°
2048-01-06 Mon	3	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.2° 13:20	11.39	70%	126.2°
2048-01-07 Tue	2	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.1° 13:15	11.38	59%	117.2°
2048-01-08 Wed	2	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:15	11.36	48%	107.1°
2048-01-09 Thu	1	—	unknown	—	71.2° 13:10	11.35	37%	96.4°
2048-01-10 Fri	1	—	unknown	—	71.2° 13:05	11.33	26%	85.3°
2048-01-11 Sat	1	—	unknown	—	71.2° 13:00	11.31	17%	74.2°
2048-01-12 Sun	1	—	unknown	—	71.1° 12:55	11.29	9%	63.4°
2048-01-13 Mon	0	—	unknown	—	71.2° 12:55	11.27	3%	53.6°
2048-01-14 Tue	0	—	unknown	—	71.2° 12:50	11.25	0%	45.6°
2048-01-15 Wed	0	—	unknown	—	71.2° 12:45	11.23	0%	40.5°
2048-01-16 Thu	0	—	unknown	—	71.2° 12:40	11.21	3%	39.3°
2048-01-17 Fri	0	—	unknown	—	71.1° 12:40	11.19	8%	42.2°
2048-01-18 Sat	0	—	unknown	—	71.2° 12:35	11.16	14%	48.1°
2048-01-19 Sun	0	—	unknown	—	71.2° 12:30	11.14	22%	55.7°
2048-01-20 Mon	0	—	unknown	—	71.2° 12:25	11.12	31%	64.3°
2048-01-21 Tue	0	—	unknown	—	71.1° 12:20	11.09	41%	73.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-12-23&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.