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), 10-02 (100) — by astronomy; check the weather when the night is within four days.

2042-09-17astronomy score per night — click a bar for that night2042-10-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-09-17 Wed	100	—	unknown	21:05–02:10 (good, 5.08 h)	87.1° 20:10	8.48	11%	82.7°
2042-09-18 Thu	100	—	unknown	21:00–02:10 (good, 5.17 h)	87.1° 20:10	8.54	18%	78.4°
2042-09-19 Fri	100	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.59	25%	74.6°
2042-09-20 Sat	100	—	unknown	21:00–02:00 (good, 5.0 h)	87.1° 20:00	8.64	34%	71.4°
2042-09-21 Sun	99	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.69	44%	68.9°
2042-09-22 Mon	93	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:55	8.74	54%	67.4°
2042-09-23 Tue	85	—	unknown	20:50–01:50 (good, 5.0 h)	87.1° 19:50	8.79	64%	67.0°
2042-09-24 Wed	72	—	unknown	20:50–01:20 (good, 4.5 h)	87.1° 19:45	8.84	74%	67.9°
2042-09-25 Thu	62	—	unknown	20:50–00:40 (good, 3.83 h)	87.1° 19:40	8.89	83%	70.2°
2042-09-26 Fri	59	—	unknown	20:45–23:35 (good, 2.83 h)	87.1° 19:35	8.94	91%	73.7°
2042-09-27 Sat	58	—	unknown	20:45–23:15 (good, 2.5 h)	87.1° 19:35	8.99	96%	78.3°
2042-09-28 Sun	60	—	unknown	20:45–23:20 (good, 2.58 h)	87.1° 19:30	9.04	100%	83.7°
2042-09-29 Mon	66	—	unknown	20:40–23:45 (good, 3.08 h)	87.1° 19:25	9.09	100%	89.6°
2042-09-30 Tue	74	—	unknown	20:40–00:20 (good, 3.67 h)	87.1° 19:20	9.14	97%	95.5°
2042-10-01 Wed	83	—	unknown	20:40–00:50 (good, 4.17 h)	87.1° 19:15	9.19	91%	101.0°
2042-10-02 Thu	100	—	unknown	20:35–00:50 (good, 4.25 h)	87.1° 19:15	9.23	83%	105.8°
2042-10-03 Fri	100	—	unknown	20:35–00:55 (good, 4.33 h)	87.1° 19:10	9.28	73%	109.4°
2042-10-04 Sat	100	—	unknown	20:35–00:55 (good, 4.33 h)	87.1° 19:05	9.33	63%	111.8°
2042-10-05 Sun	100	—	unknown	20:30–00:55 (good, 4.42 h)	87.1° 19:00	9.38	52%	112.9°
2042-10-06 Mon	100	—	unknown	20:30–00:50 (good, 4.33 h)	87.1° 19:00	9.42	41%	112.7°
2042-10-07 Tue	100	—	unknown	20:25–00:55 (good, 4.5 h)	87.1° 18:55	9.47	32%	111.3°
2042-10-08 Wed	100	—	unknown	20:25–00:50 (good, 4.42 h)	87.1° 18:50	9.51	23%	108.9°
2042-10-09 Thu	100	—	unknown	20:25–00:45 (good, 4.33 h)	87.1° 18:45	9.56	15%	105.6°
2042-10-10 Fri	100	—	unknown	20:25–00:40 (good, 4.25 h)	87.1° 18:40	9.61	9%	101.8°
2042-10-11 Sat	100	—	unknown	20:20–00:35 (good, 4.25 h)	87.1° 18:40	9.65	4%	97.5°
2042-10-12 Sun	100	—	unknown	20:20–00:35 (good, 4.25 h)	87.1° 18:35	9.69	1%	93.0°
2042-10-13 Mon	100	—	unknown	20:20–00:30 (good, 4.17 h)	87.1° 18:30	9.74	0%	88.4°
2042-10-14 Tue	100	—	unknown	20:15–00:25 (good, 4.17 h)	87.1° 18:25	9.78	1%	83.8°
2042-10-15 Wed	100	—	unknown	20:15–00:20 (good, 4.08 h)	87.1° 18:20	9.83	3%	79.5°
2042-10-16 Thu	100	—	unknown	20:15–00:20 (good, 4.08 h)	87.1° 18:20	9.87	7%	75.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-09-17&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.