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: 10-30 (100), 10-31 (100), 11-01 (100), 11-02 (96), 11-03 (84) — by astronomy; check the weather when the night is within four days.

2027-10-30astronomy score per night — click a bar for that night2027-11-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-30 Sat	100	—	unknown	19:55–23:55 (good, 4.0 h)	71.1° 18:50	10.42	2%	81.9°
2027-10-31 Sun	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:45	10.46	6%	72.3°
2027-11-01 Mon	100	—	unknown	18:55–22:45 (good, 3.83 h)	71.1° 17:40	10.49	12%	63.4°
2027-11-02 Tue	96	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:35	10.53	20%	55.5°
2027-11-03 Wed	84	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:30	10.57	28%	49.0°
2027-11-04 Thu	71	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:30	10.6	37%	44.3°
2027-11-05 Fri	58	—	unknown	18:50–22:15 (good, 3.42 h)	71.1° 17:25	10.64	46%	41.9°
2027-11-06 Sat	48	—	unknown	18:45–21:50 (good, 3.08 h)	71.1° 17:20	10.67	56%	42.3°
2027-11-07 Sun	40	—	unknown	18:45–20:05 (good, 1.33 h)	71.1° 17:15	10.7	65%	45.2°
2027-11-08 Mon	34	—	unknown	18:45–19:05 (good, 0.33 h)	71.1° 17:15	10.74	74%	50.4°
2027-11-09 Tue	31	—	unknown	18:45–22:25 (marginal, 3.67 h)	71.1° 17:10	10.77	82%	57.2°
2027-11-10 Wed	31	—	unknown	18:10–22:20 (marginal, 4.17 h)	71.1° 17:05	10.8	89%	65.3°
2027-11-11 Thu	34	—	unknown	18:45–19:20 (good, 0.58 h)	71.1° 17:00	10.83	94%	74.3°
2027-11-12 Fri	40	—	unknown	18:40–20:00 (good, 1.33 h)	71.1° 16:55	10.86	98%	83.9°
2027-11-13 Sat	47	—	unknown	18:40–20:45 (good, 2.08 h)	71.1° 16:55	10.89	100%	93.9°
2027-11-14 Sun	56	—	unknown	18:40–21:30 (good, 2.83 h)	71.1° 16:50	10.92	99%	104.0°
2027-11-15 Mon	65	—	unknown	18:40–21:35 (good, 2.92 h)	71.1° 16:45	10.95	96%	113.9°
2027-11-16 Tue	76	—	unknown	18:40–21:40 (good, 3.0 h)	71.1° 16:40	10.98	90%	123.1°
2027-11-17 Wed	77	—	unknown	18:40–21:35 (good, 2.92 h)	71.1° 16:35	11.01	83%	130.9°
2027-11-18 Thu	77	—	unknown	18:40–21:35 (good, 2.92 h)	71.1° 16:35	11.04	73%	136.3°
2027-11-19 Fri	78	—	unknown	18:35–21:35 (good, 3.0 h)	71.1° 16:30	11.06	63%	138.4°
2027-11-20 Sat	76	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:25	11.09	51%	136.6°
2027-11-21 Sun	74	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:20	11.11	40%	131.4°
2027-11-22 Mon	72	—	unknown	18:35–21:25 (good, 2.83 h)	71.1° 16:20	11.14	29%	123.9°
2027-11-23 Tue	71	—	unknown	18:35–21:20 (good, 2.75 h)	71.1° 16:15	11.16	20%	115.0°
2027-11-24 Wed	69	—	unknown	18:35–21:15 (good, 2.67 h)	71.1° 16:10	11.19	12%	105.3°
2027-11-25 Thu	68	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:05	11.21	6%	95.3°
2027-11-26 Fri	66	—	unknown	18:35–21:10 (good, 2.58 h)	71.1° 16:00	11.23	2%	85.3°
2027-11-27 Sat	64	—	unknown	18:35–21:05 (good, 2.5 h)	71.1° 16:00	11.25	0%	75.6°
2027-11-28 Sun	62	—	unknown	18:35–21:00 (good, 2.42 h)	71.1° 15:55	11.27	1%	66.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-30&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.