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: 10-23 (100), 10-24 (100), 10-25 (100), 10-26 (100), 10-27 (100) — by astronomy; check the weather when the night is within four days.

2030-10-23astronomy score per night — click a bar for that night2030-11-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-10-23 Wed	100	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:15	10.16	11%	126.9°
2030-10-24 Thu	100	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:10	10.2	5%	117.3°
2030-10-25 Fri	100	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:05	10.24	1%	106.5°
2030-10-26 Sat	100	—	unknown	20:00–00:10 (good, 4.17 h)	71.1° 19:05	10.28	0%	95.0°
2030-10-27 Sun	100	—	unknown	19:00–23:05 (good, 4.08 h)	71.1° 18:00	10.32	2%	83.3°
2030-10-28 Mon	100	—	unknown	18:55–23:00 (good, 4.08 h)	71.1° 17:55	10.35	6%	71.6°
2030-10-29 Tue	100	—	unknown	18:55–22:55 (good, 4.0 h)	71.1° 17:50	10.39	13%	60.6°
2030-10-30 Wed	95	—	unknown	18:55–22:55 (good, 4.0 h)	71.1° 17:45	10.43	22%	50.7°
2030-10-31 Thu	79	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:45	10.47	32%	42.9°
2030-11-01 Fri	63	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:40	10.5	44%	38.4°
2030-11-02 Sat	49	—	unknown	18:50–22:00 (good, 3.17 h)	71.1° 17:35	10.54	55%	37.8°
2030-11-03 Sun	39	—	unknown	18:50–19:50 (good, 1.0 h)	71.1° 17:30	10.57	65%	41.3°
2030-11-04 Mon	33	—	unknown	18:50–22:50 (marginal, 4.0 h)	71.1° 17:25	10.61	75%	47.6°
2030-11-05 Tue	31	—	unknown	18:50–22:40 (marginal, 3.83 h)	71.1° 17:25	10.64	83%	55.6°
2030-11-06 Wed	32	—	unknown	18:45–22:35 (marginal, 3.83 h)	71.1° 17:20	10.68	90%	64.6°
2030-11-07 Thu	36	—	unknown	18:45–19:30 (good, 0.75 h)	71.1° 17:15	10.71	95%	74.0°
2030-11-08 Fri	42	—	unknown	18:45–20:15 (good, 1.5 h)	71.1° 17:10	10.74	98%	83.7°
2030-11-09 Sat	50	—	unknown	18:45–21:00 (good, 2.25 h)	71.1° 17:10	10.78	100%	93.3°
2030-11-10 Sun	58	—	unknown	18:45–21:45 (good, 3.0 h)	71.1° 17:05	10.81	99%	102.8°
2030-11-11 Mon	67	—	unknown	18:45–21:50 (good, 3.08 h)	71.1° 17:00	10.84	97%	112.0°
2030-11-12 Tue	81	—	unknown	18:40–21:50 (good, 3.17 h)	71.1° 16:55	10.87	93%	120.7°
2030-11-13 Wed	82	—	unknown	18:40–21:50 (good, 3.17 h)	71.1° 16:50	10.9	88%	128.6°
2030-11-14 Thu	82	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:50	10.93	81%	135.3°
2030-11-15 Fri	83	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:45	10.96	73%	140.2°
2030-11-16 Sat	82	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:40	10.99	64%	142.4°
2030-11-17 Sun	80	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:35	11.02	54%	141.4°
2030-11-18 Mon	78	—	unknown	18:40–21:40 (good, 3.0 h)	71.1° 16:30	11.04	44%	137.2°
2030-11-19 Tue	77	—	unknown	18:35–21:35 (good, 3.0 h)	71.1° 16:30	11.07	34%	130.3°
2030-11-20 Wed	76	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:25	11.1	24%	121.6°
2030-11-21 Thu	74	—	unknown	18:35–21:25 (good, 2.83 h)	71.1° 16:20	11.12	16%	111.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-10-23&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.