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 Vega: 10-21 (100), 10-22 (100), 10-23 (99), 10-24 (99), 10-25 (97) — by astronomy; check the weather when the night is within four days.

2027-10-21astronomy score per night — click a bar for that night2027-11-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-21 Thu	100	—	unknown	20:05–23:55 (good, 3.83 h)	87.1° 18:00	10.07	59%	116.5°
2027-10-22 Fri	100	—	unknown	20:05–23:55 (good, 3.83 h)	87.1° 17:55	10.11	48%	116.5°
2027-10-23 Sat	99	—	unknown	20:05–23:50 (good, 3.75 h)	87.1° 17:50	10.15	36%	114.8°
2027-10-24 Sun	99	—	unknown	20:00–23:45 (good, 3.75 h)	87.1° 17:50	10.19	26%	111.4°
2027-10-25 Mon	97	—	unknown	20:00–23:45 (good, 3.75 h)	87.1° 17:45	10.23	16%	106.8°
2027-10-26 Tue	95	—	unknown	20:00–23:40 (good, 3.67 h)	87.1° 17:40	10.27	9%	101.3°
2027-10-27 Wed	94	—	unknown	20:00–23:35 (good, 3.58 h)	87.1° 17:35	10.31	4%	95.2°
2027-10-28 Thu	95	—	unknown	19:55–23:30 (good, 3.58 h)	87.1° 17:30	10.34	1%	88.9°
2027-10-29 Fri	93	—	unknown	19:55–23:25 (good, 3.5 h)	87.1° 17:30	10.38	0%	82.8°
2027-10-30 Sat	91	—	unknown	19:55–23:25 (good, 3.5 h)	87.1° 17:25	10.42	2%	77.1°
2027-10-31 Sun	90	—	unknown	18:55–22:20 (good, 3.42 h)	87.1° 16:20	10.46	6%	72.1°
2027-11-01 Mon	88	—	unknown	18:55–22:15 (good, 3.33 h)	87.1° 16:15	10.49	12%	68.1°
2027-11-02 Tue	81	—	unknown	18:50–22:10 (good, 3.33 h)	87.1° 16:10	10.53	20%	65.2°
2027-11-03 Wed	73	—	unknown	18:50–22:10 (good, 3.33 h)	87.1° 16:10	10.57	28%	63.6°
2027-11-04 Thu	64	—	unknown	18:50–22:05 (good, 3.25 h)	87.1° 16:05	10.6	37%	63.2°
2027-11-05 Fri	55	—	unknown	18:50–21:45 (good, 2.92 h)	87.1° 16:00	10.64	46%	64.0°
2027-11-06 Sat	50	—	unknown	18:45–21:30 (good, 2.75 h)	87.1° 15:55	10.67	56%	66.0°
2027-11-07 Sun	43	—	unknown	18:45–21:10 (good, 2.42 h)	87.1° 15:55	10.7	65%	69.1°
2027-11-08 Mon	39	—	unknown	18:45–20:20 (good, 1.58 h)	87.1° 15:50	10.74	74%	73.1°
2027-11-09 Tue	36	—	unknown	18:45–19:55 (good, 1.17 h)	87.1° 15:45	10.77	82%	77.8°
2027-11-10 Wed	35	—	unknown	18:45–19:50 (good, 1.08 h)	87.1° 15:40	10.8	89%	83.1°
2027-11-11 Thu	36	—	unknown	18:45–20:00 (good, 1.25 h)	87.1° 15:35	10.83	94%	88.8°
2027-11-12 Fri	39	—	unknown	18:40–20:20 (good, 1.67 h)	87.1° 15:35	10.86	98%	94.7°
2027-11-13 Sat	43	—	unknown	18:40–20:50 (good, 2.17 h)	87.1° 15:30	10.89	100%	100.5°
2027-11-14 Sun	47	—	unknown	18:40–21:00 (good, 2.33 h)	87.1° 15:25	10.92	99%	106.0°
2027-11-15 Mon	51	—	unknown	18:40–21:00 (good, 2.33 h)	87.1° 15:20	10.95	96%	110.7°
2027-11-16 Tue	61	—	unknown	18:40–21:05 (good, 2.42 h)	87.1° 15:15	10.98	90%	114.4°
2027-11-17 Wed	63	—	unknown	18:40–21:05 (good, 2.42 h)	87.1° 15:15	11.01	83%	116.5°
2027-11-18 Thu	63	—	unknown	18:40–21:10 (good, 2.5 h)	87.1° 15:10	11.04	73%	116.9°
2027-11-19 Fri	62	—	unknown	18:35–21:05 (good, 2.5 h)	87.1° 15:05	11.06	63%	115.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-21&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.