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: 11-20 (75), 11-19 (74), 11-21 (74), 11-22 (72), 11-23 (71) — by astronomy; check the weather when the night is within four days.

2043-11-16astronomy score per night — click a bar for that night2043-12-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-11-16 Mon	48	—	unknown	18:40–21:00 (good, 2.33 h)	71.1° 16:40	10.98	100%	98.7°
2043-11-17 Tue	57	—	unknown	18:40–21:25 (good, 2.75 h)	71.1° 16:35	11.01	98%	109.0°
2043-11-18 Wed	64	—	unknown	18:40–21:30 (good, 2.83 h)	71.1° 16:35	11.04	94%	118.4°
2043-11-19 Thu	74	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:30	11.07	87%	126.1°
2043-11-20 Fri	75	—	unknown	18:35–21:25 (good, 2.83 h)	71.1° 16:25	11.09	78%	131.6°
2043-11-21 Sat	74	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:20	11.12	68%	134.0°
2043-11-22 Sun	72	—	unknown	18:35–21:25 (good, 2.83 h)	71.1° 16:20	11.14	57%	133.2°
2043-11-23 Mon	71	—	unknown	18:35–21:20 (good, 2.75 h)	71.1° 16:15	11.16	46%	129.6°
2043-11-24 Tue	70	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:10	11.19	36%	124.1°
2043-11-25 Wed	68	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:05	11.21	27%	117.2°
2043-11-26 Thu	66	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:00	11.23	19%	109.6°
2043-11-27 Fri	64	—	unknown	18:35–21:05 (good, 2.5 h)	71.1° 16:00	11.25	12%	101.5°
2043-11-28 Sat	63	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 15:55	11.27	6%	93.2°
2043-11-29 Sun	61	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 15:50	11.29	3%	84.9°
2043-11-30 Mon	59	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 15:45	11.31	1%	76.8°
2043-12-01 Tue	57	—	unknown	18:35–20:50 (good, 2.25 h)	71.1° 15:40	11.33	0%	69.0°
2043-12-02 Wed	55	—	unknown	18:35–20:45 (good, 2.17 h)	71.1° 15:40	11.35	2%	61.7°
2043-12-03 Thu	54	—	unknown	18:35–20:40 (good, 2.08 h)	71.1° 15:35	11.36	5%	55.3°
2043-12-04 Fri	51	—	unknown	18:35–20:35 (good, 2.0 h)	71.1° 15:30	11.38	10%	50.2°
2043-12-05 Sat	45	—	unknown	18:35–20:35 (good, 2.0 h)	71.1° 15:25	11.39	16%	46.8°
2043-12-06 Sun	39	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 15:25	11.41	24%	45.7°
2043-12-07 Mon	33	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:20	11.42	33%	47.2°
2043-12-08 Tue	28	—	unknown	18:35–20:00 (good, 1.42 h)	71.1° 15:15	11.43	42%	51.1°
2043-12-09 Wed	23	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 15:10	11.44	53%	57.1°
2043-12-10 Thu	20	—	unknown	18:35–18:55 (good, 0.33 h)	71.1° 15:05	11.45	64%	64.8°
2043-12-11 Fri	18	—	unknown	18:00–20:30 (marginal, 2.5 h)	71.1° 15:05	11.46	74%	73.7°
2043-12-12 Sat	18	—	unknown	18:35–18:40 (good, 0.08 h)	71.1° 15:00	11.47	83%	83.5°
2043-12-13 Sun	20	—	unknown	18:35–19:05 (good, 0.5 h)	71.1° 14:55	11.48	91%	93.8°
2043-12-14 Mon	22	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:50	11.49	97%	104.2°
2043-12-15 Tue	25	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 14:45	11.49	100%	114.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-11-16&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.