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: 11-23 (70), 11-24 (69), 11-25 (67), 11-26 (65), 11-27 (63) — by astronomy; check the weather when the night is within four days.

2038-11-23astronomy score per night — click a bar for that night2038-12-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-11-23 Tue	70	—	unknown	18:35–21:20 (good, 2.75 h)	71.1° 16:15	11.17	10%	97.4°
2038-11-24 Wed	69	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:10	11.19	4%	86.8°
2038-11-25 Thu	67	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:05	11.21	1%	76.3°
2038-11-26 Fri	65	—	unknown	18:35–21:05 (good, 2.5 h)	71.1° 16:00	11.24	0%	66.2°
2038-11-27 Sat	63	—	unknown	18:35–21:05 (good, 2.5 h)	71.1° 15:55	11.26	3%	57.3°
2038-11-28 Sun	61	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 15:55	11.28	8%	50.4°
2038-11-29 Mon	55	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 15:50	11.3	15%	46.2°
2038-11-30 Tue	47	—	unknown	18:35–20:45 (good, 2.17 h)	71.1° 15:45	11.31	24%	45.3°
2038-12-01 Wed	40	—	unknown	18:35–20:35 (good, 2.0 h)	71.1° 15:40	11.33	34%	47.5°
2038-12-02 Thu	34	—	unknown	18:35–20:25 (good, 1.83 h)	71.1° 15:35	11.35	44%	52.1°
2038-12-03 Fri	29	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:35	11.37	54%	58.3°
2038-12-04 Sat	26	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 15:30	11.38	64%	65.5°
2038-12-05 Sun	24	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 15:25	11.39	72%	73.4°
2038-12-06 Mon	24	—	unknown	18:35–19:15 (good, 0.67 h)	71.1° 15:20	11.41	80%	81.5°
2038-12-07 Tue	24	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 15:20	11.42	87%	89.8°
2038-12-08 Wed	26	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 15:15	11.43	93%	98.1°
2038-12-09 Thu	28	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 15:10	11.44	97%	106.3°
2038-12-10 Fri	30	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 15:05	11.45	99%	114.1°
2038-12-11 Sat	32	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 15:00	11.46	100%	121.3°
2038-12-12 Sun	31	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 15:00	11.47	99%	127.4°
2038-12-13 Mon	32	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:55	11.48	96%	132.0°
2038-12-14 Tue	35	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:50	11.49	90%	134.5°
2038-12-15 Wed	34	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 14:45	11.49	84%	134.3°
2038-12-16 Thu	32	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:40	11.5	75%	131.4°
2038-12-17 Fri	31	—	unknown	18:35–19:45 (good, 1.17 h)	71.1° 14:40	11.5	66%	126.1°
2038-12-18 Sat	30	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 14:35	11.5	55%	118.9°
2038-12-19 Sun	29	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:30	11.51	44%	110.4°
2038-12-20 Mon	27	—	unknown	18:35–19:35 (good, 1.0 h)	71.1° 14:25	11.51	33%	100.9°
2038-12-21 Tue	25	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:25	11.51	23%	90.9°
2038-12-22 Wed	23	—	unknown	18:35–19:25 (good, 0.83 h)	71.1° 14:20	11.51	14%	80.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-11-23&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.