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: 09-17 (100), 09-18 (100), 09-19 (100), 09-20 (100), 09-21 (100) — by astronomy; check the weather when the night is within four days.

2044-09-17astronomy score per night — click a bar for that night2044-10-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-09-17 Sat	100	—	unknown	21:05–02:10 (good, 5.08 h)	87.1° 20:10	8.51	16%	112.9°
2044-09-18 Sun	100	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.56	8%	110.3°
2044-09-19 Mon	100	—	unknown	21:00–02:00 (good, 5.0 h)	87.1° 20:05	8.61	3%	106.5°
2044-09-20 Tue	100	—	unknown	20:55–02:00 (good, 5.08 h)	87.1° 20:00	8.67	0%	101.8°
2044-09-21 Wed	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.72	0%	96.5°
2044-09-22 Thu	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:50	8.77	3%	91.1°
2044-09-23 Fri	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.82	7%	85.7°
2044-09-24 Sat	100	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:45	8.87	13%	80.7°
2044-09-25 Sun	100	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.92	21%	76.1°
2044-09-26 Mon	100	—	unknown	20:45–01:35 (good, 4.83 h)	87.1° 19:35	8.97	29%	72.3°
2044-09-27 Tue	100	—	unknown	20:45–01:30 (good, 4.75 h)	87.1° 19:30	9.02	38%	69.2°
2044-09-28 Wed	93	—	unknown	20:40–01:25 (good, 4.75 h)	87.1° 19:25	9.07	48%	67.1°
2044-09-29 Thu	86	—	unknown	20:40–01:20 (good, 4.67 h)	87.1° 19:25	9.11	57%	66.0°
2044-09-30 Fri	72	—	unknown	20:40–01:00 (good, 4.33 h)	87.1° 19:20	9.16	66%	66.0°
2044-10-01 Sat	62	—	unknown	20:35–00:45 (good, 4.17 h)	87.1° 19:15	9.21	75%	67.1°
2044-10-02 Sun	56	—	unknown	20:35–23:30 (good, 2.92 h)	87.1° 19:10	9.26	83%	69.3°
2044-10-03 Mon	52	—	unknown	20:35–22:45 (good, 2.17 h)	87.1° 19:05	9.31	90%	72.4°
2044-10-04 Tue	51	—	unknown	20:30–22:25 (good, 1.92 h)	87.1° 19:05	9.35	95%	76.5°
2044-10-05 Wed	52	—	unknown	20:30–22:30 (good, 2.0 h)	87.1° 19:00	9.4	99%	81.2°
2044-10-06 Thu	57	—	unknown	20:30–22:50 (good, 2.33 h)	87.1° 18:55	9.45	100%	86.5°
2044-10-07 Fri	64	—	unknown	20:25–23:20 (good, 2.92 h)	87.1° 18:50	9.49	99%	92.1°
2044-10-08 Sat	71	—	unknown	20:25–00:00 (good, 3.58 h)	87.1° 18:50	9.54	96%	97.6°
2044-10-09 Sun	80	—	unknown	20:25–00:20 (good, 3.92 h)	87.1° 18:45	9.58	90%	102.8°
2044-10-10 Mon	99	—	unknown	20:20–00:20 (good, 4.0 h)	87.1° 18:40	9.63	82%	107.4°
2044-10-11 Tue	100	—	unknown	20:20–00:25 (good, 4.08 h)	87.1° 18:35	9.67	72%	111.0°
2044-10-12 Wed	100	—	unknown	20:20–00:25 (good, 4.08 h)	87.1° 18:30	9.72	61%	113.4°
2044-10-13 Thu	100	—	unknown	20:15–00:20 (good, 4.08 h)	87.1° 18:30	9.76	50%	114.2°
2044-10-14 Fri	100	—	unknown	20:15–00:25 (good, 4.17 h)	87.1° 18:25	9.81	39%	113.5°
2044-10-15 Sat	100	—	unknown	20:15–00:20 (good, 4.08 h)	87.1° 18:20	9.85	28%	111.3°
2044-10-16 Sun	100	—	unknown	20:10–00:15 (good, 4.08 h)	87.1° 18:15	9.89	18%	107.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-09-17&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.